An integrated approach for rapidly and precisely predicting the spring-in of U-shaped composite parts with ply drop-offs

This paper aims to predict the spring-in of U-shaped composite parts with ply drop-offs rapidly and precisely. To this end, an integrated approach was proposed by combining an analytical model for the zones of equal thickness with a proxy model for the effects of ply drop-offs. Firstly, a parametric finite element analysis (FEA) of ply drop-offs was used to collect initial data for the proxy model. Based on these data, the response surface method (RSM) and analysis of variance (ANOVA) were used to determine the input parameters of the proxy model. Then, considering the computational efficiency and accuracy, the radial basis function (RBF) model was selected for ply drop-offs among three data-driven methods to couple with the analytical model for the equal-thickness zones. As the prediction results of the proposed approach were compared with the experimental results, acceptable accuracy was achieved, and computation time was greatly reduced compared to FEA. Consequently, the integrated approach can quickly and accurately predict the spring-in of U-shaped composite parts with ply drop-offs.