Dynamic mesoscale cracking modeling of energetic composite materials in Hopkinson bar test

Abstract

Dynamic cracking behavior of energetic composite materials (ECMs) is very difficult to be modelled due to the complex microcrack evolution. The microcrack evolution in highly particle-filled composite materials presents asymmetrical characteristics under tension–compression. In this paper, a dynamic mesoscale viscoelastic model taking into account the microcrack growth is developed to simulate the center splitting phenomenon of the Octahydro-1,3,5,7-Tetranitro-Tetrazocine-based ECM Brazilian disc under dynamic loadings by means of the Hopkinson bar test. The microcrack evolution modeling fully considers cracking nucleation, growth and coalescence. The Mohr-Coulomb failure criterion is used to drive the crack propagation. The dynamic cracking formation in the test is captured well. The details of the cracking are analyzed for different loading conditions. The cracking initiation orientation is modelled with different precrack conditions. In addition, the effect of the failure criterion on the dynamic cracking condition is determined. Further, the heterogeneous failure surfaces are considered and compared with the unique failure surface condition.