Multi-step structural simulation -- Is it possible?

[apoynot]

Hi,

Does anyone know how to do a multi-step structural simulation in COSMOS? Essentially, I want to deflect a beam into a pre-loaded state, and then push on it in a different direction. I've done similar multi-step simulations in Abaqus, but can't seem to find the functionality in SWX/COSMOS.

One work around would be to deflect the beam to the pre-loaded state, and then save the resulting deflected beam into a new body, and then run a second analysis on the new body. The trouble with this is that the stress-state is not saved with the new body, and so the second analysis essentially assumes the beam was originally formed into the deflected shape with zero residual stress...

Thanks,
Andrew
Nuventix
Austin, TX

 

[Nader32]

Look at your force/pressure input. You should be able to apply a curve. There are options for loading and unloading. You can vary the force/pressure by "time" and get the results you are after. Make sure the end time is the same as your simulation time.

 

[apoynot]

I actually tried this after I wrote the original question, but it's not behaving like I expect. I created a 2-second simulation time. The first load step is applied as a liner ramp from t=0 to t=1. The second load step is applied from t=1 to t=2. Trouble is, the system seems to be applying both load conditions over the entire 2 seconds. I can't figure out how to get it to ignore one and then the other.

-Andrew

 

[Nader32]

It sounds to me like you picked two surfaces and applied your load curve to both faces. If this were the case it's possible that the load could be cancelling. Do you have one face chosen?

 

[loki3000]

if i understand it correctly, you have to unload the first load at the end of its step/ beginning of the second one.