Characteristics analysis of failure envelope for fiber‐reinforced plastic and its dependence on the ratio of uniaxial strength

Abstract This study investigates the characteristics of the FRP failure envelope under combined compression‐shear loading, basing on experimental, theoretical and simulation analysis. The observed discrepancies in the PUCK criterion are shown to depend heavily on the ratio of transverse compressive strength to longitudinal shear strength. Meanwhile, the representative volume element (RVE) models are employed to analysis microscale factors influencing the FRP failure envelope. The results indicate that the failure envelope is significantly influenced by the interface reinforcement coefficient, which is strongly correlated with the ratio of uniaxial compressive strength to shear strength. The significance of this ratio lies in its macroscopic reflection of the interface reinforcement coefficient, and errors can be decreased by modifying the failure criterion according to this ratio. This main finding of this work is to reveal the dependence of the FRP failure envelope on the ratio of uniaxial strengths. On this basis, the optimal values for the inclined angle parameters in the PUCK failure criterion are proposed in relation to FRPs with varying interface reinforcement coefficients, which offering valuable insights for improving the accuracy of FRP failure predictions. Highlights The interface reinforcement coefficient can influence biaxial failure envelope. Improving the slope parameter can considerably lower the prediction error. Dependence of failure envelope on the ratio of uniaxial strength was clarified.