FINITE-ELEMENT TRANSIENT ANALYSIS OF COMPOSITE AND SANDWICH PLATES BASED ON A REFINED THEORY AND A MODE SUPERPOSITION METHOD

Transient dynamic response of composite and sandwich plates is obtained using a recently developed refined shear deformation theory and mode super-position technique. The free vibration response is computed using the generalized Jacobi method with a sub-space iteration technique and then the mode shapes are used for computing the dynamic response. A special mass lumping procedure is used in the dynamic equilibrium equations. Duhamel's integral is used for the time integration of uncoupled systems. The method leads to considerable saving in computation time during computer implementation for the same order of accuracy in results as compared to direct integration methods. Numerical examples are solved for different types of dynamic loads and the results compared with those available in the literature. The mode superposition method has given good results and at the same time there is considerable saving in computer time. Unlike direct numerical integration techniques, here the time step requirements are only for obtaining the variation of displacement and stress resultants with time and for closely approximating the time dependent forcing function during numerical integration of single degree of freedom modal equations.