抄録
An advantage of carbon fiber reinforced plastics (CFRP) is tailorable mechanical property by changing the lay-up designs since each layer has strong anisotropy. For more effective use of tailorable anisotropy of composites, an idea of using blended layers has recently been proposed. The blended layer has partly different fiber orientation angle in the same layer but straight fiber in each area, resulting in constant volume fraction of fibers. The present study proposes an analytical method for natural frequencies of the laminated plate with blended layers by using the Ritz method based on the classical lamination plate theory. The Ritz method makes it reasonable to conduct parametric study and optimization involving vast number of repeated calculations. The validity of calculation is verified by the comparison of results from the present method and FEM. Then, areas and their fiber orientation angles of blended layers are optimized by using a genetic algorithm to maximize their fundamental frequencies. Numerical results revealed the existence of specific tendencies in the fiber orientations of blended layers on boundary conditions of plate, and the plate can achieve higher fundamental frequencies than those from typical laminates. From above, it is demonstrated that the present method provides good accuracy for the laminated composites with blended layers and the effectiveness of the blended layer design.
