Approximate Method for Buckling of Symmetric Composite Laminates under Thermal Loading

Abstract

In this paper, an approximate closed-form solution is presented to compute the thermal buckling response of a symmetric angle-ply laminates that are clamped in one edge and free along the other edge. For this boundary condition, no exact solution is available and, in order to compute the critical buckling temperatures, numerical methods such as the Rayleigh—Ritz or finite element method must be used. Approximate closed-form solutions bridge the void between exact and approximate numerical solutions and can readily be employed in design optimization. The environment corresponds to a steady state condition providing a uniform temperature distribution for the laminate. The laminate consists of four layers [θ/-θ]s constructed of low, moderate, and high stiffness ratio materials. Comparative results using the Rayleigh—Ritz method provides a means of assessing the accuracy of the expression. For certain laminate architectures, several modes must be computed using the approximate quadratic expression to ascertain the lowest buckling mode, and once identified, provides an excellent approximation for the mode computed using the Rayleigh—Ritz method.