thank you for your kind reply. I think that the enforced displacement that you used comes into play as soon as the structure fails. For isotropic ductile materials, I think this should be done as soon as the necking of the material starts. Please tell me if I am right or wrong on this?
Can you please also enlighten me that how would I know that now I should use something extra as an input (like you used an enforced displacement) so that the solver is able to converge after the failure has occurred? Or should we first conduct the analysis without that something extra, and check if the analysis is converging or not, and if it is not, then we need to put that something extra to make it converge?
And one more thing, at t = 0.9 secs when the reaction force is the highest, does this mean that all the applied load is the reaction force there? Or still that is a % of the total applied load? (talking about the situation before the enforced displacement comes into play).