Non-Linear (Force/Displacement) Curve

[MahReda]

Dear Sirs

I'm quite new with dealing with ansys

I'm working now on a on-linear analysis

i followed alot of tutorials on internet and followed them step by step

i'm seeking to plot force against displacement in a graph

in my thought that the curve should have positive slop and go up until the point where the maximum load that the model can sustain and then the curve will start to go down where the material start to enter the plasticity region then fail

but i get only curve like attached one .... no negative slop

and when i try to increase the applied force i get error that some nodes has great distortion

i'm doing the analysis on a simple plate with dimension of 1000 X 1000 X 2 mm

fixed from one edge and the load of 900kn in applied from the opposite edge

i'm looking for help to continue my study

best regards