Numerical study on dynamic crack propagation of brittle materials by discontinuous deformation analysis

The discontinuous deformation analysis (DDA), as an implicit discrete element method, can simulate the evolution process from continuum to failure by introducing the virtual joint technology. In this study, the DDA method is modified and applied to the dynamic crack propagation problem of brittle materials. Firstly, the DDA with Voronoi discretization is adopted. Since there are many short edges in the Voronoi discretization, these edges will fail preferentially using the original DDA algorithm. A uniform spring algorthim for the DDA is proposed to solve this issue. Then, a parameter calibration scheme is presented. The uniaxial compression and a semi-circular bend (SCB) with a pre-existing crack are used to calibrate the elastic parameters and the strength parameters, respectively. Based on the calibrated parameters, the predicted crack propagation paths of SCB are highly consistent with the test results. Finally, several dynamic crack propagation problems for brittle materials, such as self-similar crack propagation, crack branching and compact tensile tests, are simulated based on the calibrated parameters. The proposed DDA method can reproduce the phenomenon of crack propagation with the constant speed for the self-similar crack and the crack branching phenomenon under dynamic loading. Meanwhile, different failure patterns for compact tensile tests under different loading speeds are reproduced successfully. The results verify the feasibility of the DDA for dynamic crack propagation of brittle materials, and pave the way for future engineering applications.