Nonstationary response system for the stepped composite cylindrical shell with drop-off ply under moving random loads

The present work primarily aims to provide a general stochastic vibration system for the stepped composite cylindrical shells with drop-off ply subjected to moving loads. By performing the first -order shear deformation shell theory (FSDST) and Hamilton's principle, the theoretical model is established and the stationary/nonstationary stochastic responses are solved by integrating the pseudo excitation method (PEM) into the method of reverberation -ray matrix (MRRM). Meanwhile, the unsymmetrical drop-off ply configuration is realized by considering a balanced relationship through the artificial virtual springs at the coupling point. The novelty lies in the sequential action of moving random load on non -uniform stepped cylindrical shells in the form of concentrated or distributed, and a unified full -domain response formulation containing the nonhomogeneous excitation equation is provided. The comparison of the stochastic vibration response curves and deformation diagrams with the finite element simulation demonstrates that the current method is effective for various stochastic dynamic problems. On this basis, the differences between the unsymmetrical/symmetrical drop-off ply configurations under moving random loads are first visually discussed, and the effects of the load and geometric parameters on the power spectrum density (PSD), frequency response bandwidth and time -varying root mean square (RMS) are further revealed.