Effective Strain is doomed in my 3D bone model

[ashkansed]

Hi,

I'm a graduate student and new to FEBio. I tried a compressive strength simulation for my model with a fixed bottom in (Z, X, Y) and rotation (Z, X, Y) for the upper surface is a free Z ( only X, Y) and fixed (Z, X, Y). I used a prescribed displacement of -1 and freedom degree in the Z-axis. After the 9th run, I got a negative jacobian. The displacement is shown correctly. But the effective stress and strain are doomed into a small triangle in Postpreview map attached below.

It would be appreciated if you might help me!

DisplacementJPG.JPGstress.JPG

Four.log

[maas]

Hi,

As far as the negative Jacobian goes, I'm not sure what caused it without seeing the model, by my guess is that you might have run into a buckling mode given that you are doing a compressive load.

As far as the color map goes, the element that has the stress concentrations is probably the one that is about to invert. If you just want to adjust the color map so you can see the stress distribution in the rest of the model, you can do that as follows:

1. Go to the Model panel, find the "Color Map" item in the tree and select it.
2. In the properties list below, set the range type to "user".
3. Set the User max and User min fields to suitable values.

I hope this helps.

Cheers,

Steve