Here, Lij and Ni are linear and nonlinear operators. m is the mass of unit area of the mid-plane, where qx, qy and qz
are the load vectors in the axes directions, while d1, d2 and d3 denote the viscous damping coefficients in the x, y and
z directions, respectively. The explicit expressions of the operators can be found at the Appendix of [21] and [22].
The boundary conditions are considered as all edges are simply supported and given as: