optimization of electronic boards equipped with the bga package to improve the response in random vibration

in this paper deflection and free vibration of sandwich panel is studied. the core of sandwich panels is made of hexagonal honeycomb and faces are made of two different materials of carbon fiber reinforced plastic and k-aryl/epoxy covering. the governing equations are deduced from the first order sheer deformation theory (fsdt) and they are solved using generalized differential quadrature method (gdqm). the classical method in the references is used to verify the dq method and to show that the applied gdqm method has a good results with compared to the references. deflection of sandwich panel is investigated with two different load types. finally natural frequency for the first 4 modes and the two different faces materials are calculated and the effect of various lengths to core thickness ratios and faces to honeycomb core thickness ratios are studied. further, the effect of foundation stiffness coefficient on deflection and natural frequency are showed.