mrashidzafar's blog

I am trying to formulate UMAT subrouting for crystal plasticity. DDSDDE is required to be rotated by DROT or not for anisotropic material?

I am doing a FE formulation of surface elasticity. I wrote UEL for surface elements in addition to abaqus volume elements. But surfaces may have negative stiffness (constitutive relation as per Morton Gurtin's formulation). So as a result I am getting a warning of "Negative eigen values". Can any body tell me how abaqus is solving for this system matrix (with few negative eigen values) in Static General method?

I am only seeing a "x" for a UEL at its first node. And I dont see any other node of UEL. Is it correct or some problem is there?

I also want to calculate the strain energy for whole model(including UEL). But in history output I am only seeing strain energy of Abaqus defined elements under "whole model strain energy". Can some one please help me in calculating strain energy of whole model including UELs