Predicting process-induced distortions in composite manufacturing - A pheno-numerical simulation strategy

Process-induced distortions (PID) of high-performance CFRP structures lead to problems with dimensional control if the distortions are not accounted for by compensating the process tool accordingly. There is a need to predict PID via simulation in industry rather than relying on less reliable information such as past experience or measurements on prototype structures. PID are caused by many phenomena, which can make detailed simulation complex and time consuming. This paper presents three simplified techniques for prediction of PID with sufficient accuracy but that are much faster and cheaper to run than traditional complex process models. The three techniques use solid or shell finite elements and use inputs based on measured spring-in of simple L-angles made of the same material and process conditions as the larger scale structures to be simulated. Application of the three techniques to example structures show that the predictions agree well with each other and that they give good predictions compared to experimentally measured distortions of a CFRP box. Given their speed and simplicity they have the potential to be useful for predicting PID for simpler composite structures, particularly early on in the design cycle where quick approximate calculations are of great value to evaluate different design concepts.