Static strength reliability and sensitivity analysis of large composite structures based on surrogate models

Multiple surrogate models and multiple calculation methods of structural probability of failure were proposed for the structural reliability analysis based on surrogate model. Multiple sensitivity indices were also proposed for the sensitivity analysis of input variables. For the purpose of studying the reliability analysis methods for large composite structures, and studying the differences among different surrogate models and methods to predict the static strength of composite structures of civil aircrafts, a composite elevator of a certain aircraft was taken as an example. The uncertainty of 17 input variables were considered, including mechanical properties, thickness, density and ply angles. Matlab and Optistruct softwares were used to obtain three surrogate models, including Kriging, PC-Kriging and SVR models. MCS and Subset simulate methods were applied to calculate the structural probability of failure. The best surrogate model can be obtained by comparing validation errors. The critical design parameters can be obtained by the importance ranking based on Morris elementary effects and Sobol indices, which is useful for the design of civil aircraft composite structures.