Hi all, I am rewriting a VUHARD subroutine written in Fortran using C++. But unfortunately, with exactly the same model and material properties, the results calculated in C++ seem to be missing the elastic part completely. Does anyone know what is going on here please?

For the figure below, the left side is VUHARD written in Fortran and the right side is written in C++. In this test case, all updates are set to 0.1:

//update part code:
// compute yield stress
yield[km] = 0.1; // compute partial derivative of yield stress
// compute partial derivative of yield stress on equi strain
dyieldDeqps[km] = 0.1; // compute partial derivative of yield stress on equi strain.
// compute partial derivative of yield stress on equi strain rate
dyieldDeqps[km] = 0.1; // compute partial derivative of yield stress on equi strain rate
// compute partial derivative of yield stress on temp
dyieldDtemp[km] = 0.1; // compute partial derivative of yield stress on temp