Inquiry about outputing the total deformation gradient on each node about crystalplasticity HOT 3 CLOSED

Hi Richard,
You are right, there is not an available variable for the deformation gradient.

It is readily available in UMAT as DFGRD and DFRGD0 at the current and former time increments. We have left empty places in userouputs to allow users to define their owm outputs. It would be in this case similar as the definition of thermal or plastic deformation gradients. You may need to do some modifications in globalvariables.f, initializations.f, and useroutoutputs.f files.

Best,
Eralp

from crystalplasticity.

Dear Eralp:

May I ask a question about remeshing? Suppose that I get a result of CPFEM after some iterations using your UMAT, then I perform remeshing because of the bad quality of mesh. So the next step is to interpolate all variables onto the new mesh to construct the stiffness matrix of FEM, and then we can continue the simulation. May I ask which variables I need to store and interpolate to the new mesh? Whether your UMAT can achieve this? Thank you very much!

Regards,
Richard

from crystalplasticity.

Hi Richard,

The software in its current form is not designed for adaptive meshing. It is usual to decide on the mesh refinement level through a mesh convergence study, then this level is used for the simulations.

The state variables are not stored in standard STATEV vector of Abaqus so, the sub element properties will need to be assigned from global variables. This may likely require a user subroutine "UMESHMOTION" to decide element division and assign its properties together with UMAT.

The alternative is to use STATEV and let Abaqus deal with the assignment of element properties of element subdivision.

Both require a lot of work and modifications in any case.

Hope this helps,
Eralp

from crystalplasticity.