Difference between results of Linear static and Non linear quasi static.

Hello,

 

I was carrying out analysis on a model in which load vs deflection results were to be found out.

 

Material was defined by MATHE card with stress -stretch curve , and some contacts were present.

 

First I used Linear static loadstep and then I used Nonlinear quasi static step for same model and BCs.

 

Results of both cases were very much different (more than 50%).

 

Can anyone tell me what is the case?Is linear static neglecting the effects of contact and material non linearity?

 

Regards,

Bharat