Autodesk Simulation Mechanical and Multiphysics

[#1]

Hello,

I have a part which is falling from 0.5m to the impact plane. The first part of the impact is fine but then the part returns to the original height. Something here is not right. i am attaching the movie maybe someone can eplain why it does that.

Thanks,

Dan 

[#2]

Hi Dan,

I want to confirm what you wrote: "the part returns to the original height". Is it correct that the part returns to the original height?

In the ideal world, there is no energy loss, so the part should bounce indefinitely without losing any height. So the fact that the simulation predicts the same is a good thing!

The file you attached to the post did not include the movie. What version of the software are you using?

[#3]

Hi,

I am using 2013 version of Multiphysics . If you would run the simulation for 5 or 6 seconds you will see the part behaivour. I agree that in  ideal world there is no energy loss and it can bounce forever. The question is how to control that? Can I use a different stifness on impact planes so they will mimic real world?

Thanks,

Dan  

[#4 · Accepted solution]

There is a problem on your load curve.

Gravity in your model is associated with load curve 1.

The definition for load curve 1 is only for period 0~1 second, but your simulation is up to 10 seconds. This implies that there is no gravity from 1 to 10 second, and this is why you see the part flies away.

BTW:

the load curve for gravity should be a constant, instead of ramping from 0 to 1.

The new load curve I suggest looks like this. Please have a try.

[#5]

Damping can be used to control this as well.