It seems that in case of blank parameters left in the em category of MAT/LAW36, the software extrapolates the stress strain curve ( a conservative assumption). However if you want the material to stop effecting the system as soon as the limit is reached, don't forget to put the respective em value in the card. Another workaround is to provide a complete stress strain curve where the stress goes from zero to zero. I personally prefer the later method as it leaves no scope for any more confusion. #Was this helpful?