Spring-in of composite L-shape specimens: An experimental and numerical investigation
Neoklis Traiforos, M. A. Matveev, Dimitrios Chronopoulos, T.A. Turner
Abstract
The effect of stacking sequence, specimen thickness, tooling material and curing cycle on process induced distortions of L-shape composite structures is investigated experimentally and numerically. Sixty specimens were manufactured, and their spring-in angle was compared against simulation and analytical results. A thermo-chemo-mechanical simulation approach was developed to simulate the experiment by employing a modified Cure Hardening Instantaneously Linear Elastic (CHILE) and a linear viscoelastic material model. Freestanding, fixed and contact boundary conditions were investigated. The spring-in angle of the parts predicted by the modified CHILE material model, was found to be higher than that predicted by the viscoelastic model. The tool material significantly affects the distortion of the parts and contact boundary conditions should be employed for an accurate prediction of the part shape. Balanced, symmetric and thick laminates contribute to a reduction in part distortion, while elevated curing temperatures slightly affect the distortion level of the parts.