Minimizing thermal residual stresses in ceramic matrix composites by using particle swarm optimization algorithm

The thermal residual stresses (TRS) induced in ceramic matrix composites (CMCs) with multi-layered interphases when cooling down from the processing temperature, have a significant influence on the mechanical behavior and lifetime of CMCs. The objective of this work is to minimize the TRS of the unidirectional CMCs with multi-layered interphases by controlling the interphases thicknesses. The solution approach combines two numerical analyses: (a) The unit cell finite element models of CMCs with multi-layered interphases are generated and finite element analysis is implemented to determine the TRS. (b) A particle swarm optimization (PSO) algorithm is interfaced with finite element code to find an optimal design and thereby significantly reduce the TRS within CMCs. The classical PSO algorithm is modified to satisfy the variable limits of the optimization problem. In order to obtain the feasible optimal solution, a method derived from the harmony search algorithm is used. Satisfactory results are obtained for a variety of design cases.