Coupled 3D non-orthogonal constitutive model for woven composites in preforming and compaction processes

Woven composites are considered promising for lightweight applications with great environmental and economic benefits. One of the most promising techniques for mass-production of woven composite parts with complex geometry is closed-mold thermoforming including preforming, compaction/consolidation and curing steps. The ignored effects on non-uniform thickness deformation and compaction modulus caused by preforming are considered in the coupled 3D non-orthogonal constitutive model to capture the coupled material behaviors during preforming and compaction. The in-plane tension, compression and shear modulus in the model are calibrated using tension, bending and bias-extension experiments, respectively. Meanwhile, the out-plane compaction experiments are designed, with high-accuracy measurement method for the initial thickness and deformation process, to obtain the material properties of sheared woven composites. These experiments can be regarded as one benchmark for compaction tests of woven composites. The new material model has been implemented in Abaqus software and validated by the bias-extension experiments.