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Main
Date: 23 Aug 2007 13:30:30
From: Laurence Darby
Subject: shimano rear deralieur compatibilty question
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Hi,
On sheldonbrown.com/harris/derailers-rear.html it says "9 speed"
deraillieurs should work with 7/8/9 speed drivetrains. I asked an
online shop (not them) if the IG70 Chain and HG50 7 Speed Freewheel are
compatible with the XT M760 SGS rear deraillieur and they said it's
not. Can anyone shed any light on this?
Thanks,
Laurence
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Date: 23 Aug 2007 12:33:40
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> the "CF Bike Shatters" thread is now too deep for me to follow on my
>>> limited screen real estate - i'm starting a new thread.
>>>
>>> peter cole wrote:
>>>> jim beam wrote:
>>>>> Peter Cole wrote:
>>>>
>>>>>> Find one to support your claim that carbon fibers aren't brittle
>>>>>> & I'll read along.
>>>>>
>>>>> learn about yield before you /dare/ to lecture on deformation,
>>>>> bullshitter.
>>>>
>>>> Oh please. Typical "jim beam" switcharoo. We're talking about
>>>> fracture (see thread title).
>>>
>>> you're confusing fracture of brittle materials with fracture of
>>> ductile materials -
>>
>> I'm not "confusing" them, I'm comparing them.
>
> but you are confusing them - you're not differentiating between ductile
> and brittle - and that's pretty damned fundamental.
You can keep saying that, but I'm not.
>
>>
>>
>>>> Carbon fibers are brittle.
>>>
>>> in isolation, they are. so is any high strength material. but cfrp is
>>> not. what's why we use it!
>>
>> I don't know who "we" is.
>
> prick.
>
>>
>> You're absolutely wrong about CFRP. You can't discuss an inherently
>> anisotropic material without qualifying by fiber orientation (pretty
>> much my whole point).
>
> eh? /you/ are defeating your own argument!!! first you b.s. about
> "isotropic" cfrp, now you're admitting that it's inherently not!!!
Nonsense, read it again.
>
>>
>> A unidirectional fiber composite will have characteristics very much
>> like those of the reinforcing fiber when loaded on-axis. Off-axis,
>> those properties change rapidly,
>
> they don't just "change rapidly", they're completely different. that's
> why it's anisotropic!!!
>
>> becoming essentially those of the matrix at 90 degrees.
>
> mince words whydontcha
Nonsense, read it again.
>
>>
>>>
>>>> They elongate
>>>> only between 0.8 - 1.4% before fracture in tension. E-glass is >3x
>>>> that, 6061 is ~20x that.
>>>
>>> you're mixing apples with oranges. carbon fiber [and glass fiber] have
>>> no deformation mechanism, no dislocation function. so they have no
>>> ductility. so they are "brittle". again, this is not to be confused
>>> with the behavior of their composites.
>>
>> On-axis, the behavior of composite and fiber are very similar.
>
> but composites rarely if ever use solely uniaxial layup. you're trying
> to twist the facts again.
I simply stated a fact.
>>
>>
>>> for glass and carbon, their stress/strain graphs are much extended -
>>
>> Extended from what?
>
> compared to the ductile materials with which you're confused.
>
>>
>>> what would be the hooke's law region of a ductile material.
>>
>> I give up, what?
>
> that wasn't a question. i missed the word "from" - which you'd have
> spotted if you weren't so intent on being a prick.
Your statement is still incoherent.
>>
>>>
>>>> If you have a source (other than yourself)
>>>> that says otherwise, I'm all ears.
>>>
>>> go to a library!
>>> you can also look at this:
>>> http://www.flickr.com/photos/38636024@N00/1208725721/
>>> the "x" points are the "failure" points for all the materials since
>>> onset of yield is failure.
>>
>> Citing yourself again? Why am I not surprised. You're never going to
>> learn anything that way.
>
> prick. /you/ won't admit that you don't understand the difference
> between ductile and brittle. if you won't open a book, then i have to
> show you.
Your diagram has no useful information.
>>>> If you take the often cited 6x ultimate yield strength of CF, derate
>>>> it by the 4 plies (minimum, 0, 90 +-45) you need for isotropy, plus
>>>> the ratio of fiber to epoxy, you come out with nothing special wrt
>>>> overall strength.
>>>
>>> eh? why do you need isotropy??? oh, you're trying to force an
>>> argument where none exists. my bad.
>>
>> No, I'm trying to compare "apples to apples" -- material suitability
>> for isotropic loading.
>
> aha! more fundamental misunderstanding - there's no such thing as
> isotropic loading. that's why we have poisson's ratio.
Now who's mincing words?
>
>>
>>
>>>> That's why there isn't much difference in CF vs Al
>>>> handlebars and seatposts (except price).
>>>
>>> incorrect. it's because it's relatively cheap fiber, relatively
>>> imprecise manufacturing and a generous safety margin.
>>
>> How do you know what the safety margin is?
>> How do you know what the fiber is?
>> How do you know what the process is?
>
> are you denying the facts?
Show me a fact & I'll get back to you on that.
>
>>
>> In the past, you've made the rather obvious point that it's silly to
>> talk about metals without knowing the specific alloy. Now, you're
>> making gross generalizations about a material which has much greater
>> parameterization.
>
> principle apply, big guy.
That's informative!
>> As far as I know, no component or frame manufacturer publishes layup
>> schedules.
>
> they don't quantify, but they do illustrate. you should look some time.
I tried. Why don't you post some of the examples you've found?
>
>> If you have any, please share. You claimed that a "visit to a bike
>> shop" would allow one to learn this.
>
> campy carbon cranks. you can see the exterior layup pattern -
> inconvenient for you to admit though this may be.
>
>
>> I fail to see how visual inspection of a composite part would reveal
>> the layup schedule.
>
> er, because you can see the exterior through the clearcoat? but you wan
> tto talk substrate? well, you'll have to look online, won't you.
>
>
>> At best, you could perhaps get a little information on the outermost
>> ply, often, not even that.
>
> bingo.
That's your idea of a layup schedule?
>>>> It's only when you exploit
>>>> anisotropy that CF makes sense, but then you're stuck with lack of
>>>> impact resistance and brittle failure as a trade off.
>>>
>>> but you have that kind of trade off with /any/ high strength
>>> material, even steel. the higher the strength, the more brittle.
>>
>> You're missing the point about anisotropy.
>
> no i'm not. and that's a spectacular statement from a guy that doesn't
> understand the difference between ductile elongation and brittle fracture.
Repeating that doesn't make it true. You, on the other hand, seem to be
the only one on the planet who doesn't see that CFRP has low impact
resistance.
>>>> CF is great for
>>>> some apps, marginal for others and crappy for the rest. It's an
>>>> engineering thing.
>>>
>>> wow. condescension, massive over-generalization and naivety all in one.
>>
>> No, just engineering basics. With CF bars and posts, you get (more
>> expensive) parts with similar weights. You also get susceptibility to
>> damage from clamping pressure and/or impact. Crappy (yet popular)
>> applications.
>
> so when planes have warning labels on them telling crew not to walk on
> wings, that can be ignored? bullshit. carbon componentry has labels
> saying "do not clamp", "do not exceed...", etc., that can be ignored?
> bullshit.
Who said anything about ignoring labels? I was talking about the need
for labels.
> twist all you want - you're still missing the basics.
If you say so, but do try to scrape up a fact or two & perhaps we can go
from there.
|
| | |
Date: 23 Aug 2007 20:42:22
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> the "CF Bike Shatters" thread is now too deep for me to follow on my
>>>> limited screen real estate - i'm starting a new thread.
>>>>
>>>> peter cole wrote:
>>>>> jim beam wrote:
>>>>>> Peter Cole wrote:
>>>>>
>>>>>>> Find one to support your claim that carbon fibers aren't brittle
>>>>>>> & I'll read along.
>>>>>>
>>>>>> learn about yield before you /dare/ to lecture on deformation,
>>>>>> bullshitter.
>>>>>
>>>>> Oh please. Typical "jim beam" switcharoo. We're talking about
>>>>> fracture (see thread title).
>>>>
>>>> you're confusing fracture of brittle materials with fracture of
>>>> ductile materials -
>>>
>>> I'm not "confusing" them, I'm comparing them.
>>
>> but you are confusing them - you're not differentiating between
>> ductile and brittle - and that's pretty damned fundamental.
>
>
> You can keep saying that, but I'm not.
"6061 elongation is 26%". that's plastic deformation.
"carbon fiber elongation is 1.5%". that's elastic deformation.
there's a fundamental difference an "engineer" should understand.
>
>>
>>>
>>>
>>>>> Carbon fibers are brittle.
>>>>
>>>> in isolation, they are. so is any high strength material. but cfrp is
>>>> not. what's why we use it!
>>>
>>> I don't know who "we" is.
>>
>> prick.
>>
>>>
>>> You're absolutely wrong about CFRP. You can't discuss an inherently
>>> anisotropic material without qualifying by fiber orientation (pretty
>>> much my whole point).
>>
>> eh? /you/ are defeating your own argument!!! first you b.s. about
>> "isotropic" cfrp, now you're admitting that it's inherently not!!!
>
> Nonsense, read it again.
evasive b.s.
>
>>
>>>
>>> A unidirectional fiber composite will have characteristics very much
>>> like those of the reinforcing fiber when loaded on-axis. Off-axis,
>>> those properties change rapidly,
>>
>> they don't just "change rapidly", they're completely different.
>> that's why it's anisotropic!!!
>>
>>> becoming essentially those of the matrix at 90 degrees.
>>
>> mince words whydontcha
>
> Nonsense, read it again.
more evasive b.s.
>
>>
>>>
>>>>
>>>>> They elongate
>>>>> only between 0.8 - 1.4% before fracture in tension. E-glass is >3x
>>>>> that, 6061 is ~20x that.
>>>>
>>>> you're mixing apples with oranges. carbon fiber [and glass fiber] have
>>>> no deformation mechanism, no dislocation function. so they have no
>>>> ductility. so they are "brittle". again, this is not to be confused
>>>> with the behavior of their composites.
>>>
>>> On-axis, the behavior of composite and fiber are very similar.
>>
>> but composites rarely if ever use solely uniaxial layup. you're
>> trying to twist the facts again.
>
> I simply stated a fact.
no, you twisted "facts" to state an untruth.
>
>>>
>>>
>>>> for glass and carbon, their stress/strain graphs are much extended -
>>>
>>> Extended from what?
>>
>> compared to the ductile materials with which you're confused.
>>
>>>
>>>> what would be the hooke's law region of a ductile material.
>>>
>>> I give up, what?
>>
>> that wasn't a question. i missed the word "from" - which you'd have
>> spotted if you weren't so intent on being a prick.
>
> Your statement is still incoherent.
eh? that you don't understand the difference between elastic and
plastic deformation?
>
>
>
>>>
>>>>
>>>>> If you have a source (other than yourself)
>>>>> that says otherwise, I'm all ears.
>>>>
>>>> go to a library!
>>>> you can also look at this:
>>>> http://www.flickr.com/photos/38636024@N00/1208725721/
>>>> the "x" points are the "failure" points for all the materials since
>>>> onset of yield is failure.
>>>
>>> Citing yourself again? Why am I not surprised. You're never going to
>>> learn anything that way.
>>
>> prick. /you/ won't admit that you don't understand the difference
>> between ductile and brittle. if you won't open a book, then i have to
>> show you.
>
> Your diagram has no useful information.
eh? it illustrates different deformation for different materials -
elastic and plastic. something you don't seem to understand.
>
>>>>> If you take the often cited 6x ultimate yield strength of CF, derate
>>>>> it by the 4 plies (minimum, 0, 90 +-45) you need for isotropy, plus
>>>>> the ratio of fiber to epoxy, you come out with nothing special wrt
>>>>> overall strength.
>>>>
>>>> eh? why do you need isotropy??? oh, you're trying to force an
>>>> argument where none exists. my bad.
>>>
>>> No, I'm trying to compare "apples to apples" -- material suitability
>>> for isotropic loading.
>>
>> aha! more fundamental misunderstanding - there's no such thing as
>> isotropic loading. that's why we have poisson's ratio.
>
> Now who's mincing words?
eh? you want me to be more direct? ok. you're an "engineer" that
doesn't know the fundamentals of deformation on loading. that's pretty
fucking weak.
that unmincing enough for you?
>
>
>>
>>>
>>>
>>>>> That's why there isn't much difference in CF vs Al
>>>>> handlebars and seatposts (except price).
>>>>
>>>> incorrect. it's because it's relatively cheap fiber, relatively
>>>> imprecise manufacturing and a generous safety margin.
>>>
>>> How do you know what the safety margin is?
>>> How do you know what the fiber is?
>>> How do you know what the process is?
>>
>> are you denying the facts?
>
> Show me a fact & I'll get back to you on that.
denial. prick.
>
>
>>
>>>
>>> In the past, you've made the rather obvious point that it's silly to
>>> talk about metals without knowing the specific alloy. Now, you're
>>> making gross generalizations about a material which has much greater
>>> parameterization.
>>
>> principle apply, big guy.
>
> That's informative!
from someone that doesn't know basic engineering principles like the
difference between elastic and plastic, that's a real dumb-ass statement.
>
>
>
>>> As far as I know, no component or frame manufacturer publishes layup
>>> schedules.
>>
>> they don't quantify, but they do illustrate. you should look some time.
>
> I tried. Why don't you post some of the examples you've found?
why do i have to do all the heavy lifting??? you're the prick
contesting the issue.
>
>
>>
>>> If you have any, please share. You claimed that a "visit to a bike
>>> shop" would allow one to learn this.
>>
>> campy carbon cranks. you can see the exterior layup pattern -
>> inconvenient for you to admit though this may be.
>>
>>
>>> I fail to see how visual inspection of a composite part would reveal
>>> the layup schedule.
>>
>> er, because you can see the exterior through the clearcoat? but you
>> wan tto talk substrate? well, you'll have to look online, won't you.
>>
>>
>>> At best, you could perhaps get a little information on the outermost
>>> ply, often, not even that.
>>
>> bingo.
>
> That's your idea of a layup schedule?
no. but you're my idea of an evasive prick.
>
>
>>>>> It's only when you exploit
>>>>> anisotropy that CF makes sense, but then you're stuck with lack of
>>>>> impact resistance and brittle failure as a trade off.
>>>>
>>>> but you have that kind of trade off with /any/ high strength
>>>> material, even steel. the higher the strength, the more brittle.
>>>
>>> You're missing the point about anisotropy.
>>
>> no i'm not. and that's a spectacular statement from a guy that
>> doesn't understand the difference between ductile elongation and
>> brittle fracture.
>
> Repeating that doesn't make it true.
no, being true makes it true. repeating denial can't make it untrue.
> You, on the other hand, seem to be
> the only one on the planet who doesn't see that CFRP has low impact
> resistance.
bullshit.
1. who the fuck wants their frame to be resistant to artillery fire.
2. "impact resistance" is a function of the fiber itself, the layup, the
fiber length, density, orientation and matrix - among other things.
"CFRP has low impact resistance" is such a BULLSHIT dumb-ass statement,
it beggars belief.
>
>>>>> CF is great for
>>>>> some apps, marginal for others and crappy for the rest. It's an
>>>>> engineering thing.
>>>>
>>>> wow. condescension, massive over-generalization and naivety all in
>>>> one.
>>>
>>> No, just engineering basics. With CF bars and posts, you get (more
>>> expensive) parts with similar weights. You also get susceptibility to
>>> damage from clamping pressure and/or impact. Crappy (yet popular)
>>> applications.
>>
>> so when planes have warning labels on them telling crew not to walk on
>> wings, that can be ignored? bullshit. carbon componentry has labels
>> saying "do not clamp", "do not exceed...", etc., that can be ignored?
>> bullshit.
>
> Who said anything about ignoring labels? I was talking about the need
> for labels.
so what would your labels say then? "er, this may be elastic or it may
be plastic - we really don't know"?
>
>> twist all you want - you're still missing the basics.
>
> If you say so,
damned right i say so!
> but do try to scrape up a fact or two & perhaps we can go
> from there.
i have. but you seem too intent on being a persistently ignorant prick
to absorb anything.
|
| | | |
Date: 25 Aug 2007 16:57:16
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>>>> the "CF Bike Shatters" thread is now too deep for me to follow on my
>>>>> limited screen real estate - i'm starting a new thread.
>>>>>
>>>>> peter cole wrote:
>>>>>> jim beam wrote:
>>>>>>> Peter Cole wrote:
>>>>>>
>>>>>>>> Find one to support your claim that carbon fibers aren't brittle
>>>>>>>> & I'll read along.
>>>>>>>
>>>>>>> learn about yield before you /dare/ to lecture on deformation,
>>>>>>> bullshitter.
>>>>>>
>>>>>> Oh please. Typical "jim beam" switcharoo. We're talking about
>>>>>> fracture (see thread title).
>>>>>
>>>>> you're confusing fracture of brittle materials with fracture of
>>>>> ductile materials -
>>>>
>>>> I'm not "confusing" them, I'm comparing them.
>>>
>>> but you are confusing them - you're not differentiating between
>>> ductile and brittle - and that's pretty damned fundamental.
>>
>>
>> You can keep saying that, but I'm not.
>
> "6061 elongation is 26%". that's plastic deformation.
> "carbon fiber elongation is 1.5%". that's elastic deformation.
>
> there's a fundamental difference an "engineer" should understand.
Yes, that's obvious. Who said it wasn't?
You don't have to put quotes around engineer.
>
>
>>
>>>
>>>>
>>>>
>>>>>> Carbon fibers are brittle.
>>>>>
>>>>> in isolation, they are. so is any high strength material. but
>>>>> cfrp is
>>>>> not. what's why we use it!
>>>>
>>>> I don't know who "we" is.
>>>
>>> prick.
>>>
>>>>
>>>> You're absolutely wrong about CFRP. You can't discuss an inherently
>>>> anisotropic material without qualifying by fiber orientation (pretty
>>>> much my whole point).
>>>
>>> eh? /you/ are defeating your own argument!!! first you b.s. about
>>> "isotropic" cfrp, now you're admitting that it's inherently not!!!
>>
>> Nonsense, read it again.
>
> evasive b.s.
You can't discuss CFRP without layup schedule. Uniaxial CFRP has
impressive numbers -- in one direction.
>>
>>>
>>>>
>>>> A unidirectional fiber composite will have characteristics very much
>>>> like those of the reinforcing fiber when loaded on-axis. Off-axis,
>>>> those properties change rapidly,
>>>
>>> they don't just "change rapidly", they're completely different.
>>> that's why it's anisotropic!!!
>>>
>>>> becoming essentially those of the matrix at 90 degrees.
>>>
>>> mince words whydontcha
>>
>> Nonsense, read it again.
>
> more evasive b.s.
If you take the trouble to look at the stress-strain of uniaxial CFRP as
the load angle changes, all will become clear.
>
>>
>>>
>>>>
>>>>>
>>>>>> They elongate
>>>>>> only between 0.8 - 1.4% before fracture in tension. E-glass is >3x
>>>>>> that, 6061 is ~20x that.
>>>>>
>>>>> you're mixing apples with oranges. carbon fiber [and glass fiber]
>>>>> have
>>>>> no deformation mechanism, no dislocation function. so they have no
>>>>> ductility. so they are "brittle". again, this is not to be confused
>>>>> with the behavior of their composites.
>>>>
>>>> On-axis, the behavior of composite and fiber are very similar.
>>>
>>> but composites rarely if ever use solely uniaxial layup. you're
>>> trying to twist the facts again.
>>
>> I simply stated a fact.
>
> no, you twisted "facts" to state an untruth.
Composite will be as brittle as it is strong. Try to understand that.
>>
>>>>
>>>>
>>>>> for glass and carbon, their stress/strain graphs are much extended -
>>>>
>>>> Extended from what?
>>>
>>> compared to the ductile materials with which you're confused.
>>>
>>>>
>>>>> what would be the hooke's law region of a ductile material.
>>>>
>>>> I give up, what?
>>>
>>> that wasn't a question. i missed the word "from" - which you'd have
>>> spotted if you weren't so intent on being a prick.
>>
>> Your statement is still incoherent.
>
> eh? that you don't understand the difference between elastic and
> plastic deformation?
>
I certainly do, it's not so very hard to grasp.
>>
>>
>>
>>>>
>>>>>
>>>>>> If you have a source (other than yourself)
>>>>>> that says otherwise, I'm all ears.
>>>>>
>>>>> go to a library!
>>>>> you can also look at this:
>>>>> http://www.flickr.com/photos/38636024@N00/1208725721/
>>>>> the "x" points are the "failure" points for all the materials since
>>>>> onset of yield is failure.
>>>>
>>>> Citing yourself again? Why am I not surprised. You're never going to
>>>> learn anything that way.
>>>
>>> prick. /you/ won't admit that you don't understand the difference
>>> between ductile and brittle. if you won't open a book, then i have
>>> to show you.
>>
>> Your diagram has no useful information.
>
> eh? it illustrates different deformation for different materials -
> elastic and plastic. something you don't seem to understand.
It's not to scale, it attempts to depict fiber rather than composite. It
still doesn't explain why you disagree with the rest of the world about
CF composite being brittle.
>
>
>>
>>>>>> If you take the often cited 6x ultimate yield strength of CF, derate
>>>>>> it by the 4 plies (minimum, 0, 90 +-45) you need for isotropy, plus
>>>>>> the ratio of fiber to epoxy, you come out with nothing special wrt
>>>>>> overall strength.
>>>>>
>>>>> eh? why do you need isotropy??? oh, you're trying to force an
>>>>> argument where none exists. my bad.
>>>>
>>>> No, I'm trying to compare "apples to apples" -- material suitability
>>>> for isotropic loading.
>>>
>>> aha! more fundamental misunderstanding - there's no such thing as
>>> isotropic loading. that's why we have poisson's ratio.
>>
>> Now who's mincing words?
>
> eh? you want me to be more direct? ok. you're an "engineer" that
> doesn't know the fundamentals of deformation on loading. that's pretty
> fucking weak.
>
> that unmincing enough for you?
That's lovely (in sentiment) but unfortunately still incoherent.
>>
>>
>>>
>>>>
>>>>
>>>>>> That's why there isn't much difference in CF vs Al
>>>>>> handlebars and seatposts (except price).
>>>>>
>>>>> incorrect. it's because it's relatively cheap fiber, relatively
>>>>> imprecise manufacturing and a generous safety margin.
>>>>
>>>> How do you know what the safety margin is?
>>>> How do you know what the fiber is?
>>>> How do you know what the process is?
>>>
>>> are you denying the facts?
>>
>> Show me a fact & I'll get back to you on that.
>
> denial. prick.
I do hope you get help with your Tourette's, meanwhile, got any facts?
>>>>
>>>> In the past, you've made the rather obvious point that it's silly to
>>>> talk about metals without knowing the specific alloy. Now, you're
>>>> making gross generalizations about a material which has much greater
>>>> parameterization.
>>>
>>> principle apply, big guy.
>>
>> That's informative!
>
> from someone that doesn't know basic engineering principles like the
> difference between elastic and plastic, that's a real dumb-ass statement.
OK, what "principle"?
>
>
>>
>>
>>
>>>> As far as I know, no component or frame manufacturer publishes layup
>>>> schedules.
>>>
>>> they don't quantify, but they do illustrate. you should look some time.
>>
>> I tried. Why don't you post some of the examples you've found?
>
> why do i have to do all the heavy lifting??? you're the prick
> contesting the issue.
I didn't think you had any. Given that they're all proprietary, that
would have been impressive. So just go on in through-your-hat mode (I'm
much too polite to use the obvious term).
>>>
>>>> If you have any, please share. You claimed that a "visit to a bike
>>>> shop" would allow one to learn this.
>>>
>>> campy carbon cranks. you can see the exterior layup pattern -
>>> inconvenient for you to admit though this may be.
>>>
>>>
>>>> I fail to see how visual inspection of a composite part would reveal
>>>> the layup schedule.
>>>
>>> er, because you can see the exterior through the clearcoat? but you
>>> wan tto talk substrate? well, you'll have to look online, won't you.
Show me a link, & I'll be right over.
>>>
>>>
>>>> At best, you could perhaps get a little information on the outermost
>>>> ply, often, not even that.
>>>
>>> bingo.
>>
>> That's your idea of a layup schedule?
>
> no. but you're my idea of an evasive prick.
What about layup schedule (I already know your opinion of me)?
>
>>
>>
>>>>>> It's only when you exploit
>>>>>> anisotropy that CF makes sense, but then you're stuck with lack of
>>>>>> impact resistance and brittle failure as a trade off.
>>>>>
>>>>> but you have that kind of trade off with /any/ high strength
>>>>> material, even steel. the higher the strength, the more brittle.
>>>>
>>>> You're missing the point about anisotropy.
>>>
>>> no i'm not. and that's a spectacular statement from a guy that
>>> doesn't understand the difference between ductile elongation and
>>> brittle fracture.
>>
>> Repeating that doesn't make it true.
>
> no, being true makes it true. repeating denial can't make it untrue.
>
>
>> You, on the other hand, seem to be the only one on the planet who
>> doesn't see that CFRP has low impact resistance.
>
> bullshit.
>
> 1. who the fuck wants their frame to be resistant to artillery fire.
> 2. "impact resistance" is a function of the fiber itself, the layup, the
> fiber length, density, orientation and matrix - among other things.
> "CFRP has low impact resistance" is such a BULLSHIT dumb-ass statement,
> it beggars belief.
Then why does everyone believe it but you?
>>
>>>>>> CF is great for
>>>>>> some apps, marginal for others and crappy for the rest. It's an
>>>>>> engineering thing.
>>>>>
>>>>> wow. condescension, massive over-generalization and naivety all in
>>>>> one.
>>>>
>>>> No, just engineering basics. With CF bars and posts, you get (more
>>>> expensive) parts with similar weights. You also get susceptibility
>>>> to damage from clamping pressure and/or impact. Crappy (yet popular)
>>>> applications.
>>>
>>> so when planes have warning labels on them telling crew not to walk
>>> on wings, that can be ignored? bullshit. carbon componentry has
>>> labels saying "do not clamp", "do not exceed...", etc., that can be
>>> ignored? bullshit.
>>
>> Who said anything about ignoring labels? I was talking about the need
>> for labels.
>
> so what would your labels say then? "er, this may be elastic or it may
> be plastic - we really don't know"?
That does not even make a shred of sense.
>>
>>> twist all you want - you're still missing the basics.
>>
>> If you say so,
>
> damned right i say so!
>
> > but do try to scrape up a fact or two & perhaps we can go
>> from there.
>
> i have. but you seem too intent on being a persistently ignorant prick
> to absorb anything.
I have yet to see a fact, only "jim beam"-ish self-cites. Perhaps
they're the same in your world, but not in the much bigger world the
rest of us live in.
|
| | | | |
Date: 25 Aug 2007 18:20:16
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>>>> the "CF Bike Shatters" thread is now too deep for me to follow on my
>>>>>> limited screen real estate - i'm starting a new thread.
>>>>>>
>>>>>> peter cole wrote:
>>>>>>> jim beam wrote:
>>>>>>>> Peter Cole wrote:
>>>>>>>
>>>>>>>>> Find one to support your claim that carbon fibers aren't brittle
>>>>>>>>> & I'll read along.
>>>>>>>>
>>>>>>>> learn about yield before you /dare/ to lecture on deformation,
>>>>>>>> bullshitter.
>>>>>>>
>>>>>>> Oh please. Typical "jim beam" switcharoo. We're talking about
>>>>>>> fracture (see thread title).
>>>>>>
>>>>>> you're confusing fracture of brittle materials with fracture of
>>>>>> ductile materials -
>>>>>
>>>>> I'm not "confusing" them, I'm comparing them.
>>>>
>>>> but you are confusing them - you're not differentiating between
>>>> ductile and brittle - and that's pretty damned fundamental.
>>>
>>>
>>> You can keep saying that, but I'm not.
>>
>> "6061 elongation is 26%". that's plastic deformation.
>> "carbon fiber elongation is 1.5%". that's elastic deformation.
>>
>> there's a fundamental difference an "engineer" should understand.
>
>
> Yes, that's obvious. Who said it wasn't?
anyone mistaking plastic elongation for plastic elongation /clearly/
doesn't find the distinction "obvious".
>
> You don't have to put quotes around engineer.
you do if it's a name someone calls themselves, but doesn't evidence
qualification.
>
>
>>
>>
>>>
>>>>
>>>>>
>>>>>
>>>>>>> Carbon fibers are brittle.
>>>>>>
>>>>>> in isolation, they are. so is any high strength material. but
>>>>>> cfrp is
>>>>>> not. what's why we use it!
>>>>>
>>>>> I don't know who "we" is.
>>>>
>>>> prick.
>>>>
>>>>>
>>>>> You're absolutely wrong about CFRP. You can't discuss an inherently
>>>>> anisotropic material without qualifying by fiber orientation
>>>>> (pretty much my whole point).
>>>>
>>>> eh? /you/ are defeating your own argument!!! first you b.s. about
>>>> "isotropic" cfrp, now you're admitting that it's inherently not!!!
>>>
>>> Nonsense, read it again.
>>
>> evasive b.s.
>
> You can't discuss CFRP without layup schedule. Uniaxial CFRP has
> impressive numbers -- in one direction.
"in one direction" indeed. so why bleat about isotropy as if it's a
base property? because you're bullshitting and trying to muddy the
water, that's why!
>
>
>>>
>>>>
>>>>>
>>>>> A unidirectional fiber composite will have characteristics very
>>>>> much like those of the reinforcing fiber when loaded on-axis.
>>>>> Off-axis, those properties change rapidly,
>>>>
>>>> they don't just "change rapidly", they're completely different.
>>>> that's why it's anisotropic!!!
>>>>
>>>>> becoming essentially those of the matrix at 90 degrees.
>>>>
>>>> mince words whydontcha
>>>
>>> Nonsense, read it again.
>>
>> more evasive b.s.
>
> If you take the trouble to look at the stress-strain of uniaxial CFRP as
> the load angle changes, all will become clear.
says the guy that bullshits about elongation while getting confused
between plastic and elastic deformation...
>
>
>>
>>>
>>>>
>>>>>
>>>>>>
>>>>>>> They elongate
>>>>>>> only between 0.8 - 1.4% before fracture in tension. E-glass is >3x
>>>>>>> that, 6061 is ~20x that.
>>>>>>
>>>>>> you're mixing apples with oranges. carbon fiber [and glass fiber]
>>>>>> have
>>>>>> no deformation mechanism, no dislocation function. so they have no
>>>>>> ductility. so they are "brittle". again, this is not to be confused
>>>>>> with the behavior of their composites.
>>>>>
>>>>> On-axis, the behavior of composite and fiber are very similar.
>>>>
>>>> but composites rarely if ever use solely uniaxial layup. you're
>>>> trying to twist the facts again.
>>>
>>> I simply stated a fact.
>>
>> no, you twisted "facts" to state an untruth.
>
> Composite will be as brittle as it is strong. Try to understand that.
!!! sure! there measured in the same units too aren't they!!!
>
>
>>>
>>>>>
>>>>>
>>>>>> for glass and carbon, their stress/strain graphs are much extended -
>>>>>
>>>>> Extended from what?
>>>>
>>>> compared to the ductile materials with which you're confused.
>>>>
>>>>>
>>>>>> what would be the hooke's law region of a ductile material.
>>>>>
>>>>> I give up, what?
>>>>
>>>> that wasn't a question. i missed the word "from" - which you'd have
>>>> spotted if you weren't so intent on being a prick.
>>>
>>> Your statement is still incoherent.
>>
>> eh? that you don't understand the difference between elastic and
>> plastic deformation?
>>
>
> I certainly do, it's not so very hard to grasp.
so why the painful confusion between plastic and elastic? stupidity?
or deliberate bullshit?
>
>
>>>
>>>
>>>
>>>>>
>>>>>>
>>>>>>> If you have a source (other than yourself)
>>>>>>> that says otherwise, I'm all ears.
>>>>>>
>>>>>> go to a library!
>>>>>> you can also look at this:
>>>>>> http://www.flickr.com/photos/38636024@N00/1208725721/
>>>>>> the "x" points are the "failure" points for all the materials
>>>>>> since onset of yield is failure.
>>>>>
>>>>> Citing yourself again? Why am I not surprised. You're never going
>>>>> to learn anything that way.
>>>>
>>>> prick. /you/ won't admit that you don't understand the difference
>>>> between ductile and brittle. if you won't open a book, then i have
>>>> to show you.
>>>
>>> Your diagram has no useful information.
>>
>> eh? it illustrates different deformation for different materials -
>> elastic and plastic. something you don't seem to understand.
>
> It's not to scale, it attempts to depict fiber rather than composite. It
> still doesn't explain why you disagree with the rest of the world about
> CF composite being brittle.
1. what part of the label stating "NOT TO SCALE" is confusing to you???
2. composites have properties intermediate between the fiber and the
matrix, depending on composition.
3. bullshit statements that "carbon is brittle" is as misleading as it
is wrong.
>
>
>>
>>
>>>
>>>>>>> If you take the often cited 6x ultimate yield strength of CF, derate
>>>>>>> it by the 4 plies (minimum, 0, 90 +-45) you need for isotropy, plus
>>>>>>> the ratio of fiber to epoxy, you come out with nothing special wrt
>>>>>>> overall strength.
>>>>>>
>>>>>> eh? why do you need isotropy??? oh, you're trying to force an
>>>>>> argument where none exists. my bad.
>>>>>
>>>>> No, I'm trying to compare "apples to apples" -- material
>>>>> suitability for isotropic loading.
>>>>
>>>> aha! more fundamental misunderstanding - there's no such thing as
>>>> isotropic loading. that's why we have poisson's ratio.
>>>
>>> Now who's mincing words?
>>
>> eh? you want me to be more direct? ok. you're an "engineer" that
>> doesn't know the fundamentals of deformation on loading. that's
>> pretty fucking weak.
>>
>> that unmincing enough for you?
>
> That's lovely (in sentiment) but unfortunately still incoherent.
/your/ confusion between elastic and plastic is incoherent buddy.
>
>
>>>
>>>
>>>>
>>>>>
>>>>>
>>>>>>> That's why there isn't much difference in CF vs Al
>>>>>>> handlebars and seatposts (except price).
>>>>>>
>>>>>> incorrect. it's because it's relatively cheap fiber, relatively
>>>>>> imprecise manufacturing and a generous safety margin.
>>>>>
>>>>> How do you know what the safety margin is?
>>>>> How do you know what the fiber is?
>>>>> How do you know what the process is?
>>>>
>>>> are you denying the facts?
>>>
>>> Show me a fact & I'll get back to you on that.
>>
>> denial. prick.
>
> I do hope you get help with your Tourette's, meanwhile, got any facts?
fuck you, prick. you've already got facts of principle. what you're
bleating about is numbers. but you're no stranger to deliberate
muddying of the water are you.
>
>
>>>>>
>>>>> In the past, you've made the rather obvious point that it's silly
>>>>> to talk about metals without knowing the specific alloy. Now,
>>>>> you're making gross generalizations about a material which has much
>>>>> greater parameterization.
>>>>
>>>> principle apply, big guy.
>>>
>>> That's informative!
>>
>> from someone that doesn't know basic engineering principles like the
>> difference between elastic and plastic, that's a real dumb-ass statement.
>
>
> OK, what "principle"?
er, how about we start with "elastic is not plastic"?
>
>
>>
>>
>>>
>>>
>>>
>>>>> As far as I know, no component or frame manufacturer publishes
>>>>> layup schedules.
>>>>
>>>> they don't quantify, but they do illustrate. you should look some
>>>> time.
>>>
>>> I tried. Why don't you post some of the examples you've found?
>>
>> why do i have to do all the heavy lifting??? you're the prick
>> contesting the issue.
>
> I didn't think you had any.
bullshit.
> Given that they're all proprietary,
bullshit! spectacular avoidance!!!
> that
> would have been impressive. So just go on in through-your-hat mode (I'm
> much too polite to use the obvious term).
oh, please, let me - you're a prick, "mr. engineer".
>
>
>>>>
>>>>> If you have any, please share. You claimed that a "visit to a bike
>>>>> shop" would allow one to learn this.
>>>>
>>>> campy carbon cranks. you can see the exterior layup pattern -
>>>> inconvenient for you to admit though this may be.
>>>>
>>>>
>>>>> I fail to see how visual inspection of a composite part would
>>>>> reveal the layup schedule.
>>>>
>>>> er, because you can see the exterior through the clearcoat? but you
>>>> wan tto talk substrate? well, you'll have to look online, won't you.
>
> Show me a link, & I'll be right over.
no, you get your deceitful ass on over to a shop.
>
>
>
>>>>
>>>>
>>>>> At best, you could perhaps get a little information on the
>>>>> outermost ply, often, not even that.
>>>>
>>>> bingo.
>>>
>>> That's your idea of a layup schedule?
>>
>> no. but you're my idea of an evasive prick.
>
> What about layup schedule (I already know your opinion of me)?
see above.
>
>
>
>>
>>>
>>>
>>>>>>> It's only when you exploit
>>>>>>> anisotropy that CF makes sense, but then you're stuck with lack of
>>>>>>> impact resistance and brittle failure as a trade off.
>>>>>>
>>>>>> but you have that kind of trade off with /any/ high strength
>>>>>> material, even steel. the higher the strength, the more brittle.
>>>>>
>>>>> You're missing the point about anisotropy.
>>>>
>>>> no i'm not. and that's a spectacular statement from a guy that
>>>> doesn't understand the difference between ductile elongation and
>>>> brittle fracture.
>>>
>>> Repeating that doesn't make it true.
>>
>> no, being true makes it true. repeating denial can't make it untrue.
>>
>>
>>> You, on the other hand, seem to be the only one on the planet who
>>> doesn't see that CFRP has low impact resistance.
>>
>> bullshit.
>>
>> 1. who the fuck wants their frame to be resistant to artillery fire.
>> 2. "impact resistance" is a function of the fiber itself, the layup,
>> the fiber length, density, orientation and matrix - among other
>> things. "CFRP has low impact resistance" is such a BULLSHIT dumb-ass
>> statement, it beggars belief.
>
> Then why does everyone believe it but you?
not everyone knows or cares. but that's why you muddy the water - so
you can keep on bullshitting.
>
>
>
>>>
>>>>>>> CF is great for
>>>>>>> some apps, marginal for others and crappy for the rest. It's an
>>>>>>> engineering thing.
>>>>>>
>>>>>> wow. condescension, massive over-generalization and naivety all
>>>>>> in one.
>>>>>
>>>>> No, just engineering basics. With CF bars and posts, you get (more
>>>>> expensive) parts with similar weights. You also get susceptibility
>>>>> to damage from clamping pressure and/or impact. Crappy (yet
>>>>> popular) applications.
>>>>
>>>> so when planes have warning labels on them telling crew not to walk
>>>> on wings, that can be ignored? bullshit. carbon componentry has
>>>> labels saying "do not clamp", "do not exceed...", etc., that can be
>>>> ignored? bullshit.
>>>
>>> Who said anything about ignoring labels? I was talking about the need
>>> for labels.
>>
>> so what would your labels say then? "er, this may be elastic or it
>> may be plastic - we really don't know"?
>
> That does not even make a shred of sense.
not knowing the distinction between the two deformation regimes you
mean? agreed - makes ZERO sense for anyone purporting to be an engineer.
>
>>>
>>>> twist all you want - you're still missing the basics.
>>>
>>> If you say so,
>>
>> damned right i say so!
>>
>> > but do try to scrape up a fact or two & perhaps we can go
>>> from there.
>>
>> i have. but you seem too intent on being a persistently ignorant
>> prick to absorb anything.
>
> I have yet to see a fact, only "jim beam"-ish self-cites. Perhaps
> they're the same in your world, but not in the much bigger world the
> rest of us live in.
that's such a crock. you don't know basic deformation theory and yet
base claims of denial on this fundamental ignorance. and when
confronted with fact, you deny. but all the while, you play to the
peanut gallery like you're the victim with this classic
passive-aggressive bullshit. you're a complete prick.
|
| | | | | |
Date: 27 Aug 2007 19:10:18
From: Tom \Johnny Sunset\ Sherman
Subject: Re: "CF Bike Shatters" - continued
|
jim beam aka evan williams wrote:
> ...
> anyone mistaking plastic elongation for plastic elongation /clearly/
> doesn't find the distinction "obvious".
Gee, truisms are false? I always thought that "plastic elongation" was
the same as "plastic elongation".
> ...ZERO....
HIS KEYBOARD DOES HAVE CAPITAL LETTERS!
--
Tom Sherman - Holstein-Friesland Bovinia
--
Posted via a free Usenet account from http://www.teranews.com
|
| | | | | | |
Date: 27 Aug 2007 20:11:38
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Tom "Johnny Sunset" Sherman wrote:
> jim beam aka evan williams wrote:
>> ...
>> anyone mistaking plastic elongation for plastic elongation /clearly/
>> doesn't find the distinction "obvious".
>
> Gee, truisms are false? I always thought that "plastic elongation" was
> the same as "plastic elongation".
that's a typo. and you know it.
>
>> ...ZERO....
>
> HIS KEYBOARD DOES HAVE CAPITAL LETTERS!
>
genius.
|
| | | | | |
Date: 26 Aug 2007 09:30:40
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> that's such a crock. you don't know basic deformation theory and yet
> base claims of denial on this fundamental ignorance. and when
> confronted with fact, you deny. but all the while, you play to the
> peanut gallery like you're the victim with this classic
> passive-aggressive bullshit. you're a complete prick.
Let's drop all the infantile name calling and cut to the chase, shall
we? Your claim that CF composite is not brittle is contrary to every
source I have seen, to say that yours is a minority viewpoint would be
to give it too much credit. You're dead wrong and only resort to this
nonsense to try to bluff your way out. Nobody's buying it.
|
| | | | | | |
Date: 26 Aug 2007 07:35:16
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>
>> that's such a crock. you don't know basic deformation theory and yet
>> base claims of denial on this fundamental ignorance. and when
>> confronted with fact, you deny. but all the while, you play to the
>> peanut gallery like you're the victim with this classic
>> passive-aggressive bullshit. you're a complete prick.
>
> Let's drop all the infantile name calling and cut to the chase, shall
> we? Your claim that CF composite is not brittle is contrary to every
> source I have seen, to say that yours is a minority viewpoint would be
> to give it too much credit. You're dead wrong and only resort to this
> nonsense to try to bluff your way out. Nobody's buying it.
what's your source? conan o'brien's mom?
carbon composites are not brittle like glass is brittle, which is what
you seem to want us to believe. "brittle" is defined by energy
absorption on fracture and the deformation mechanism.
|
| | | | | | | |
Date: 27 Aug 2007 09:47:12
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>
>>> that's such a crock. you don't know basic deformation theory and yet
>>> base claims of denial on this fundamental ignorance. and when
>>> confronted with fact, you deny. but all the while, you play to the
>>> peanut gallery like you're the victim with this classic
>>> passive-aggressive bullshit. you're a complete prick.
>>
>> Let's drop all the infantile name calling and cut to the chase, shall
>> we? Your claim that CF composite is not brittle is contrary to every
>> source I have seen, to say that yours is a minority viewpoint would be
>> to give it too much credit. You're dead wrong and only resort to this
>> nonsense to try to bluff your way out. Nobody's buying it.
>
> what's your source? conan o'brien's mom?
>
> carbon composites are not brittle like glass is brittle, which is what
> you seem to want us to believe. "brittle" is defined by energy
> absorption on fracture and the deformation mechanism.
Oh, please -- now the "ad absurdum" approach. No one is claiming a CF
composite plate or tube is like a glass plate or tube, or that a CF bike
is like one made of glass. The comparison is to other materials commonly
used for bicycle/component manufacture -- steel, aluminum and
titanium. In comparison to those materials, CF is indeed brittle, and
has much lower impact resistance.
<http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites >
The main disadvantage of carbon (graphite) fibers is catastrophic mode
of failure (carbon fibers are brittle).
Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
following properties:
*
Light weight;
*
High strength-to-weight ratio;
*
Very High modulus elasticity-to-weight ratio;
*
High Fatigue strength;
*
Good corrosion resistance;
*
Very low coefficient of thermal expansion;
*
Low impact resistance;
*
High electric conductivity;
*
High cost.
<http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566 >
"The studies with the carbon fiber composites reveal the brittle nature
of this material, particularly when compared to the glass fiber composites."
<http://en.wikipedia.org/wiki/Tensile_strength >
"Brittle materials such as concrete and carbon fiber do not have a yield
point, and do not strain-harden which means that the ultimate strength
and breaking strength are the same. A most unusual stress-strain curve
is shown in the figure below. Typical brittle materials do not show any
plastic deformation but fail while the deformation is elastic. One of
the characteristics of a brittle failure is that the two broken parts
can be reassembled to produce the same shape as the original component.
A typical stress strain curve for a brittle material will be linear."
<http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html >
"The outstanding design properties of carbon fiber/resin matrix
composites are their high strength-to-weight and stiffness-to-weight
ratios. With proper selection and placement of fibers, the composites
can be stronger and stiffer than equivalent thickness steel parts and
weigh 40 to 70% less. Fatigue resistance of continuous-fiber composites
is excellent, and chemical resistance is better than that of
glass-reinforced systems, particularly in alkaline environments. Like
most rigid materials, however, carbon-fiber composites are relatively
brittle. The composites have no yield behavior, and resistance to impact
is low."
A rather good primer:
<http://www.advancedcomposites.com/technology.htm >
Says what I have been saying:
"The primary advantage of composite materials over more conventional
metallic or polymeric materials is their anisotropic mechanical
response. This resulting directionality is carefully used to advantage."
And:
"Figures 11. and 12. Illustrate how dramatically the properties of
plus/minus angle laminates change versus angle."
Also an overview of failure mechanisms.
|
| | | | | | | | |
Date: 27 Aug 2007 20:11:07
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>
>>>> that's such a crock. you don't know basic deformation theory and
>>>> yet base claims of denial on this fundamental ignorance. and when
>>>> confronted with fact, you deny. but all the while, you play to the
>>>> peanut gallery like you're the victim with this classic
>>>> passive-aggressive bullshit. you're a complete prick.
>>>
>>> Let's drop all the infantile name calling and cut to the chase, shall
>>> we? Your claim that CF composite is not brittle is contrary to every
>>> source I have seen, to say that yours is a minority viewpoint would
>>> be to give it too much credit. You're dead wrong and only resort to
>>> this nonsense to try to bluff your way out. Nobody's buying it.
>>
>> what's your source? conan o'brien's mom?
>>
>> carbon composites are not brittle like glass is brittle, which is what
>> you seem to want us to believe. "brittle" is defined by energy
>> absorption on fracture and the deformation mechanism.
>
> Oh, please -- now the "ad absurdum" approach. No one is claiming a CF
> composite plate or tube is like a glass plate or tube, or that a CF bike
> is like one made of glass. The comparison is to other materials commonly
> used for bicycle/component manufacture -- steel, aluminum and titanium.
> In comparison to those materials, CF is indeed brittle, and has much
> lower impact resistance.
>
> <http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites>
>
>
> The main disadvantage of carbon (graphite) fibers is catastrophic mode
> of failure (carbon fibers are brittle).
>
> Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
> following properties:
>
> *
> Light weight;
> *
> High strength-to-weight ratio;
> *
> Very High modulus elasticity-to-weight ratio;
> *
> High Fatigue strength;
> *
> Good corrosion resistance;
> *
> Very low coefficient of thermal expansion;
> *
> Low impact resistance;
> *
> High electric conductivity;
> *
> High cost.
>
> <http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566>
>
>
> "The studies with the carbon fiber composites reveal the brittle nature
> of this material, particularly when compared to the glass fiber
> composites."
>
> <http://en.wikipedia.org/wiki/Tensile_strength>
>
> "Brittle materials such as concrete and carbon fiber do not have a yield
> point, and do not strain-harden which means that the ultimate strength
> and breaking strength are the same. A most unusual stress-strain curve
> is shown in the figure below. Typical brittle materials do not show any
> plastic deformation but fail while the deformation is elastic. One of
> the characteristics of a brittle failure is that the two broken parts
> can be reassembled to produce the same shape as the original component.
> A typical stress strain curve for a brittle material will be linear."
>
> <http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html>
>
> "The outstanding design properties of carbon fiber/resin matrix
> composites are their high strength-to-weight and stiffness-to-weight
> ratios. With proper selection and placement of fibers, the composites
> can be stronger and stiffer than equivalent thickness steel parts and
> weigh 40 to 70% less. Fatigue resistance of continuous-fiber composites
> is excellent, and chemical resistance is better than that of
> glass-reinforced systems, particularly in alkaline environments. Like
> most rigid materials, however, carbon-fiber composites are relatively
> brittle. The composites have no yield behavior, and resistance to impact
> is low."
>
> A rather good primer:
> <http://www.advancedcomposites.com/technology.htm>
>
> Says what I have been saying:
>
> "The primary advantage of composite materials over more conventional
> metallic or polymeric materials is their anisotropic mechanical
> response. This resulting directionality is carefully used to advantage."
>
> And:
> "Figures 11. and 12. Illustrate how dramatically the properties of
> plus/minus angle laminates change versus angle."
>
> Also an overview of failure mechanisms.
ah, the peter cole approach: "keep trying to baffle them with bull".
since this is the fundamental intellectual hurdle you can't seem to
overcome, let's cut to the point - you go ahead and define "brittle".
and /please/ try not to deceive by citing anisotropy as evidence. thank
you.
|
| | | | | | | | | |
Date: 28 Aug 2007 07:42:30
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>>>
>>>>> that's such a crock. you don't know basic deformation theory and
>>>>> yet base claims of denial on this fundamental ignorance. and when
>>>>> confronted with fact, you deny. but all the while, you play to the
>>>>> peanut gallery like you're the victim with this classic
>>>>> passive-aggressive bullshit. you're a complete prick.
>>>>
>>>> Let's drop all the infantile name calling and cut to the chase,
>>>> shall we? Your claim that CF composite is not brittle is contrary to
>>>> every source I have seen, to say that yours is a minority viewpoint
>>>> would be to give it too much credit. You're dead wrong and only
>>>> resort to this nonsense to try to bluff your way out. Nobody's
>>>> buying it.
>>>
>>> what's your source? conan o'brien's mom?
>>>
>>> carbon composites are not brittle like glass is brittle, which is
>>> what you seem to want us to believe. "brittle" is defined by energy
>>> absorption on fracture and the deformation mechanism.
>>
>> Oh, please -- now the "ad absurdum" approach. No one is claiming a CF
>> composite plate or tube is like a glass plate or tube, or that a CF
>> bike is like one made of glass. The comparison is to other materials
>> commonly used for bicycle/component manufacture -- steel, aluminum
>> and titanium. In comparison to those materials, CF is indeed brittle,
>> and has much lower impact resistance.
>>
>> <http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites>
>>
>>
>> The main disadvantage of carbon (graphite) fibers is catastrophic mode
>> of failure (carbon fibers are brittle).
>>
>> Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
>> following properties:
>>
>> *
>> Light weight;
>> *
>> High strength-to-weight ratio;
>> *
>> Very High modulus elasticity-to-weight ratio;
>> *
>> High Fatigue strength;
>> *
>> Good corrosion resistance;
>> *
>> Very low coefficient of thermal expansion;
>> *
>> Low impact resistance;
>> *
>> High electric conductivity;
>> *
>> High cost.
>>
>> <http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566>
>>
>>
>> "The studies with the carbon fiber composites reveal the brittle
>> nature of this material, particularly when compared to the glass fiber
>> composites."
>>
>> <http://en.wikipedia.org/wiki/Tensile_strength>
>>
>> "Brittle materials such as concrete and carbon fiber do not have a
>> yield point, and do not strain-harden which means that the ultimate
>> strength and breaking strength are the same. A most unusual
>> stress-strain curve is shown in the figure below. Typical brittle
>> materials do not show any plastic deformation but fail while the
>> deformation is elastic. One of the characteristics of a brittle
>> failure is that the two broken parts can be reassembled to produce the
>> same shape as the original component. A typical stress strain curve
>> for a brittle material will be linear."
>>
>> <http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html>
>>
>> "The outstanding design properties of carbon fiber/resin matrix
>> composites are their high strength-to-weight and stiffness-to-weight
>> ratios. With proper selection and placement of fibers, the composites
>> can be stronger and stiffer than equivalent thickness steel parts and
>> weigh 40 to 70% less. Fatigue resistance of continuous-fiber
>> composites is excellent, and chemical resistance is better than that
>> of glass-reinforced systems, particularly in alkaline environments.
>> Like most rigid materials, however, carbon-fiber composites are
>> relatively brittle. The composites have no yield behavior, and
>> resistance to impact is low."
>>
>> A rather good primer:
>> <http://www.advancedcomposites.com/technology.htm>
>>
>> Says what I have been saying:
>>
>> "The primary advantage of composite materials over more conventional
>> metallic or polymeric materials is their anisotropic mechanical
>> response. This resulting directionality is carefully used to advantage."
>>
>> And:
>> "Figures 11. and 12. Illustrate how dramatically the properties of
>> plus/minus angle laminates change versus angle."
>>
>> Also an overview of failure mechanisms.
>
>
> ah, the peter cole approach: "keep trying to baffle them with bull".
I've provided citations. Your turn.
>
> since this is the fundamental intellectual hurdle you can't seem to
> overcome, let's cut to the point - you go ahead and define "brittle".
It was defined above. Apparently you don't even read my posts.
> and /please/ try not to deceive by citing anisotropy as evidence. thank
> you.
It makes no sense to ignore anisotropy since that's a primary
characteristic.
|
| | | | | | | | | | |
Date: 28 Aug 2007 05:51:24
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>>>
>>>>>> that's such a crock. you don't know basic deformation theory and
>>>>>> yet base claims of denial on this fundamental ignorance. and when
>>>>>> confronted with fact, you deny. but all the while, you play to
>>>>>> the peanut gallery like you're the victim with this classic
>>>>>> passive-aggressive bullshit. you're a complete prick.
>>>>>
>>>>> Let's drop all the infantile name calling and cut to the chase,
>>>>> shall we? Your claim that CF composite is not brittle is contrary
>>>>> to every source I have seen, to say that yours is a minority
>>>>> viewpoint would be to give it too much credit. You're dead wrong
>>>>> and only resort to this nonsense to try to bluff your way out.
>>>>> Nobody's buying it.
>>>>
>>>> what's your source? conan o'brien's mom?
>>>>
>>>> carbon composites are not brittle like glass is brittle, which is
>>>> what you seem to want us to believe. "brittle" is defined by energy
>>>> absorption on fracture and the deformation mechanism.
>>>
>>> Oh, please -- now the "ad absurdum" approach. No one is claiming a CF
>>> composite plate or tube is like a glass plate or tube, or that a CF
>>> bike is like one made of glass. The comparison is to other materials
>>> commonly used for bicycle/component manufacture -- steel, aluminum
>>> and titanium. In comparison to those materials, CF is indeed brittle,
>>> and has much lower impact resistance.
>>>
>>> <http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites>
>>>
>>>
>>> The main disadvantage of carbon (graphite) fibers is catastrophic
>>> mode of failure (carbon fibers are brittle).
>>>
>>> Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
>>> following properties:
>>>
>>> *
>>> Light weight;
>>> *
>>> High strength-to-weight ratio;
>>> *
>>> Very High modulus elasticity-to-weight ratio;
>>> *
>>> High Fatigue strength;
>>> *
>>> Good corrosion resistance;
>>> *
>>> Very low coefficient of thermal expansion;
>>> *
>>> Low impact resistance;
>>> *
>>> High electric conductivity;
>>> *
>>> High cost.
>>>
>>> <http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566>
>>>
>>>
>>> "The studies with the carbon fiber composites reveal the brittle
>>> nature of this material, particularly when compared to the glass
>>> fiber composites."
>>>
>>> <http://en.wikipedia.org/wiki/Tensile_strength>
>>>
>>> "Brittle materials such as concrete and carbon fiber do not have a
>>> yield point, and do not strain-harden which means that the ultimate
>>> strength and breaking strength are the same. A most unusual
>>> stress-strain curve is shown in the figure below. Typical brittle
>>> materials do not show any plastic deformation but fail while the
>>> deformation is elastic. One of the characteristics of a brittle
>>> failure is that the two broken parts can be reassembled to produce
>>> the same shape as the original component. A typical stress strain
>>> curve for a brittle material will be linear."
>>>
>>> <http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html>
>>>
>>> "The outstanding design properties of carbon fiber/resin matrix
>>> composites are their high strength-to-weight and stiffness-to-weight
>>> ratios. With proper selection and placement of fibers, the composites
>>> can be stronger and stiffer than equivalent thickness steel parts and
>>> weigh 40 to 70% less. Fatigue resistance of continuous-fiber
>>> composites is excellent, and chemical resistance is better than that
>>> of glass-reinforced systems, particularly in alkaline environments.
>>> Like most rigid materials, however, carbon-fiber composites are
>>> relatively brittle. The composites have no yield behavior, and
>>> resistance to impact is low."
>>>
>>> A rather good primer:
>>> <http://www.advancedcomposites.com/technology.htm>
>>>
>>> Says what I have been saying:
>>>
>>> "The primary advantage of composite materials over more conventional
>>> metallic or polymeric materials is their anisotropic mechanical
>>> response. This resulting directionality is carefully used to advantage."
>>>
>>> And:
>>> "Figures 11. and 12. Illustrate how dramatically the properties of
>>> plus/minus angle laminates change versus angle."
>>>
>>> Also an overview of failure mechanisms.
>>
>>
>> ah, the peter cole approach: "keep trying to baffle them with bull".
>
> I've provided citations. Your turn.
>
>
>>
>> since this is the fundamental intellectual hurdle you can't seem to
>> overcome, let's cut to the point - you go ahead and define "brittle".
>
> It was defined above. Apparently you don't even read my posts.
yes i did, and there is no definition of brittle, only use of the term,
in context no less. but you won't define the term because it won't suit
your purpose of deceit.
>
>
>> and /please/ try not to deceive by citing anisotropy as evidence.
>> thank you.
>
> It makes no sense to ignore anisotropy since that's a primary
> characteristic.
but you're citing anisotropy as if it's somehow "evidence" of
brittleness. it's not.
|
| | | | | | | | | | | |
Date: 29 Aug 2007 08:51:03
From: Peter Cole
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>>>> Peter Cole wrote:
>>>>>> jim beam wrote:
>>>>>>
>>>>>>> that's such a crock. you don't know basic deformation theory and
>>>>>>> yet base claims of denial on this fundamental ignorance. and
>>>>>>> when confronted with fact, you deny. but all the while, you play
>>>>>>> to the peanut gallery like you're the victim with this classic
>>>>>>> passive-aggressive bullshit. you're a complete prick.
>>>>>>
>>>>>> Let's drop all the infantile name calling and cut to the chase,
>>>>>> shall we? Your claim that CF composite is not brittle is contrary
>>>>>> to every source I have seen, to say that yours is a minority
>>>>>> viewpoint would be to give it too much credit. You're dead wrong
>>>>>> and only resort to this nonsense to try to bluff your way out.
>>>>>> Nobody's buying it.
>>>>>
>>>>> what's your source? conan o'brien's mom?
>>>>>
>>>>> carbon composites are not brittle like glass is brittle, which is
>>>>> what you seem to want us to believe. "brittle" is defined by
>>>>> energy absorption on fracture and the deformation mechanism.
>>>>
>>>> Oh, please -- now the "ad absurdum" approach. No one is claiming a
>>>> CF composite plate or tube is like a glass plate or tube, or that a
>>>> CF bike is like one made of glass. The comparison is to other
>>>> materials commonly used for bicycle/component manufacture -- steel,
>>>> aluminum and titanium. In comparison to those materials, CF is
>>>> indeed brittle, and has much lower impact resistance.
>>>>
>>>> <http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites>
>>>>
>>>>
>>>> The main disadvantage of carbon (graphite) fibers is catastrophic
>>>> mode of failure (carbon fibers are brittle).
>>>>
>>>> Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
>>>> following properties:
>>>>
>>>> *
>>>> Light weight;
>>>> *
>>>> High strength-to-weight ratio;
>>>> *
>>>> Very High modulus elasticity-to-weight ratio;
>>>> *
>>>> High Fatigue strength;
>>>> *
>>>> Good corrosion resistance;
>>>> *
>>>> Very low coefficient of thermal expansion;
>>>> *
>>>> Low impact resistance;
>>>> *
>>>> High electric conductivity;
>>>> *
>>>> High cost.
>>>>
>>>> <http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566>
>>>>
>>>>
>>>> "The studies with the carbon fiber composites reveal the brittle
>>>> nature of this material, particularly when compared to the glass
>>>> fiber composites."
>>>>
>>>> <http://en.wikipedia.org/wiki/Tensile_strength>
>>>>
>>>> "Brittle materials such as concrete and carbon fiber do not have a
>>>> yield point, and do not strain-harden which means that the ultimate
>>>> strength and breaking strength are the same. A most unusual
>>>> stress-strain curve is shown in the figure below. Typical brittle
>>>> materials do not show any plastic deformation but fail while the
>>>> deformation is elastic. One of the characteristics of a brittle
>>>> failure is that the two broken parts can be reassembled to produce
>>>> the same shape as the original component. A typical stress strain
>>>> curve for a brittle material will be linear."
>>>>
>>>> <http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html>
>>>>
>>>> "The outstanding design properties of carbon fiber/resin matrix
>>>> composites are their high strength-to-weight and stiffness-to-weight
>>>> ratios. With proper selection and placement of fibers, the
>>>> composites can be stronger and stiffer than equivalent thickness
>>>> steel parts and weigh 40 to 70% less. Fatigue resistance of
>>>> continuous-fiber composites is excellent, and chemical resistance is
>>>> better than that of glass-reinforced systems, particularly in
>>>> alkaline environments. Like most rigid materials, however,
>>>> carbon-fiber composites are relatively brittle. The composites have
>>>> no yield behavior, and resistance to impact is low."
>>>>
>>>> A rather good primer:
>>>> <http://www.advancedcomposites.com/technology.htm>
>>>>
>>>> Says what I have been saying:
>>>>
>>>> "The primary advantage of composite materials over more conventional
>>>> metallic or polymeric materials is their anisotropic mechanical
>>>> response. This resulting directionality is carefully used to
>>>> advantage."
>>>>
>>>> And:
>>>> "Figures 11. and 12. Illustrate how dramatically the properties of
>>>> plus/minus angle laminates change versus angle."
>>>>
>>>> Also an overview of failure mechanisms.
>>>
>>>
>>> ah, the peter cole approach: "keep trying to baffle them with bull".
>>
>> I've provided citations. Your turn.
>>
>>
>>>
>>> since this is the fundamental intellectual hurdle you can't seem to
>>> overcome, let's cut to the point - you go ahead and define "brittle".
>>
>> It was defined above. Apparently you don't even read my posts.
>
> yes i did, and there is no definition of brittle, only use of the term,
> in context no less. but you won't define the term because it won't suit
> your purpose of deceit.
What would you like to add to the description in the Wikipedia cite?
You have repeatedly insinuated that high strength materials cannot be
brittle. That is wrong. Stop tap dancing and state your point -- if you can.
>
>
>>
>>
>>> and /please/ try not to deceive by citing anisotropy as evidence.
>>> thank you.
>>
>> It makes no sense to ignore anisotropy since that's a primary
>> characteristic.
>
> but you're citing anisotropy as if it's somehow "evidence" of
> brittleness. it's not.
I am not doing that. You seem to not get the reality that an anisotropic
material can't be described for qualities like brittleness without
qualifying direction. Uniaxial CFRP is brittle in the fiber axis but not
orthogonal. In one mode you see the characteristics of the fiber
(brittle) in the other, the matrix (not brittle). To get strong/stiff
composite parts you have to construct in such a way that the fiber
characteristics dominate. By necessity that gives you parts that are as
brittle as the underlying fiber. Ergo, low impact tolerance.
If what you claim is true, you should be able to provide citations. Your
failure to do so speaks volumes, despite your evasions.
|
| | | | | | | | | | | | |
Date: 03 Sep 2007 06:17:58
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>>>> Peter Cole wrote:
>>>>>>> jim beam wrote:
>>>>>>>
>>>>>>>> that's such a crock. you don't know basic deformation theory
>>>>>>>> and yet base claims of denial on this fundamental ignorance.
>>>>>>>> and when confronted with fact, you deny. but all the while, you
>>>>>>>> play to the peanut gallery like you're the victim with this
>>>>>>>> classic passive-aggressive bullshit. you're a complete prick.
>>>>>>>
>>>>>>> Let's drop all the infantile name calling and cut to the chase,
>>>>>>> shall we? Your claim that CF composite is not brittle is contrary
>>>>>>> to every source I have seen, to say that yours is a minority
>>>>>>> viewpoint would be to give it too much credit. You're dead wrong
>>>>>>> and only resort to this nonsense to try to bluff your way out.
>>>>>>> Nobody's buying it.
>>>>>>
>>>>>> what's your source? conan o'brien's mom?
>>>>>>
>>>>>> carbon composites are not brittle like glass is brittle, which is
>>>>>> what you seem to want us to believe. "brittle" is defined by
>>>>>> energy absorption on fracture and the deformation mechanism.
>>>>>
>>>>> Oh, please -- now the "ad absurdum" approach. No one is claiming a
>>>>> CF composite plate or tube is like a glass plate or tube, or that a
>>>>> CF bike is like one made of glass. The comparison is to other
>>>>> materials commonly used for bicycle/component manufacture --
>>>>> steel, aluminum and titanium. In comparison to those materials, CF
>>>>> is indeed brittle, and has much lower impact resistance.
>>>>>
>>>>> <http://www.substech.com/dokuwiki/doku.php?id=carbon_fiber_reinforced_polymer_composites>
>>>>>
>>>>>
>>>>> The main disadvantage of carbon (graphite) fibers is catastrophic
>>>>> mode of failure (carbon fibers are brittle).
>>>>>
>>>>> Carbon Fiber Reinforced Polymers (CFRP) are characterized by the
>>>>> following properties:
>>>>>
>>>>> *
>>>>> Light weight;
>>>>> *
>>>>> High strength-to-weight ratio;
>>>>> *
>>>>> Very High modulus elasticity-to-weight ratio;
>>>>> *
>>>>> High Fatigue strength;
>>>>> *
>>>>> Good corrosion resistance;
>>>>> *
>>>>> Very low coefficient of thermal expansion;
>>>>> *
>>>>> Low impact resistance;
>>>>> *
>>>>> High electric conductivity;
>>>>> *
>>>>> High cost.
>>>>>
>>>>> <http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA036566>
>>>>>
>>>>>
>>>>> "The studies with the carbon fiber composites reveal the brittle
>>>>> nature of this material, particularly when compared to the glass
>>>>> fiber composites."
>>>>>
>>>>> <http://en.wikipedia.org/wiki/Tensile_strength>
>>>>>
>>>>> "Brittle materials such as concrete and carbon fiber do not have a
>>>>> yield point, and do not strain-harden which means that the ultimate
>>>>> strength and breaking strength are the same. A most unusual
>>>>> stress-strain curve is shown in the figure below. Typical brittle
>>>>> materials do not show any plastic deformation but fail while the
>>>>> deformation is elastic. One of the characteristics of a brittle
>>>>> failure is that the two broken parts can be reassembled to produce
>>>>> the same shape as the original component. A typical stress strain
>>>>> curve for a brittle material will be linear."
>>>>>
>>>>> <http://machinedesign.com/BDE/materials/bdemat3/bdemat3_2.html>
>>>>>
>>>>> "The outstanding design properties of carbon fiber/resin matrix
>>>>> composites are their high strength-to-weight and
>>>>> stiffness-to-weight ratios. With proper selection and placement of
>>>>> fibers, the composites can be stronger and stiffer than equivalent
>>>>> thickness steel parts and weigh 40 to 70% less. Fatigue resistance
>>>>> of continuous-fiber composites is excellent, and chemical
>>>>> resistance is better than that of glass-reinforced systems,
>>>>> particularly in alkaline environments. Like most rigid materials,
>>>>> however, carbon-fiber composites are relatively brittle. The
>>>>> composites have no yield behavior, and resistance to impact is low."
>>>>>
>>>>> A rather good primer:
>>>>> <http://www.advancedcomposites.com/technology.htm>
>>>>>
>>>>> Says what I have been saying:
>>>>>
>>>>> "The primary advantage of composite materials over more
>>>>> conventional metallic or polymeric materials is their anisotropic
>>>>> mechanical response. This resulting directionality is carefully
>>>>> used to advantage."
>>>>>
>>>>> And:
>>>>> "Figures 11. and 12. Illustrate how dramatically the properties of
>>>>> plus/minus angle laminates change versus angle."
>>>>>
>>>>> Also an overview of failure mechanisms.
>>>>
>>>>
>>>> ah, the peter cole approach: "keep trying to baffle them with bull".
>>>
>>> I've provided citations. Your turn.
>>>
>>>
>>>>
>>>> since this is the fundamental intellectual hurdle you can't seem to
>>>> overcome, let's cut to the point - you go ahead and define "brittle".
>>>
>>> It was defined above. Apparently you don't even read my posts.
>>
>> yes i did, and there is no definition of brittle, only use of the
>> term, in context no less. but you won't define the term because it
>> won't suit your purpose of deceit.
>
> What would you like to add to the description in the Wikipedia cite?
>
> You have repeatedly insinuated that high strength materials cannot be
> brittle. That is wrong. Stop tap dancing and state your point -- if you
> can.
>
>
>>
>>
>>>
>>>
>>>> and /please/ try not to deceive by citing anisotropy as evidence.
>>>> thank you.
>>>
>>> It makes no sense to ignore anisotropy since that's a primary
>>> characteristic.
>>
>> but you're citing anisotropy as if it's somehow "evidence" of
>> brittleness. it's not.
>
> I am not doing that. You seem to not get the reality that an anisotropic
> material can't be described for qualities like brittleness without
> qualifying direction. Uniaxial CFRP is brittle in the fiber axis but not
> orthogonal. In one mode you see the characteristics of the fiber
> (brittle) in the other, the matrix (not brittle). To get strong/stiff
> composite parts you have to construct in such a way that the fiber
> characteristics dominate. By necessity that gives you parts that are as
> brittle as the underlying fiber. Ergo, low impact tolerance.
>
> If what you claim is true, you should be able to provide citations. Your
> failure to do so speaks volumes, despite your evasions.
wow. you're still massively confused. but rather than pick through a
stale old thread, let's start again...
|
| | | | | | | | | | | | | |
Date: 03 Sep 2007 20:36:14
From: Jambo
Subject: Re: "CF Bike Shatters" - continued
|
"jim beam" <spamvortex@bad.example.net > wrote in message
news:-7SdnVsauPYalEHbnZ2dnUVZ_sPinZ2d@speakeasy.net...
> wow. you're still massively confused. but rather than pick through a
> stale old thread, let's start again...
You can start again as many times as you like, you're still going to be
wrong. Why not just take your own advice, learn from the data you've been
shown, and move on? You must think you have a reputation to save here on
rbt. Let me assure you that you don't.
|
| | | | | | | | | | | | | | |
Date: 03 Sep 2007 18:36:32
From: jim beam
Subject: Re: "CF Bike Shatters" - continued
|
Jambo wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:-7SdnVsauPYalEHbnZ2dnUVZ_sPinZ2d@speakeasy.net...
>> wow. you're still massively confused. but rather than pick through a
>> stale old thread, let's start again...
>
> You can start again as many times as you like, you're still going to be
> wrong.
really?
> Why not just take your own advice, learn from the data you've been
> shown, and move on?
so when are /you/ going to learn?
> You must think you have a reputation to save here on
> rbt. Let me assure you that you don't.
so the fuck what? i'm not selling anything so who the fuck cares?
but at the same time, /i'm/ not being a jackass by ridiculously ignoring
industry standard testing in aerospace, while trying to insist on
aerospace for bike apps as a way to try fudging the facts.
|
| | | | | | | |
Date: 26 Aug 2007 11:49:07
From: J. Clarke
Subject: Re: "CF Bike Shatters" - continued
|
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>
>>> that's such a crock. you don't know basic deformation theory and
>>> yet base claims of denial on this fundamental ignorance. and when
>>> confronted with fact, you deny. but all the while, you play to
>>> the
>>> peanut gallery like you're the victim with this classic
>>> passive-aggressive bullshit. you're a complete prick.
>>
>> Let's drop all the infantile name calling and cut to the chase,
>> shall
>> we? Your claim that CF composite is not brittle is contrary to
>> every
>> source I have seen, to say that yours is a minority viewpoint would
>> be to give it too much credit. You're dead wrong and only resort to
>> this nonsense to try to bluff your way out. Nobody's buying it.
>
> what's your source? conan o'brien's mom?
>
> carbon composites are not brittle like glass is brittle, which is
> what
> you seem to want us to believe. "brittle" is defined by energy
> absorption on fracture and the deformation mechanism.
You aren't by any chance the idiot who talked the management at
Rolls-Royce into betting the company on carbon fiber fan blades, are
you?
--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
|
| | | | | |
Date: 25 Aug 2007 19:18:46
From: Ted Bennett
Subject: Re: "CF Bike Shatters" - continued
|
In article <-fCdnQ091PzMSE3bnZ2dnUVZ_tKinZ2d@speakeasy.net >,
jim beam <spamvortex@bad.example.net > wrote:
> Peter Cole wrote:
> > jim beam wrote:
> >> Peter Cole wrote:
> >>> jim beam wrote:
> >>>> Peter Cole wrote:
> >>>>> jim beam wrote:
> >>>>>> the "CF Bike Shatters" thread is now too deep for me to follow on my
> >>>>>> limited screen real estate - i'm starting a new thread.
> >>>>>>
> >>>>>> peter cole wrote:
> >>>>>>> jim beam wrote:
> >>>>>>>> Peter Cole wrote:
> >>>>>>>
> >>>>>>>>> Find one to support your claim that carbon fibers aren't brittle
> >>>>>>>>> & I'll read along.
> >>>>>>>>
> >>>>>>>> learn about yield before you /dare/ to lecture on deformation,
> >>>>>>>> bullshitter.
> >>>>>>>
> >>>>>>> Oh please. Typical "jim beam" switcharoo. We're talking about
> >>>>>>> fracture (see thread title).
> >>>>>>
> >>>>>> you're confusing fracture of brittle materials with fracture of
> >>>>>> ductile materials -
> >>>>>
> >>>>> I'm not "confusing" them, I'm comparing them.
> >>>>
> >>>> but you are confusing them - you're not differentiating between
> >>>> ductile and brittle - and that's pretty damned fundamental.
> >>>
> >>>
> >>> You can keep saying that, but I'm not.
> >>
> >> "6061 elongation is 26%". that's plastic deformation.
> >> "carbon fiber elongation is 1.5%". that's elastic deformation.
> >>
> >> there's a fundamental difference an "engineer" should understand.
> >
> >
> > Yes, that's obvious. Who said it wasn't?
>
> anyone mistaking plastic elongation for plastic elongation /clearly/
> doesn't find the distinction "obvious".
>
>
> >
> > You don't have to put quotes around engineer.
>
> you do if it's a name someone calls themselves, but doesn't evidence
> qualification.
>
>
> >
> >
> >>
> >>
> >>>
> >>>>
> >>>>>
> >>>>>
> >>>>>>> Carbon fibers are brittle.
> >>>>>>
> >>>>>> in isolation, they are. so is any high strength material. but
> >>>>>> cfrp is
> >>>>>> not. what's why we use it!
> >>>>>
> >>>>> I don't know who "we" is.
> >>>>
> >>>> prick.
> >>>>
> >>>>>
> >>>>> You're absolutely wrong about CFRP. You can't discuss an inherently
> >>>>> anisotropic material without qualifying by fiber orientation
> >>>>> (pretty much my whole point).
> >>>>
> >>>> eh? /you/ are defeating your own argument!!! first you b.s. about
> >>>> "isotropic" cfrp, now you're admitting that it's inherently not!!!
> >>>
> >>> Nonsense, read it again.
> >>
> >> evasive b.s.
> >
> > You can't discuss CFRP without layup schedule. Uniaxial CFRP has
> > impressive numbers -- in one direction.
>
> "in one direction" indeed. so why bleat about isotropy as if it's a
> base property? because you're bullshitting and trying to muddy the
> water, that's why!
>
>
> >
> >
> >>>
> >>>>
> >>>>>
> >>>>> A unidirectional fiber composite will have characteristics very
> >>>>> much like those of the reinforcing fiber when loaded on-axis.
> >>>>> Off-axis, those properties change rapidly,
> >>>>
> >>>> they don't just "change rapidly", they're completely different.
> >>>> that's why it's anisotropic!!!
> >>>>
> >>>>> becoming essentially those of the matrix at 90 degrees.
> >>>>
> >>>> mince words whydontcha
> >>>
> >>> Nonsense, read it again.
> >>
> >> more evasive b.s.
> >
> > If you take the trouble to look at the stress-strain of uniaxial CFRP as
> > the load angle changes, all will become clear.
>
> says the guy that bullshits about elongation while getting confused
> between plastic and elastic deformation...
>
>
> >
> >
> >>
> >>>
> >>>>
> >>>>>
> >>>>>>
> >>>>>>> They elongate
> >>>>>>> only between 0.8 - 1.4% before fracture in tension. E-glass is >3x
> >>>>>>> that, 6061 is ~20x that.
> >>>>>>
> >>>>>> you're mixing apples with oranges. carbon fiber [and glass fiber]
> >>>>>> have
> >>>>>> no deformation mechanism, no dislocation function. so they have no
> >>>>>> ductility. so they are "brittle". again, this is not to be confused
> >>>>>> with the behavior of their composites.
> >>>>>
> >>>>> On-axis, the behavior of composite and fiber are very similar.
> >>>>
> >>>> but composites rarely if ever use solely uniaxial layup. you're
> >>>> trying to twist the facts again.
> >>>
> >>> I simply stated a fact.
> >>
> >> no, you twisted "facts" to state an untruth.
> >
> > Composite will be as brittle as it is strong. Try to understand that.
>
> !!! sure! there measured in the same units too aren't they!!!
>
>
> >
> >
> >>>
> >>>>>
> >>>>>
> >>>>>> for glass and carbon, their stress/strain graphs are much extended -
> >>>>>
> >>>>> Extended from what?
> >>>>
> >>>> compared to the ductile materials with which you're confused.
> >>>>
> >>>>>
> >>>>>> what would be the hooke's law region of a ductile material.
> >>>>>
> >>>>> I give up, what?
> >>>>
> >>>> that wasn't a question. i missed the word "from" - which you'd have
> >>>> spotted if you weren't so intent on being a prick.
> >>>
> >>> Your statement is still incoherent.
> >>
> >> eh? that you don't understand the difference between elastic and
> >> plastic deformation?
> >>
> >
> > I certainly do, it's not so very hard to grasp.
>
> so why the painful confusion between plastic and elastic? stupidity?
> or deliberate bullshit?
>
>
> >
> >
> >>>
> >>>
> >>>
> >>>>>
> >>>>>>
> >>>>>>> If you have a source (other than yourself)
> >>>>>>> that says otherwise, I'm all ears.
> >>>>>>
> >>>>>> go to a library!
> >>>>>> you can also look at this:
> >>>>>> http://www.flickr.com/photos/38636024@N00/1208725721/
> >>>>>> the "x" points are the "failure" points for all the materials
> >>>>>> since onset of yield is failure.
> >>>>>
> >>>>> Citing yourself again? Why am I not surprised. You're never going
> >>>>> to learn anything that way.
> >>>>
> >>>> prick. /you/ won't admit that you don't understand the difference
> >>>> between ductile and brittle. if you won't open a book, then i have
> >>>> to show you.
> >>>
> >>> Your diagram has no useful information.
> >>
> >> eh? it illustrates different deformation for different materials -
> >> elastic and plastic. something you don't seem to understand.
> >
> > It's not to scale, it attempts to depict fiber rather than composite. It
> > still doesn't explain why you disagree with the rest of the world about
> > CF composite being brittle.
>
> 1. what part of the label stating "NOT TO SCALE" is confusing to you???
> 2. composites have properties intermediate between the fiber and the
> matrix, depending on composition.
> 3. bullshit statements that "carbon is brittle" is as misleading as it
> is wrong.
>
> >
> >
> >>
> >>
> >>>
> >>>>>>> If you take the often cited 6x ultimate yield strength of CF, derate
> >>>>>>> it by the 4 plies (minimum, 0, 90 +-45) you need for isotropy, plus
> >>>>>>> the ratio of fiber to epoxy, you come out with nothing special wrt
> >>>>>>> overall strength.
> >>>>>>
> >>>>>> eh? why do you need isotropy??? oh, you're trying to force an
> >>>>>> argument where none exists. my bad.
> >>>>>
> >>>>> No, I'm trying to compare "apples to apples" -- material
> >>>>> suitability for isotropic loading.
> >>>>
> >>>> aha! more fundamental misunderstanding - there's no such thing as
> >>>> isotropic loading. that's why we have poisson's ratio.
> >>>
> >>> Now who's mincing words?
> >>
> >> eh? you want me to be more direct? ok. you're an "engineer" that
> >> doesn't know the fundamentals of deformation on loading. that's
> >> pretty fucking weak.
> >>
> >> that unmincing enough for you?
> >
> > That's lovely (in sentiment) but unfortunately still incoherent.
>
> /your/ confusion between elastic and plastic is incoherent buddy.
>
>
> >
> >
> >>>
> >>>
> >>>>
> >>>>>
> >>>>>
> >>>>>>> That's why there isn't much difference in CF vs Al
> >>>>>>> handlebars and seatposts (except price).
> >>>>>>
> >>>>>> incorrect. it's because it's relatively cheap fiber, relatively
> >>>>>> imprecise manufacturing and a generous safety margin.
> >>>>>
> >>>>> How do you know what the safety margin is?
> >>>>> How do you know what the fiber is?
> >>>>> How do you know what the process is?
> >>>>
> >>>> are you denying the facts?
> >>>
> >>> Show me a fact & I'll get back to you on that.
> >>
> >> denial. prick.
> >
> > I do hope you get help with your Tourette's, meanwhile, got any facts?
>
> fuck you, prick. you've already got facts of principle. what you're
> bleating about is numbers. but you're no stranger to deliberate
> muddying of the water are you.
>
>
> >
> >
> >>>>>
> >>>>> In the past, you've made the rather obvious point that it's silly
> >>>>> to talk about metals without knowing the specific alloy. Now,
> >>>>> you're making gross generalizations about a material which has much
> >>>>> greater parameterization.
> >>>>
> >>>> principle apply, big guy.
> >>>
> >>> That's informative!
> >>
> >> from someone that doesn't know basic engineering principles like the
> >> difference between elastic and plastic, that's a real dumb-ass statement.
> >
> >
> > OK, what "principle"?
>
> er, how about we start with "elastic is not plastic"?
>
>
> >
> >
> >>
> >>
> >>>
> >>>
> >>>
> >>>>> As far as I know, no component or frame manufacturer publishes
> >>>>> layup schedules.
> >>>>
> >>>> they don't quantify, but they do illustrate. you should look some
> >>>> time.
> >>>
> >>> I tried. Why don't you post some of the examples you've found?
> >>
> >> why do i have to do all the heavy lifting??? you're the prick
> >> contesting the issue.
> >
> > I didn't think you had any.
>
> bullshit.
>
>
> > Given that they're all proprietary,
>
> bullshit! spectacular avoidance!!!
>
>
> > that
> > would have been impressive. So just go on in through-your-hat mode (I'm
> > much too polite to use the obvious term).
>
> oh, please, let me - you're a prick, "mr. engineer".
>
>
> >
> >
> >>>>
> >>>>> If you have any, please share. You claimed that a "visit to a bike
> >>>>> shop" would allow one to learn this.
> >>>>
> >>>> campy carbon cranks. you can see the exterior layup pattern -
> >>>> inconvenient for you to admit though this may be.
> >>>>
> >>>>
> >>>>> I fail to see how visual inspection of a composite part would
> >>>>> reveal the layup schedule.
> >>>>
> >>>> er, because you can see the exterior through the clearcoat? but you
> >>>> wan tto talk substrate? well, you'll have to look online, won't you.
> >
> > Show me a link, & I'll be right over.
>
> no, you get your deceitful ass on over to a shop.
>
>
> >
> >
> >
> >>>>
> >>>>
> >>>>> At best, you could perhaps get a little information on the
> >>>>> outermost ply, often, not even that.
> >>>>
> >>>> bingo.
> >>>
> >>> That's your idea of a layup schedule?
> >>
> >> no. but you're my idea of an evasive prick.
> >
> > What about layup schedule (I already know your opinion of me)?
>
> see above.
>
>
>
> >
> >
> >
> >>
> >>>
> >>>
> >>>>>>> It's only when you exploit
> >>>>>>> anisotropy that CF makes sense, but then you're stuck with lack of
> >>>>>>> impact resistance and brittle failure as a trade off.
> >>>>>>
> >>>>>> but you have that kind of trade off with /any/ high strength
> >>>>>> material, even steel. the higher the strength, the more brittle.
> >>>>>
> >>>>> You're missing the point about anisotropy.
> >>>>
> >>>> no i'm not. and that's a spectacular statement from a guy that
> >>>> doesn't understand the difference between ductile elongation and
> >>>> brittle fracture.
> >>>
> >>> Repeating that doesn't make it true.
> >>
> >> no, being true makes it true. repeating denial can't make it untrue.
> >>
> >>
> >>> You, on the other hand, seem to be the only one on the planet who
> >>> doesn't see that CFRP has low impact resistance.
> >>
> >> bullshit.
> >>
> >> 1. who the fuck wants their frame to be resistant to artillery fire.
> >> 2. "impact resistance" is a function of the fiber itself, the layup,
> >> the fiber length, density, orientation and matrix - among other
> >> things. "CFRP has low impact resistance" is such a BULLSHIT dumb-ass
> >> statement, it beggars belief.
> >
> > Then why does everyone believe it but you?
>
> not everyone knows or cares. but that's why you muddy the water - so
> you can keep on bullshitting.
>
>
> >
> >
> >
> >>>
> >>>>>>> CF is great for
> >>>>>>> some apps, marginal for others and crappy for the rest. It's an
> >>>>>>> engineering thing.
> >>>>>>
> >>>>>> wow. condescension, massive over-generalization and naivety all
> >>>>>> in one.
> >>>>>
> >>>>> No, just engineering basics. With CF bars and posts, you get (more
> >>>>> expensive) parts with similar weights. You also get susceptibility
> >>>>> to damage from clamping pressure and/or impact. Crappy (yet
> >>>>> popular) applications.
> >>>>
> >>>> so when planes have warning labels on them telling crew not to walk
> >>>> on wings, that can be ignored? bullshit. carbon componentry has
> >>>> labels saying "do not clamp", "do not exceed...", etc., that can be
> >>>> ignored? bullshit.
> >>>
> >>> Who said anything about ignoring labels? I was talking about the need
> >>> for labels.
> >>
> >> so what would your labels say then? "er, this may be elastic or it
> >> may be plastic - we really don't know"?
> >
> > That does not even make a shred of sense.
>
> not knowing the distinction between the two deformation regimes you
> mean? agreed - makes ZERO sense for anyone purporting to be an engineer.
>
>
> >
> >>>
> >>>> twist all you want - you're still missing the basics.
> >>>
> >>> If you say so,
> >>
> >> damned right i say so!
> >>
> >> > but do try to scrape up a fact or two & perhaps we can go
> >>> from there.
> >>
> >> i have. but you seem too intent on being a persistently ignorant
> >> prick to absorb anything.
> >
> > I have yet to see a fact, only "jim beam"-ish self-cites. Perhaps
> > they're the same in your world, but not in the much bigger world the
> > rest of us live in.
>
> that's such a crock. you don't know basic deformation theory and yet
> base claims of denial on this fundamental ignorance. and when
> confronted with fact, you deny. but all the while, you play to the
> peanut gallery like you're the victim with this classic
> passive-aggressive bullshit. you're a complete prick.
Is that you, Ed Dolan?
--
Ted Bennett
|
| | | | | | |
Date: 26 Aug 2007 00:25:51
From: Tim McNamara
Subject: Re: "CF Bike Shatters" - continued
|
In article
<tedbennett-8A2AFE.19184625082007@earthlink.vsrv-sjc.supernews.net >,
Ted Bennett <tedbennett@earthlink.net > wrote:
> In article <-fCdnQ091PzMSE3bnZ2dnUVZ_tKinZ2d@speakeasy.net>,
> jim beam <spamvortex@bad.example.net> wrote:
>
> > Peter Cole wrote:
> > > jim beam wrote:
> > >> Peter Cole wrote: "6061 elongation is 26%". that's plastic
> > >> deformation. "carbon fiber elongation is 1.5%". that's elastic
> > >> deformation.
> > >>
> > >> there's a fundamental difference an "engineer" should
> > >> understand.
> > >
> > > Yes, that's obvious. Who said it wasn't?
> >
> > anyone mistaking plastic elongation for plastic elongation
> > /clearly/ doesn't find the distinction "obvious".
> >
> > > You don't have to put quotes around engineer.
> >
> > you do if it's a name someone calls themselves, but doesn't
> > evidence qualification.
OMG that is *so* f'in funny! Thanks, Ted, I wouldn't have seen this
without your help!
|
| | | | | | | |
Date: 26 Aug 2007 12:56:48
From: Ted Bennett
Subject: Re: "CF Bike Shatters" - continued
|
In article <timmcn-1F9FF8.00255126082007@news.iphouse.com >,
Tim McNamara <timmcn@bitstream.net > wrote:
> In article
> <tedbennett-8A2AFE.19184625082007@earthlink.vsrv-sjc.supernews.net>,
> Ted Bennett <tedbennett@earthlink.net> wrote:
>
> > In article <-fCdnQ091PzMSE3bnZ2dnUVZ_tKinZ2d@speakeasy.net>,
> > jim beam <spamvortex@bad.example.net> wrote:
> >
> > > Peter Cole wrote:
> > > > jim beam wrote:
> > > >> Peter Cole wrote: "6061 elongation is 26%". that's plastic
> > > >> deformation. "carbon fiber elongation is 1.5%". that's elastic
> > > >> deformation.
> > > >>
> > > >> there's a fundamental difference an "engineer" should
> > > >> understand.
> > > >
> > > > Yes, that's obvious. Who said it wasn't?
> > >
> > > anyone mistaking plastic elongation for plastic elongation
> > > /clearly/ doesn't find the distinction "obvious".
> > >
> > > > You don't have to put quotes around engineer.
> > >
> > > you do if it's a name someone calls themselves, but doesn't
> > > evidence qualification.
>
> OMG that is *so* f'in funny! Thanks, Ted, I wouldn't have seen this
> without your help!
I did not write anything you quoted.
Ted Bennett
--
Ted Bennett
|
| | | | | | | | |
Date: 26 Aug 2007 16:21:24
From: Tim McNamara
Subject: Re: "CF Bike Shatters" - continued
|
In article
<tedbennett-17FA37.12564826082007@earthlink.vsrv-sjc.supernews.net >,
Ted Bennett <tedbennett@earthlink.net > wrote:
> In article <timmcn-1F9FF8.00255126082007@news.iphouse.com>,
> Tim McNamara <timmcn@bitstream.net> wrote:
>
> > In article
> > <tedbennett-8A2AFE.19184625082007@earthlink.vsrv-sjc.supernews.net>,
> > Ted Bennett <tedbennett@earthlink.net> wrote:
> >
> > > In article <-fCdnQ091PzMSE3bnZ2dnUVZ_tKinZ2d@speakeasy.net>,
> > > jim beam <spamvortex@bad.example.net> wrote:
> > >
> > > > Peter Cole wrote:
> > > > > jim beam wrote:
> > > > >> Peter Cole wrote: "6061 elongation is 26%". that's plastic
> > > > >> deformation. "carbon fiber elongation is 1.5%". that's elastic
> > > > >> deformation.
> > > > >>
> > > > >> there's a fundamental difference an "engineer" should
> > > > >> understand.
> > > > >
> > > > > Yes, that's obvious. Who said it wasn't?
> > > >
> > > > anyone mistaking plastic elongation for plastic elongation
> > > > /clearly/ doesn't find the distinction "obvious".
> > > >
> > > > > You don't have to put quotes around engineer.
> > > >
> > > > you do if it's a name someone calls themselves, but doesn't
> > > > evidence qualification.
> >
> > OMG that is *so* f'in funny! Thanks, Ted, I wouldn't have seen this
> > without your help!
>
> I did not write anything you quoted.
True, I trimmed most of the post. It was just by way of thanking you
because jim beam lives in my killfile. I don't get to see such pearls
as this unless someone quotes it. This one was priceless!
|
|
