An investigation on plastic deformation of rotating band for large caliber gun projectile during engraving process

Abstract

The projectile engraving process of a large caliber gun is investigated by adiabatic process simulation based on smoothed particle hydrodynamics (SPH) and finite element method (FEM). The acceleration, velocity, displacement of the projectile are obtained, and the resistance force and moment applying on the projectile by the gun bore are also obtained. The resistance force varying with the travel of projectile is obtained and the curve reveal a peak in the particular position. At the beginning stage of the deformation, the force increased rapidly and then exhibits a slight transitional drop. The deformation process, equivalent stress, equivalent plastic strain, temperature and damage variable distribution of rotating band are obtained by numerical simulation. In order to visualize the simulation results, two kinds of post processing method are proposed. The frequency distribution of particles was get by particular variables, and the result showing that the maximum temperature of rotating band increment due to plastic deformation can be 150 degrees. Only few material can accumulated to the failure threshold, which indicates that large plastic deformation occurrences in rotating band while ductile fracture does no happen. The second method is to interpolate the field variable on a specified section by developing a program. The results show that the maximum equivalent stress is about 300MPa, the stress triaxility is less than zero, which indicates that most material under compression, and the maximum value of J3 related parameter is 0.5 located at rotating edge, which indicates material under shear loading, which agrees with the function of rotating band.