Large Deflection Elastic and Inelastic Transient Analyses of Composite and Sandwich Plates with a Refined Theory

A C° continuous finite element formulation of a higher order displacement theory is presented for predicting linear and non-linear transient responses of composite and sandwich plates. The geometric non-linearity is accounted for in the sense of von Kar man assumptions and the material behaviour is assumed as elasto-perfectly plastic. The elasto-perfectly plastic material behaviour is incorporated using the flow theory of plastic ity. In particular, the modified version of Hill's initial yield criterion with amsotropic pa rameters of plasticity is used. The layered approach is adopted to account for the plasticity through the thickness of the plate. The displacement model accounts for non-linear cubic variation of tangential displacement components through the thickness of the laminate and the theory requires no shear correction coefficients. In the time domain, the explicit cen tral difference integrator is used in conjunction with the special mass matrix diagonaliza tion scheme which conserves the total mass of the element and includes effects due to rotary inertia terms. The parametric effects of the time step, finite element mesh, lamina tion scheme and orthotropy on the linear and non-linear responses are investigated. Nu merical results are presented for composite and sandwich plates under various boundary conditions and loadings and these are compared with the results from other sources. Some new results are also presented for future reference.