Optimal design of composite laminates with and without cutout undergoing free vibration

In this article, the optimal designs of freely vibrating composite laminates with and without cutout undergoing are investigated. A simple higher order shear deformation theory (HSDT) with four unknown displacements (u0, v0, wb, ws) is employed to obtain the vibration response. A C1 continuity shear flexible element based on HSDT using the Hermite cubic polynomial is used for the rectangular element. The optimisation exercise is performed using genetic algorithms to maximise the fundamental frequency of vibration. The aspect ratio of the laminate, fibre orientation, thickness of plies, modulus are treated as design variables. On the basis of the investigation, it is observed that the non-dimensional frequency of the laminate with cutout can be higher or lower than those of the laminate without cutout depending on the size of the cutout. The presence of cutout significantly affects the frequency. © 2010 The Institution of Engineers, Singapore.