Mesh data map for prestrain in FEBio3

[hjs]

Hi all,

I am experimenting with prestrain in FEBio 3.0.2.

I have successfully been able to use the prestrain feature for uniform prestrain (no data map used).
Now I would like use a prestrain gradient "F0" that varies between the elements.
In the plugin for Febio2 there is an example where a non-uniform "F0" is used, but it seems like the data map does not work for this parameter in the new version:

I have tried to put my F0 field in an entry in the meshdata section starting with
<ElementData elem_set="Part1" var="F0">
which gives the error: Can't find parameter "F0".

And
<ElementData elem_set="Part1" var="fem.material('Material1').prestrain.F0">
which gives the error: A mesh map cannot be assigned to this parameter.

I have attached an example where I try to recover the undeformed state of a beam subject to bending using the deformation gradient resulting from an initial simulation.
BeamBending_unload.feb

Does anyone have an idea of what can be done to make this work?

Best regards
Henrik

[maas]

Hi Henrik,

It looks like there are some problems with assigning element data to the prestrain gradient parameters. I will look into it and report back when it is fixed.

If you are interested, I've created a github issue here:

https://github.com/febiosoftware/FEBio/issues/14

Cheers,

Steve