Solid-state explosion simulation in COMSOL Multiphysics

Abstract

In this work, the propagation of blast waves in a rock mass caused by a short-term load is considered. Such loads are typical in the construction of tunnels and other excavations using blasting. For modeling by the finite element method, the cross-platform software COMSOL Multiphysics 5.4 was used. The explosion is reproduced in a steel tank whose steel grade is EN 1.7220 4CrMo4. The medium in the tank has the properties of granite rock (Young’s modulus E = 50 GPa, Poisson’s ratio ν = 2/7, Density ρ = 2700 kg/m3 ). The sphere is also a body having the properties of granite. Set to clarify the geometry of the explosion and the area where the mesh is indicated. The tank has dimensions: 10.39 m in length and diameter 2.9 m. The wall thickness of the tank is 0.01 m. To model the explosion, the Solid Mechanics interface was used, located in the Structural Mechanics branch, based on solving equations of motion together with a model for solid material. Results such as displacement, stress, and strain are calculated. The force per unit volume (Fv) is specified by the normal pressure in the sphere. Also, the tensile strength was calculated for this steel grade: upon reaching a certain pressure in the tank (7.26 MPa), the simulation stops, and the system notifies at what point in time the destruction occurred. A Time Dependent Study is used. Seconds are used as a unit of time. The task is calculated from 0 seconds (initial moment of time) to 0.003 seconds (final moment of time) with a construction step of 0.00005.