Interaction mechanism between shock waves and a movable cover of explosion venting vessel connected with shear pin

Abstract

Based on a pin-connected explosion venting vessel, the interaction mechanism between shock waves and a movable cover was studied numerically and theoretically. The numerical model of the vessel was established with LS-DYNA software to study the propagation of the shock wave and the motion of the cover during venting process. For the breaking diameters and failure morphologies of the shear pin, there is a good consistency between simulation and experiment, verifying the effectiveness of the numerical model. According to the kinetic energy theorem, the theoretical model was established to illustrate the relationship between the work done by shock waves and the energy of the shear pin and cover. The numerical results show that the motion of the cover can be divided into three phases: initial acceleration under the load of shock waves, deceleration due to the constraint of the shear pin and re-acceleration after the shear pin breakage. Moreover, It was concluded that explosion energy released by TNT is mainly converted into the internal energy of the shear pin and kinetic energy of the cover, besides the energy of the air. When the shear pin is broken, the kinetic energy of the cover reaches its valley, which is about 0 kJ under critical conditions. The theoretical model effectively reflects the square root relationship between the breaking diameter of the shear pin and the TNT mass under critical conditions, the shortcomings of the model were also discussed. The present study can provide references for the design of explosion venting structures.