Rahul,
Do you have a screen shot of your model or a hand sketch. Also, as a rule of thumb (good FEA post processing practice) does the deformation (i.e DISPLACEMENT) plot resemble what you were expecting?
"....or do i need to use much big thickness." I thought the idealized aircraft skin had a...
I think the question itself is too general for anyone to provide a specific answer.
Element choice for contact problems depends on ( amongst other factors) whether you are performing a 2D or 3D contact FEA. Also, FEA softwares have different and sometimes unique approach to element formulations...
