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.
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Finite Element Analysis 1
- Thread starter kwklein
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Thank you for the response. That's the answer I was looking for. I needed to confirm that I wasn't asking "should a house need walls?"
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.
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.
Yeah, that's a tough one for an FEA outsider. It would be best if you could find someone to consult with to flesh out job requirements. I recommend <
FEA skills are almost secondary next to good engineering skills.
FEA skills are almost secondary next to good engineering skills.
Motorcycle engineers have done a fantastic job with late-model sportbike engines. I think you'll have a hard time making a better overall clutch package than the bike is equipped with from the factory. What you lose in weight you'll probably also lose in feel/driveability and reliability.
This sounds like a FSAE question.
This sounds like a FSAE question.
Philosophically, I would vote for specifically clutch design experience, rather than straight FEA experience. It sounds like you need someone who started as a carpenter, but is currently a general contractor, to carry the house analogy a bit further.
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
FAQ731-376
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
FAQ731-376
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These are all great responses and I really appreciate the input.
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.
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.
MiketheEngineer
Structural
From an old structural guy - use the factory one - its proven...
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??
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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TheTick - that second site contains liturature and event information. Yes, I would like to understand things in more detail but I'm relying on the "other person" to already have the knowledge / ecperience / expertise.
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.
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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Another Consideration: How much more weight do you need to remove? You can perform an absolute perfect FEA analysis and then have your part break because the load input estimation was wrong. If you're trying to save 5% on material costs but you have a factor of safety of 2 on your load estimates then you might be better served getting better load estimates. All it takes is one severe overload to break a part designed to its limit or ruin a fatigue life estimate.
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BobM3 - That's a very good point. I hope alot of these scenarios can be fleshed out during the analysis. The load estimates will have a certain margin included in the calculations. The initial shock during launch and then the shock during each shift will all have to be considered. It would be great to discover all of this during the analysis phase but I suspect that one or two assemblies will suffer catastrophic failure. There isn’t a set goal as far as the total mass reduction. It’ll need to be determined if the reduction is cost effective. I don’t want the final costs of the product to triple and only result in a very small increase to the performance aspect.
kwklein,
Let's really abuse that house analogy.
[ol]
[li]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.[/li]
[li]Your nails have been installed. You have installed fence posts around the yard and you have persuaded the electrical inspector to pass your wiring.[/li]
[li]Now it is time to install windows, and you need the hammer operator off site.[/li]
[/ol]
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
Let's really abuse that house analogy.
[ol]
[li]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.[/li]
[li]Your nails have been installed. You have installed fence posts around the yard and you have persuaded the electrical inspector to pass your wiring.[/li]
[li]Now it is time to install windows, and you need the hammer operator off site.[/li]
[/ol]
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
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Drawoh – I’m not big on analogies either. Maybe that’s why I seemed to lose sight in your analogy. You did summarize what’s being done. It’s a redesign of the current already modified clutch assembly. I do admit that the OE clutch assemblies are well designed for their purpose and the parameters that are established for them. A lot of additional compromise needs to be made with the proposed redesign. The assembly should have some durability and not require constant replacement but it doesn’t need to live nearly as long, uninspected for thousands of miles, in any and all conditions. The design that’s being tailored can be categorized as a top shelf performance modification. In the tiny area of no sponsorship motorcycle racing the clutch is a very important part of the complete formula and consumers will practically throw money at you for the so called “best one”.
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.
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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