ASR and Comptech brace, which is stronger? FEA results inside!
10-13-2005, 12:48 PM
#26
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Re: (Eyal 951)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Eyal 951 »</TD></TR><TR><TD CLASS="quote">well, I've heard of people saying that they can flex the comptech brace by hand. The i beam portion my be strong, but its ony as strong as its weakes point which is the sides, that are thin, i beam less, and flexable.
I can't flex the asr brace by hand in any direction.
</TD></TR></TABLE>
Interesting... My new Comptech should be sitting on my front porch when I get home. (If not, I am going to hunt down the UPS man and kill him dead.) I'll see if I can bend it by hand and report back.
I can't flex the asr brace by hand in any direction.
</TD></TR></TABLE>
Interesting... My new Comptech should be sitting on my front porch when I get home. (If not, I am going to hunt down the UPS man and kill him dead.) I'll see if I can bend it by hand and report back.
10-13-2005, 02:50 PM
#28
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Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">
4.) Also they also just mention the stress and how low it is. They totally forget to mention the fact that it should be a weight concern as well for that kind of part. I don’t find it useful that they say that basically the part is less stressed, and therefore, it is better. I can beef up the part to hell, replace the material with stainless steel or titanium and have better stress results. But a ratio of max stress to weight will be VERY helpful for me.
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We are not talking about 50lbs here, this is 6061, not a super heavy metal. If weight is that big of a factor then go have your very own piece custom designed. Or get on a diet and start running.
You have to think about weight vs. strength. I think most people are willing to give up a few pounds to have a stronger car.
~Eric
PS just for reference here is a link for the 6061 T6 specs.
http://www.matweb.com/search/S...061T6
4.) Also they also just mention the stress and how low it is. They totally forget to mention the fact that it should be a weight concern as well for that kind of part. I don’t find it useful that they say that basically the part is less stressed, and therefore, it is better. I can beef up the part to hell, replace the material with stainless steel or titanium and have better stress results. But a ratio of max stress to weight will be VERY helpful for me.
</TD></TR></TABLE>
We are not talking about 50lbs here, this is 6061, not a super heavy metal. If weight is that big of a factor then go have your very own piece custom designed. Or get on a diet and start running.
You have to think about weight vs. strength. I think most people are willing to give up a few pounds to have a stronger car.
~Eric
PS just for reference here is a link for the 6061 T6 specs.
http://www.matweb.com/search/S...061T6
10-13-2005, 03:13 PM
#29
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Re: (SwedBoy2999)
honestly, i dont even know what the debate is really about. i just saw these "stress analysis" pics and it made me turn my head trying to figure out what the heck it was trying to accomplish. so i asked my friend to read the plots and comment. basically, whatever the plots are trying to show, the analysis is crap, and proves nothing. that even as a "qualitative" analysis, its bunk and you cannot draw any conclusion, like the author tried to make.
so good try, but try again...
so good try, but try again...
10-13-2005, 03:16 PM
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Re: (Eyal 951)
I have the Comptech strut bar right here, brand new, right out of the box. I can actually bend it slightly with my hands. But, it takes a hell of a lot to do so. Also, for me to noticeably bend it, I am bending it in ways that I seriously doubt it will bend when installed on the car. To really bend it noticeably, I have to grab it by the "ears" (point where the sway bar bracket mounts) and try to twist it. I may be wrong but I just don't see this thing having to endure much twisting force. I would expect that it will be subject to more up-and-down and side-to-side forces.
Regradless, I am impressed with it and I feel that it will do an outstanding job. Workmanship is very nice as well.
Regradless, I am impressed with it and I feel that it will do an outstanding job. Workmanship is very nice as well.
10-13-2005, 04:28 PM
#31
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Re: (GChambers)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GChambers »</TD></TR><TR><TD CLASS="quote"> neither is going to break under anything but the most extreme circumstances. Am I also correct about this?</TD></TR></TABLE>
"most" is easily accomplished with a 26mm mugen rear sway.
"most" is easily accomplished with a 26mm mugen rear sway.
10-13-2005, 08:18 PM
#32
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Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">honestly, i dont even know what the debate is really about. i just saw these "stress analysis" pics and it made me turn my head trying to figure out what the heck it was trying to accomplish. so i asked my friend to read the plots and comment. basically, whatever the plots are trying to show, the analysis is crap, and proves nothing. that even as a "qualitative" analysis, its bunk and you cannot draw any conclusion, like the author tried to make.
so good try, but try again...</TD></TR></TABLE>
Didn't you read the first post??? The debate started with someone claiming that the I-beam design (as in the Comptech) is superior than the ASR thicker plate design. This analysis proves that the I-beam design is NOT necessarily superior. If you think the analysis is crap and proved nothing, why don't you try doing the analysis? Prove to us that you know what you're talking about.
so good try, but try again...</TD></TR></TABLE>
Didn't you read the first post??? The debate started with someone claiming that the I-beam design (as in the Comptech) is superior than the ASR thicker plate design. This analysis proves that the I-beam design is NOT necessarily superior. If you think the analysis is crap and proved nothing, why don't you try doing the analysis? Prove to us that you know what you're talking about.
10-13-2005, 08:35 PM
#33
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Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">honestly, i dont even know what the debate is really about. i just saw these "stress analysis" pics and it made me turn my head trying to figure out what the heck it was trying to accomplish. so i asked my friend to read the plots and comment. basically, whatever the plots are trying to show, the analysis is crap, and proves nothing. that even as a "qualitative" analysis, its bunk and you cannot draw any conclusion, like the author tried to make.
so good try, but try again...</TD></TR></TABLE>
HAHA! Give me a break Tyson. Really, come on now.
As already stated, this was in response to a debate that has been long running. vwong was nice enough to do the analysis, and here are the results.
What really makes me laugh is that we went to the trouble to do the test to show what we thought was correct. We posted the results, and the only thing you can come up with is this?
"My buddy said that your analysis is crap, and he is really smart. So, this test means nothing.
Tell ya what, this test means a lot more than your comments. If you think it's crap, come up with your own test and show us so. Put your money where your mouth is!
Your comments go in line with what started this debate. Just opinion...
Not trying to attack you at all, just trying to state whats going on here!
so good try, but try again...</TD></TR></TABLE>
HAHA! Give me a break Tyson. Really, come on now.
As already stated, this was in response to a debate that has been long running. vwong was nice enough to do the analysis, and here are the results.
What really makes me laugh is that we went to the trouble to do the test to show what we thought was correct. We posted the results, and the only thing you can come up with is this?
"My buddy said that your analysis is crap, and he is really smart. So, this test means nothing.
Tell ya what, this test means a lot more than your comments. If you think it's crap, come up with your own test and show us so. Put your money where your mouth is!
Your comments go in line with what started this debate. Just opinion...
Not trying to attack you at all, just trying to state whats going on here!
10-13-2005, 11:03 PM
#34
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Re: (prkiller)
i dont claim to be the structural analyst. i work on high power laser systems (my background is opto-mechanics, i design "Laaaaasserrrsss"), essentially im just a catia v5 jock who gets paid to sit behind a computer and move pixels. i could model that up as nicely as you guys did (good job btw), but i wouldnt dare run the stress analysis program within catia without proper knowledge on how to do a stress analysis and share it with others and make it seem like i proved something. not without at least consulting someone else who has a clue. its pretty obvious you didnt. sorry, i dont mean to be mean and nasty, but really, you didnt. i understand you had limitations in your software, but that just means you shouldnt have even done the analysis. to make a conclusion on bunk analysis is just stupid, especially after youve been told. heck, even after a proper analysis, it may show that the comptech bar has its limitations below satisfactory, but your current analysis doesnt prove that.
you just need to constrain it properly and put real forces in the model. you analyzed nothing REAL. its not even a real material as pointed out. like i said, im a decent CAM jock, but im not a structural engineer. i know of those who are, and i asked more than one (theres many real structural engineers in my office bay) who laughed at that.
and no, i didnt read the post (was that a rhetorical question?) but i can tell you the good thing about an I-beam is that its got a good strength to weight ratio. but it certainly doesnt make it any stronger than an equivalently sized brick! (is that what you guys are trying to prove???) looks like ASR just machines a plate of aluminum and anodizes it purple. comptech looks like they actually put some engineering, or at least some thought, involved. both may accomplish the same goal, i wouldnt argue whats better in terms of achieving the same goal (since obviously a brick is going to stronger than a I beam), but the comptech one impresses me a heck of a lot more than the ASR. if weight means nothing, then just make something out of mild steel and drill a few holes. (it wouldnt be the first time ive seen that done for a rear subframe reinforcement on a crx)
here, give me .stp file of those two. ill run it on my catia box. we'll see how it goes. but if you guys are just trying to prove a plate of aluminum is stronger than an I-beam, you win. no need to do any analysis.
Modified by Tyson at 1:25 PM 2/23/2006
you just need to constrain it properly and put real forces in the model. you analyzed nothing REAL. its not even a real material as pointed out. like i said, im a decent CAM jock, but im not a structural engineer. i know of those who are, and i asked more than one (theres many real structural engineers in my office bay) who laughed at that.
and no, i didnt read the post (was that a rhetorical question?) but i can tell you the good thing about an I-beam is that its got a good strength to weight ratio. but it certainly doesnt make it any stronger than an equivalently sized brick! (is that what you guys are trying to prove???) looks like ASR just machines a plate of aluminum and anodizes it purple. comptech looks like they actually put some engineering, or at least some thought, involved. both may accomplish the same goal, i wouldnt argue whats better in terms of achieving the same goal (since obviously a brick is going to stronger than a I beam), but the comptech one impresses me a heck of a lot more than the ASR. if weight means nothing, then just make something out of mild steel and drill a few holes. (it wouldnt be the first time ive seen that done for a rear subframe reinforcement on a crx)
here, give me .stp file of those two. ill run it on my catia box. we'll see how it goes. but if you guys are just trying to prove a plate of aluminum is stronger than an I-beam, you win. no need to do any analysis.
Modified by Tyson at 1:25 PM 2/23/2006
10-13-2005, 11:05 PM
#35
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Re: (prkiller)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by prkiller »</TD></TR><TR><TD CLASS="quote">
"My buddy said that your analysis is crap, and he is really smart. So, this test means nothing."</TD></TR></TABLE>
so let me get this straight, "hey everyone, vwong made these awesome colorful pics with numbers and stuff that proves im right, (but nevermind that he didnt do a proper analysis nor had the software to do so which neither he nor i really understand)" thats better than asking several professional and educated engineers to scrutinize these results because im not qualified to do so myself?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by prkiller »</TD></TR><TR><TD CLASS="quote">
Not trying to attack you at all, just trying to state whats going on here!</TD></TR></TABLE>
nor am i trying to attack you. im just trying to let you know your analysis is totally wrong and thus any conclusions you made is not justified.
Modified by Tyson at 1:30 AM 10/14/2005
"My buddy said that your analysis is crap, and he is really smart. So, this test means nothing."</TD></TR></TABLE>
so let me get this straight, "hey everyone, vwong made these awesome colorful pics with numbers and stuff that proves im right, (but nevermind that he didnt do a proper analysis nor had the software to do so which neither he nor i really understand)" thats better than asking several professional and educated engineers to scrutinize these results because im not qualified to do so myself?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by prkiller »</TD></TR><TR><TD CLASS="quote">
Not trying to attack you at all, just trying to state whats going on here!</TD></TR></TABLE>
nor am i trying to attack you. im just trying to let you know your analysis is totally wrong and thus any conclusions you made is not justified.
Modified by Tyson at 1:30 AM 10/14/2005
10-14-2005, 06:43 AM
#37
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Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">i i work on high power laser systems </TD></TR></TABLE>
10-14-2005, 07:33 AM
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Re:
both Tyson and the Original poster have valid points... but Tyson did give us a pretty good summary with the brick/beam comparison... that's basically what this was - I won't argue with that.
vtecvoodoo: hahahahahah... nice pic
vtecvoodoo: hahahahahah... nice pic
10-14-2005, 09:11 AM
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Re: (vtecvoodoo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecvoodoo »</TD></TR><TR><TD CLASS="quote">
</TD></TR></TABLE>
REal Genius, man thats old.
</TD></TR></TABLE>REal Genius, man thats old.
10-14-2005, 09:13 AM
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Re: Re: (archmage)
Wow, I hate to rain on this parade here, but without a doubt this analysis is total crap. And no, this is not splitting hairs. When it comes to FEA analysis, the saying "garbage in, garbage out" is doubly true.
As previously stated, that yield strength is totally incorrect for that aluminum. Moreover, the yield strength is not the material property that is needed in FEA. He should have the Modulus of Elasticity, which is around 10000000 psi for aluminum. The yield strength is the stress at which the material will fail. The stress in the ASR brace is 8730 psi, and the stress in the Comtech brace is 27000 psi! So this analysis is saying that both braces would break before you even reached this loading condition! And that's not even the combined bending/axial loading that it would likely see!
Basically, everything Tyson's friend noted is correct.
As previously stated, that yield strength is totally incorrect for that aluminum. Moreover, the yield strength is not the material property that is needed in FEA. He should have the Modulus of Elasticity, which is around 10000000 psi for aluminum. The yield strength is the stress at which the material will fail. The stress in the ASR brace is 8730 psi, and the stress in the Comtech brace is 27000 psi! So this analysis is saying that both braces would break before you even reached this loading condition! And that's not even the combined bending/axial loading that it would likely see!
Basically, everything Tyson's friend noted is correct.
10-14-2005, 09:15 AM
#41
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Re: (vtecvoodoo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecvoodoo »</TD></TR><TR><TD CLASS="quote">
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you have no idea how close that is to what i do.....
</TD></TR></TABLE>you have no idea how close that is to what i do.....
10-14-2005, 09:31 AM
#45
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Re: (BA5)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BA5 »</TD></TR><TR><TD CLASS="quote">and the hair.</TD></TR></TABLE>
..and Lazlo living in his closet.
..and Lazlo living in his closet.
10-14-2005, 09:45 AM
#46
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Re: (ECAhatch)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ECAhatch »</TD></TR><TR><TD CLASS="quote">so which is better Comptech or ASR?......</TD></TR></TABLE>
It's a moot point. They both work, neither is better at doing what you're asking it to do. One may be better at doing something else (i.e. withstanding forces that won't be seen in it's intended application) but really, it's a moot point
It's a moot point. They both work, neither is better at doing what you're asking it to do. One may be better at doing something else (i.e. withstanding forces that won't be seen in it's intended application) but really, it's a moot point
10-14-2005, 11:03 AM
#47
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Re: (nonsense)
What is XpressStudy; is it like a student version or something? We're using DesignStar here, never even heard of the Xpress. Cosmos does usually have pretty good correlation to physical data, but it depends on how it's set up.
Regardless, this study is one of the examples that we use at my company to sway people to pay us to do FEA and CFD work as opposed to hiring their own guy. You can have an engineer plug and chug computer models, but if you don't know what you're looking at, or be able to back up the model (or tell when it's wrong) than you're wasting your money. We've had quite a few botched designs come into us, becuase computer modeling was applied wrong.
In any case, there should only be one simulation done using the actual mounting points of the car to determine the stress distrubution. By doing a lateral / side etc force for each, it's not a real world scenario.
Could you plot out what your constraints and loadings are? What was your mesh size, tolerance, growth ratio and boundary restraints? What was fixed, and how were the loads applied? What was the solver method used? In the areas of the I-beams, fin areas and fillets, was there a different mesh used than the rest of the bodies? These things can all have an effect on results.
Regardless, this study is one of the examples that we use at my company to sway people to pay us to do FEA and CFD work as opposed to hiring their own guy. You can have an engineer plug and chug computer models, but if you don't know what you're looking at, or be able to back up the model (or tell when it's wrong) than you're wasting your money. We've had quite a few botched designs come into us, becuase computer modeling was applied wrong.
In any case, there should only be one simulation done using the actual mounting points of the car to determine the stress distrubution. By doing a lateral / side etc force for each, it's not a real world scenario.
Could you plot out what your constraints and loadings are? What was your mesh size, tolerance, growth ratio and boundary restraints? What was fixed, and how were the loads applied? What was the solver method used? In the areas of the I-beams, fin areas and fillets, was there a different mesh used than the rest of the bodies? These things can all have an effect on results.
10-14-2005, 03:35 PM
#48
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Re: (AutoXer)
Does the fact that the ASR have multiple parts ( http://a-spec-racing.com/data/product2_detail.jpg ) affect its strenght? I know for a fact the Comptech is a 1 piece design.
10-17-2005, 01:36 PM
#50
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Re: (vtecvoodoo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecvoodoo »</TD></TR><TR><TD CLASS="quote">
</TD></TR></TABLE>
ROFL ROFL ROFL LOLOLOLOL
</TD></TR></TABLE>ROFL ROFL ROFL LOLOLOLOL