Optimal Buckling Loads of Nonuniform Composite Plates With Thermal Residual Stresses

Abstract

Optimal elastic buckling loads of spatially heterogeneous plates formed from a series of composite patches is considered. Reissner-Mindlin laminated composite plate theory including thermal effects is adopted for the analysis and the problem is solved using the finite element method based on a bi-cubic Lagrange C0 element formulation. The thermal residual stresses considered are those that result during elevated temperature processing because of the different laminates forming the patches of the plate. In the optimization, the fiber angles in each patch are the design variables and three symmetric laminated plate configurations are investigated. The results illustrate that thermal residual effects can lead to optimal buckling loads which are as much as two times greater than the corresponding optimal buckling loads in which these manufacturing effects are ignored. The work demonstrates the importance of spatial heterogeneity as well as the significance of manufacturing-induced residual stresses in optimal design studies of composite structures.