Analysis of progressive failure and structural size effect in fiber-reinforced concrete composite with an improved peridynamic model

In this study, an improved bond-based peridynamic model is proposed to analyze the progressive failure behavior of fiber-reinforced concrete (FRC). The proposed model contains a new bonds degradation law and a damage correction factor to capture the reinforcing effect of fibers, while also considering their random distribution according to the volume fraction. In order to provide a finer description of cracked zones in large structure scales, the peridynamic formulation is coupled with standard finite element theory. The effectiveness of the model and the coupling scheme is validated through two three-point bending test cases, which examine mode I and mixed mode I/II fractures, with varying fiber contents. The simulation results show good agreement with experimental observations, accurately predicting both force–displacement responses and macroscopic crack propagation paths under different configurations. In particular, the proposed model captures the structural size effect and fracture behavior across different geometric dimensions and loading modes, without using any size-dependent parameters. Moreover, it well reproduces the observed trend that the strength of FRC beams increases with fiber volume fraction. • A new bonds degradation law and a damage correction factor are introduced to capture progressive failure process. • Random fiber bonds are combined with ordinary concrete bonds to explicitly describe reinforcement effect. • Peridynamic model is coupled with finite element method for a better description of local cracked zones. • Structural size effects in fiber-reinforced concrete are well described without using any size-dependent parameters.