Bimodulus constitutive models and the simulation on bending properties of woven carbon fibre-reinforced composites

The tensile and compressive properties of woven carbon fibre-reinforced composites (CFRP) are different owing to the buckling and entanglement of fibre bundles. Two bimodulus constitutive models (TBM and PBM) were proposed based on the track stress criterion and principal stress criterion. Combined with the Hashin three-dimensional strength criterion and Alvaro stiffness reduction criterion, a material subroutine was written to calculate the bimodulus constitutive models. Three-point bending tests of [0/90]20 and [+/- 45]20 were designed to obtain the load-displacement curves and failure modes. The precision of the calculation results with the traditional unimodulus model and bimodulus models were compared, and the bending performance of woven CFRP was explored. The results demonstrate that fibre fracture and interlayer damage occur with different stacking sequences. The material properties can be better shown with less error as bimodulus models. The stiffness and strength of the PBM were slightly larger than those of the TBM, and the failure factors were smaller than those of the TBM. The results of the TBM are closer to the test, and the material subroutine is easier to realise. Bimodulus constitutive models have good application prospect in woven composites for higher accuracy.