PHYSICS-BASED SIMULATION WORKFLOW FOR STAMP FORMING OF THERMOPLASTIC PARTS

Stamp forming of thermoplastic composites provides an opportunity for the automotive industry to manufacture light-weight components with superior mechanical properties while achieving a reduced cycle time. Prior to stamping, continuous fiber preforms, called blanks, are consolidated on a press. The forming process entails heating the blanks to a processing temperature, quickly shuttling the blanks to the press, and forming the part with a heated, two-sided mold. The forming pressure is held on the part until it cools to a solid state, and then it is ejected from the tooling and continues to cool to ambient temperature. This paper presents a physics-based simulation workflow for the forming, heat transfer, and subsequent part deformation of a thick, double-curvature part made with CF-PEKK. The forming process and any subsequent wrinkling and fiber reorientation is captured with the software AniForm. The updated fiber angles from the forming simulation are used as inputs for a sequentially coupled thermo-mechanical analysis in Abaqus, which predicts the temperature and crystallinity history of the part during forming and cooling. These results are fed into a mechanical analysis which captures the build-up of residual stresses and subsequent relaxation and deformation of the part as it cools outside of the tool. Finally, the predicted deformation is compared to the experimentally measured warpage of a part made with this manufacturing cycle.