volume regions and elastoplatic analysis

[ozzkoz]

I'm having trouble getting my analysis to run. I've added volume regions to my FEA model so I can refine my mesh in the area of interest and set up both a linear and nonlinear anlaysis. The linear static analysis runs fine and completes (using the elastoplastic properties). The nonlinear anlysis tells me that there are elements which have not been assigned properties. If I supress the volume region the nonlinear analysis runs correctly. I've tried assigning materials to both the component and the volume but this hasn't solved it. Does anyone have any ideas? The whole point of a volume region

 

[ysm]

One way to refine mesh is using datum points. Create datum points around the area of interest. Make sure the datum points are not collinear.

HTH
ysm

 

[ozzkoz]

I can refine my mesh in a number of ways but there are a few nice things I can do with volume regions. If it is possible to do an elastoplastic analysis and use volume regions I'd like to find a way to do it. It seems simple enough as I just need to learn how to apply the material correctly (or so the program tells me)

 

[ysm]

You probably have already done this but just in case...
As a check can you cut away everything else except the volume region and run a simple analysis to see if it accepts material properties.

 

[ysm]

I just tried a simple bracket and it works. I am not sure how complicated your model is.
I created a bracket and performed a non-linear analysis (without a vol region)
Then added a volume region along the radius and performed another non-linear analysis and it went through fine.

 

[ozzkoz]

hmm, must be specific to my model. I'll have to try on another model. I seem to get strange behavior form my system now and again. After an analysis it will sometimes refuse to show results, and I've had trouble exporting images.

 

[ysm]

Yes i have seen those two problems in WF5.0
after an analysis it refuses to show the results window. it works if i go to "Display Definition(s) from selection" icon and select the window, then the results window shows up.
Also, are you using any autogem setting on the volume region. If you like I can try that setting on my bracket and see.

 

[ozzkoz]

I'm using the mesh refinement to set the maximum element size in the volume. In my case .040.

 

[ysm]

I set the same max element size in the volume and it went through fine.

 

[ysm]

ozzkoz,
Is it possible that your volume region is going beyond the material (by a very small amount) and hence that part of the volume region is not associated with material and its properties?

 

[ozzkoz]

My volume does extend beyond the solid model, but I've had this work before. I think the problem is related to simplified reps. I de-featured my model by making an FEA Representation and excluded things that wouldn't effect the result but would add complexity. I changed it to use family tables to remove those features and it worked fine today. I'm guessing the volume region acts on the model geometry itself but the mesh was being built on the simplified rep and there was some disconnect.

Thanks for your help.