Transient Dynamic Laminated Shell

Dear friends,

I am trying to find thife transient dynamics response of clamped clamped laminated cylindrical shell subjected to Radial impulsive load. I am getting very irregular response using Newmark Integration scheme. But, using HHT-alpha method, high frequency noise from the response gets removed, but damping is intrdoced (Numerical Damping). Although i have not introduced and damping in my model. How to overcome this problem.

I need help in this regard.

Regards