Modeling of Compression Spring exposed to cyclic loading

If all you are doing is testing the spring, there are mathematical formulae that can predict failure based upon # of cycles, amount of compression, ect. There is also software that automates the process of doing the math so you can test lots of design/material changes in the time it would take to run it through a std analysis pkg.

If you are trying to simulate motion, there are some things that can be done in the assembly simulation, but I don't see how to cycle stuff other than putting the playback in a loop. If you want to get real complex, you can drive the dimensions of your spring with equations, and a little VBA to force it to cycle.

Someone's site ( maybe Ed's? ) has an equation driven spring sample.

Ed's site appears to be down. I'd also be interested in seeing this example if someone can host it.

-Matt

Brian wrote:

I'm kind of curious if I am the Ed you are referring to. I had posted on a few springs to a personal site about a year and a half ago, but I let that site lapse (lacked the time to do anything with it. Now that its cold I might actually do something with it).

The springs were not accurate for engineering testing. I would also recommend the formula or to put your spring vendor to work for you in developing the apporpriate spring for the job. But the files were a useable springboard for animations and for interference detection. If you want those files, email me at work (the email I use for google groups has also lapsed)

EdEaton At DimonteGroup Com

Velu,

I am not quite sure how SolidWorks can expose a spring to cyclic loading. If by your question you mean how is a spring set up for analysis of fatigue and stress evaluation in CosmosWorks I will respond by saying that this is not the best way to solve the problem. In the words of one of my professors, "It is driving thumbtacks with a sledge hammer." Spring manufacturing associations have software that will do this type of analysis quickly and much more accurately than CosmosWorks can do. Your spring manufacturer will usually have this software and will check your design anyway. This is a case where even a textbook solution is superior to doing FEA.

If you are simply asking how to represent the spring in a model in both compressed and uncompressed states then I would search the newsgroup because this has been discussed many times.

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You're probably remembering the various examples of springs on Mike Wilson's site: