Process-induced deformation of L-shaped variable-stiffness composite structures during cure

Abstract

One of the most key issues for ensuring the accuracy of manufacture and assembly of composite structures reflects on determination of process-induced deformation of composites during cure. In this paper the parameterized investigation on the process-induced spring-in of L-shaped variable-stiffness composites was presented. The Kamal model was used to simulate the cure kinetic for AS4/3501-6 prepregs. A cure hardening instantaneously linear elastic (CHILE) constitutive model was adopted to determine the modulus of the matrix resin. Self-consistent micro-mechanical models were employed to represent the mechanical properties and behaviors of the lamina. The three-dimensional (3D) model of an L-shaped variable-stiffness composite part was established using a linear fiber angle variation. The influence of the corner radius, the fiber orientation, the thickness and the length of flange on the spring-in of the L-shaped variable-stiffness part was evaluated using ABAQUS. The results show that the spring-in angle increases with increases of the corner radius and the length of flange and decreases as the thickness increases; in addition, the layup of 0°±<0°|60°>2S results in the minimum spring-in angle. The present model and method can provide a useful tool for prediction of L-shaped variable-stiffness composite structures.