Dear Tohid,
The reason for EA = K_ShrFlp = K_ShrEdg for the BeamDyn input files supplied by NREL for the NREL 5-MW baseline turbine is discussed in my post dated Oct 27, 2016 in the following forum topic: Creating BeamDyn Blade Input - #10 by Jason.Jonkman.
I’m assuming you mean that your model goes unstable with CompElast=2, but not CompElast=1.
I see in your results that Vy is very large and Vx is very large and negative-valued, which are unphysical values. This suggests to me that your model is going numerically unstable for some reason. Again, I would expect a problem in your BeamDyn model. I suggest that you debug by first verifying that your BeamDyn model works well in standalone BeamDyn (e.g. solves properly and yields the expected force-displacement relationships for applied tip loads).
Best regards,