Finite Element Analysis
Finite Element Analysis
(OP)
I've got a clutch assembly for a performance motorcycle. The goal is to reduce the mass but retain strength and durability. My question is if FEA is the best approach to determine the best compromise for the design of the assembly or if there's a different type of analysis that can answer the question of best design and material use.





RE: Finite Element Analysis
RE: Finite Element Analysis
There is a high level plan. I just want to make sure I'm recruiting someone with the appropriate skills. I don't know much about FEA.
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FEA skills are almost secondary next to good engineering skills.
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This sounds like a FSAE question.
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You definitely do no want someone who's never designed or worked on a clutch design before, as he will most likely wind up revisiting previously reject designs.
TTFN
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RE: Finite Element Analysis
I'll look at the website that's been provided. This may help to get things organized.
I agree that motorcycle engineering have done exceptional work in sportbike engines. Of course with OE products there are additional constraints such as costs which result in products/assemblies that require a great deal of compromise. This is strictly a racing designed product so yes, it does need durability but not to the extent of an OE product.
I've been over to the FSAE board and will also to gather some information from there as well. All though it seems the boards activities has declined over the last year or so.
We already have a prototype that works but I'm sure someone could improve upon the product. The focus is to make it as lite as possible while still retaining a good level of strength and durability. There are a lot of little parts that I'm sure can be improved, such as the clutch springs are very heavy and replacement titanium springs could be made with the same spring rate but less mass. Granted the durability would be reduced but if that's only after say 1k hours of use it would be more than acceptable. Another example is the assemblies housing is aluminum. Perhaps an aluminum alloy / metal matrix or something along the lines of magnesium could reduce the mass and still retain the same level of strength. I'm sure there are more than a few improvements that can be made but accurate analysis work is needed.
Again, thank you for all of the responses.
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And motorcycle clutches just don't weigh that much. Advanced designs might only save ounces - not pounds - and still might blow. Is it that critical??
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The budget for all of this is prioritized as material costs and manufacturing costs as the principal. The design and analysis is of course very sritical but budget wise it's a lower priority. It would be nice if I could find a freelance resource with clutch experience.
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cheers
RE: Finite Element Analysis
RE: Finite Element Analysis
RE: Finite Element Analysis
Let's really abuse that house analogy.
- You have determined that you need a hammer to assemble your house, so you hire a hammer operator and point him at stuff that needs hammering.
- Your nails have been installed. You have installed fence posts around the yard and you have persuaded the electrical inspector to pass your wiring.
- Now it is time to install windows, and you need the hammer operator off site.
I hate analogies. Operating a tool is a good job for a stupid person that you continuously supervise. This does not sound like what you are after.The key to drastically improving performance of something, with a small increase in cost, is to re-design something that does not work properly. People here seem to think that motorcycle clutches are well designed. The bar could be sitting a little high.
Another possibility is that you have a different set of working assumptions, and you can make different design compromises. A drag racing cycle may only need the clutch to survive a half hour between replacements, for example.
JHG
RE: Finite Element Analysis
RE: Finite Element Analysis
TheTick provided some good sites to get me pointed in the right direction. It's obvious that I'll need assistance to recruit the correct individual for my needs.
A jackhammer could be considered a hammer but that's not the experienced guy or tool that I want to use to construct a house.
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Coming from a 5-year FSAE vet, there are much better avenues to pursue to improve your car. The stock clutches on any late model 4-cyl are adequate and messing with the engine internals is almost guaranteed to cause engine failure.
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Here's something to think about though, Suzuki superbike teams add rotating mass their engines (crankshaft) to improve the bike's drivability by providing a more predictable throttle response. This shouldn't be as much of an issue on an FSAE car s you have added drivetrain components that a bike doesn't but making the clutch lighter is going to change its engagement characteristics.
As far as materials, if OEMs are using magnesium and such for engine covers, they've probably though about it for a clutch basket (potential fire issue maybe?).
RE: Finite Element Analysis
TTFN
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RE: Finite Element Analysis
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Finite Element Analysis
I'm sure we can agree that if the engineers who design the motors were given less constraints some parts may have been designed differently and / or alternate materials would be an option. The hazmat materials may be an issue so I am trying to steer clear of Beryllium alloys but not because of FIA restrictions. They're not off the radar completely just not a primary option.
RE: Finite Element Analysis
Several years ago we had to design a heavy duty low speed brake and found the number of design variables small and straight forward. Total torque transmitted is a function of pressure and coefficient of friction of the mating materials, removing the energy (heat) produced can be a challenge.
Rather than use several small springs you might consider a machined spring like these: http://www.taylordevices.com/machined-springs.html Combining the spring shape into the parts could provide a stiffer, stronger, yet lighter part.
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Finite Element Analysis
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Finite Element Analysis
"The application is strictly focused on drag and land speed racing "
Those strike me as wildly disparate forms of racing, aside from needing big HP numbers.
If the stock part is bullet proof I'd spend the money on a suitcase full of carb jets and needles (or a laptop with cables and software for mapping), some dyno time (5800 ft altitude to simulate Bonneville's air density), and a heap of final drive sprockets, and tell my race buddies the clutch is machined from titanium billet with "chrome-moly" inserts to resist denting from the clutch disk tabs
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btw, what's a carb? lol.
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ttp://www
Muzzy's is 630- $760 and includes a fuel shut off feature for smoother shifting. http://www.muzzys.com/MZAS-K12/ Still need a compressed gas bottle, etc.
A 6 inch long 8 diameter hunk of garden variety 6061 could cost over $200 before the machine shop even turns on the coffee machine.
(McMaster CArr 1610T75 Multipurpose Aluminum (Alloy 6061) 8" Diameter, 6" Long - In stock at $232.09 Each )
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ht
http://www.zeroshift.com/transmissions.html
cheers