Validation and verification of a novel higher-order FE Framework for process modeling of thermoset composites

Uncontrolled curing-induced residual stress is a significant limitation to the efficient design of thermoset composite structures, and a sufficiently high post-cure stress state can compromise their performance, durability, and geometrical tolerance. Experimentally validated multiscale process models aid in quantitatively describing the relation between process parameters and residual stress development across composite length scales, thereby allowing for an optimized manufacturing process and improved part performance. This work presents a novel numerical approach for the process modeling of fiber-reinforced thermosets, and is based on higher-order finite elements derived from the Carrera Unified Formulation. The process framework is experimentally validated at the macro-scale using cure-induced warpage data of fabricated cross-ply laminates. Micromechanical process analysis is performed to predict residual stress evolution at the micro-scale, and a comparison with reference 3D-FEA provides a verification of the proposed approach. The predicted laminate-level cure-induced warpage is found to be within 9% of experimental measurements, thereby validating the presented process model, while comparing the micromechanical analysis costs with conventional 3D-FEA demonstrates an order-of-magnitude improvement in computational efficiency. The performance of the proposed computational models constitutes a milestone towards enabling practically feasible multiscale process modeling for composites structures.