Numerical simulation of double-hole crack propagation under explosion load

Here, to study crack propagation law of double-hole explosion, taking the plexiglass material polymethyl methacrylate (PMMA) as the medium, crack propagation of double-hole explosion with no guide hole, ordinary guide hole (empty hole) and grooved guide hole under different hole spacing L oil, 9, 11, 13 and 15 cm was numerically simulated by using the finite difference software AUTODYN. The linear state equation and Johnson-Holmquist (JH-2) constitutive model were used to describe the volume and bias, and the tensile fracture softening model was introduced to further describe explosion crack effect. In order to verify PMMA material model and physical parameters, single-hole crack propagation was simulated firstly, and the results reproduced behaviors of crack crushing zone and crack zone, radial crack and circumferential crack, crack initiation, propagation, bifurcation, crack arrest and secondary propagation. The applicability of the material model and physical parameters was successfully verified. The simulation results of dual-hole explosion crack propagation showed that in the case of no guide hole, the hole spacing L is the most important influencing factor of crack penetration, and the penetration mode belongs to tensile cracks active inter-penetration; guiding action of ordinary guide hole or grooved guide hole is reflected in stress concentration and shortening crack penetration distance; when the hole spacing L is constant, the empty hole size effect is conducive to crack penetration in a certain range; for crack directional propagation effect, the guiding action of grooved guide hole is the strongest, followed by ordinary guide hole, and no guide hole is the worst; the crack penetration mechanism is reflected in 3 aspects of penetration position, penetration crack type and penetration mode. © 2022 Chinese Vibration Engineering Society. All rights reserved.