In order to study the influence of structure parameters on process-induced distortions of V-shaped composite parts, a series of experiments were performed to analysis the effect of structure parameters including part thickness, part radius, part angle and lay-up. Based on the shear-lag theory and bending theory, an analytical model considering the effect of structure parameters was developed to predict the spring-in of V-shaped composite parts and the influence mechanism of different structure parameters on spring-in with the model was analyzed. The results show that spring-in decreases with the increase of the thickness and the maximum variation of spring-in angle is about 30% when thickness is between 1 mm and 3 mm. There is a proportion relationship whose value is about 0.014 between spring-in angles and part angle. The differences of spring-in angles which result from different radius are less than 5%. The test pieces with quasi-isotropic lay-up exhibit the biggest spring-in angles. The spring-in angles of 0° lay-up pieces decrease by 23.5% and 90° pieces almost have no spring-in. Analysis results show that the influence of thickness on spring-in should consider its effect on bending stiffness and shear deformation; Mechanical properties and Poisson's effect differences caused by lay-up are the main reasons for spring-in diversity; The maximum distortions of flange is 0.20°which has greatly influences on spring-in. The comparison between simulation results and experiment verifies the accuracy of analytical model.
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