Material inversion using NEML stress gradient

[dewenyushu]

Reason

Gradient-based mechanical inversion optimization problems require the calculation of stress w.r.t. interested parameters. However, automatic calculation of the stress gradient w.r.t arbitrary parameter is not trivial in MOOSE.

NEML2 (which will be available in blackbear soon) has the capability of providing the stress gradient w.r.t. arbitrary parameter as a batch material userobject for a large range of linear and nonlinear materials.

Therefore, gradient-based material inverse problems is possible by leveraging NEML2 stress gradient calculation.

Design

• Create stress gradient batch material (to be obtained from NEML)
• Pass the stress gradient batch material in the material inversion gradient calculation

Impact

Enable material inversion for a large range of materials.