Multi-physics coupled prediction method for the interlaminar performance of thermoplastic composites considering manufacturing-induced residual stresses

Thermoplastic composites exhibit high specific strength, weldability and re-formability, which gives them substantial engineering application potential in aerospace and related fields. However, existing studies mainly focus on the influence of processing parameters on crystallization behavior and mechanical performance, while the systematic role of manufacturing-induced residual stresses in governing interlaminar load-carrying capacity and failure modes has been largely overlooked, which prevents an accurate assessment of the structural performance. In this study, a multi-physics coupled prediction method was developed, in which manufacturing-induced residual stresses were explicitly considered based on a crystallization kinetics model and a traction–separation failure criterion. The method was able to effectively describe the interlaminar damage evolution and failure behavior of thermoplastic composites under the action of residual stresses, which was validated by experimental results. The results showed that, when manufacturing-induced residual stresses were included, the relative prediction error of the peak load was reduced by about 60% compared with the case without residual stresses. Furthermore, the study clarified the internal links among the crystallization process, cooling conditions, residual stress field, and interlaminar strength. These findings were of practical significance for forming-process optimization and structural design of thermoplastic composite components.