This can be done in the advanced nonlinear solution (SOL 601) for multilinear plastic materials by setting XTCURVE=0 on NXSTRAT.
The default behavior (XTCURVE=1) extends the stress-strain curve via extrapolation. If XTCURVE=0, the curve is not extended and any integration point with a strain greater than the last point on the stress-strain curve is considered to be ruptured and the associated element is removed from the solution.
Thanks. I have read that it is valid only for multilinear-plastic material model. Is there is a way to use a straight line for the stress-strain curve? I would like the stiffness do not change until rupture.
The points in the stress-strain data could form a "nearly" straight line. They just have to satisfy the conditions given in SOL 601 Remark 11 for MATS1