An experimental investigation on mechanisms for manufacturing induced shape distortions in homogeneous and balanced laminates

Manufacturing induced shape distortions is a common problem for composite manufacturers. For single curved geometries the phenomenon is known as spring-in. Today a lot of effort is spent to develop modelling tools for prediction of spring-in and shape distortions in general. However, good experimental data is rare in the literature and there are no established constitutive models capable of account for the effect from different cure schedules. In this paper, experimental data for spring-in of glass-fibre epoxy composites are presented. The experiments were performed with angle brackets manufactured by RTM, in a steel mould with accurate temperature control. Different in-mould temperature have been used to point out and separate different mechanisms responsible for spring-in.