Symmetric Three-Directional Optimal Laminate Design

N RECENT YEARS CONSIDERABLE ATTENTION HAS BEEN FOCUSED ON THE Idesign of composite laminates because the weight savings may be obtained by efficient design procedures, and the objective of this paper is to describe such a procedure. Park [1,2] developed a method based on first ply failure criterion or Von Mises failure criterion for simple symmetric laminates. Wurzel [5] considered a design method of symmetric bidirectional composites, namely cross-ply and angle-ply laminates. Tsai and Massard [3] presented principle stress design method and design method by laminate ranking. In this paper we utilize a first ply failure criterion as objective function in optimal design of laminates and ply orientation angles and ply thickness are considered as the design variables. We consider designing three-directional symmetric laminates under various in-plane single loading conditions. Our design