Thermal-mechanical coupling-oriented system reliability optimization of composite structures

This paper develops a non-probabilistic system reliability-based design optimization method for composite laminated structures under mechanical - thermal coupling environments. This method improves the traditional method of roughly considering the temperature effect through the humid-thermal amplification factor and precisely considers the thermal stress and temperature effects. In addition, a system reliability analysis method and structural failure criterion for composite laminated structures based on the theory of last-ply failure (LPF) are proposed. The method can calculate the system reliability of composite laminated structures by considering the correlation of multiple failure modes. Finally, non-probabilistic system reliability-based design optimization (NSRBDO) of composite laminated structure system in a thermal–mechanical coupling environment is completed by means of the two-level optimization method. After the proposed optimization strategy is described in detail, two examples of the laminated structure are illustrated, and the results are compared to the traditional design method using the humid-thermal amplification factor, demonstrating the advantages and validity of the proposed method.