Abstract: In order to explore the transient impact effect of high-temperature and high-pressure propellant gas on the response to barrel strength, the finite element method is utilized to establish a three-dimensional numerical model for a large-caliber gun barrel. The variation of loading boundary of propellant gas with the projectile motion is defined. The evolution process of non-uniform distribution of temperature field in barrel at different moments under the first firing condition was obtained through numeric computation. The influences of thermal load, pressure and the heat-pressure joint effect on the dynamic stress response of barrel are further investigated, respectively. The calculated results show that the difference of thermal shock loads at different axial positions leads to an axial non-uniform temperature distribution, which makes the axial temperature gradient large and causes a significant axial thermal stress. In the area with intense temperature response, the compressive stress induced by thermal load and the tensile stress induced by pressure incircumferential direction make the stress component act as the interaction between the tensile stress and the compressive stress. Compared with the gas pressure effect, the stress amplitude in the high stress region on the inner wall is weakened, and presents a trend of falling first and then rising with the temperature. Key

Key words: gunbarrel, follow-upboundary, heat-pressurejointeffect, transientimpact, numericanalysis, subroutine