Finite element simulation of the driving mechanisms for cure-induced wrinkles

The presence of wrinkles is crucial for the mechanical performance of the load-carrying laminates in wind turbine blades. Wrinkles can appear or be enhanced by the manufacturing process. This study develops a model for predicting cure-induced wrinkles using a user subroutine for the commercial finite element software Abaqus. The study describes the phenomenon and clarifies how material behaviour is expected to trigger it. A model is built in a 2D plane-strain approach. The fibres and resin are modelled as individual layers in a segmented structure. The resin characteristics include the build-up of mechanical properties and thermal behaviour, such as an exothermal nature, during the curing process. The model shows that for a particular thick monolithic composite, the model can predict the occurrence of a wrinkle. The model prediction of the out-of-plane fibre misalignment angle is of a magnitude severe to the compression strength of the composite.