Three-dimensional numerical simulations of dynamic fracture in silicon carbide reinforced aluminum

The three-point bending test by Kolsky-bar apparatus is a convenient technique to test the dynamic fracture properties of materials. This paper presents detailed three-dimensional finite element simulations of a silicon particle reinforced aluminum (SiC_p/Al) experiment (Li et al., [Proceedings of the US Army Symposium on Solid Mechanics]. In the simulations, the interaction between the input bar and the specimen is modeled by coupled boundary conditions. The material model includes large plastic deformations, strain-hardening and strain-rate hardening mechanisms. Furthermore, crack initiation and propagation processes are simulated by a cohesive element model. The simulation results quantitatively agree with the experimental measurements on three fronts: (1) the structural response of the specimen, (2) the time of unstable crack propagation, and (3) the local deformations at the crack-tip zone. The simulations reveal crack propagation characteristics, including crack-tip plastic deformation, crack front curving, and crack velocity profile. The effectiveness of Kolsky-bar type fracture tests is verified. It is shown that a rate-independent cohesive model can describe the complicated dynamic elastic-plastic fracture process in the SiC_p/Al material.