A rate-dependent peridynamic model for predicting the dynamic response of particle reinforced metal matrix composites

摘要

To predict the mechanical properties and reproduce the dynamic fracturing behaviors of the particle reinforced metal matrix composites, the mesh-free composite models are constructed using peridynamic (PD) theory. On this basis, a rate-dependent PD model is proposed and introduced into the bond-based PD formulation. In this model, the classic Johnson-Cook (JC) equation is modified to characterize the non-linear strain rate effect on the performance of the matrix. The good agreement between the predicted results and the experimental results validates the applicability of the constitutive model. Then we take the thermal mismatch strengthening mechanisms into account for better describing the strong obstacles to the dislocation movement in composite brought by the stacking inclusions. After that, the obtained constitutive model is applied in PD simulations. The unit-particle model is discussed firstly to reveal the damage and failure mechanisms of the composite during the failure process under different strain rate loadings. The results present that the strain rate will change the failure mode and consequently influence the mechanical properties including the ductility and the strength in given strains. Furthermore, the multi-particle models are taken into account, a non-negligible factor, i.e., particle volume fraction, is introduced for systematic study.