针对自动步枪在冷热枪状态下的差异,为揭示冷热偏机理和提高射击精度,以某典型小口径自动步枪为研究对象,基于热固耦合的研究方法,计算了镀Cr层但忽略膛线的某典型小口径自动步枪枪管系统在连续热冲击及膛压下的瞬态温度及变形,分析了其温度场和沿径向的位移场变化规律,仿真计算结果获得了试验数据的验证.研究表明:连发发射时内膛薄层各点的温度梯度将引起高频急剧变化的热应力;热载荷是影响残余位移的主要因素;枪管系统前几发弹峰值位移主要受脉冲位移影响,随着射弹量增加峰值位移主要受残余位移影响;随着射弹量增加,热枪状态下枪管系统变形明显大于冷枪状态下变形;热载荷是影响枪管系统变形的主要原因,膛压对枪管系统产生了位移脉冲,不影响残余位移.残余位移的增加量随射弹量呈减小趋势.%Aiming at the difference of automatic rifle under the conditions of cold and hot gun,a typical small-caliber automatic rifle was taken as the research object in order to reveal the mechanism of cold and heat deviation and improve firing accuracy,and the research method based on thermal-solid coupling was used. The transient temperature and deformation of a typical small-caliber automatic rifle barrel system coated with Cr layer but ignoring the rifling were calculated under continuous thermal shock and chamber pressure. The variations of temperature field and displacement field along radial direction were analyzed. The simulation results were verified by the experimental data. The results show that the temperature gradient of each point in the inner chamber layer can cause a sharp change of thermal stress in high frequency during continuous firing;the thermal load is the main factor affecting the residual displacement;the peak displacement of the first few projectiles in the barrel system is mainly affected by the pulse displacement. With the increase of projectile quantity, the peak displacement is mainly affected by residual displacement. With the increase of projectile quantity,the deformation of barrel system in hot gun state is obviously larger than that in cold gun state,and the thermal load is the main reason affecting the deformation of barrel system. The pressure on the barrel system generates a displacement pulse that does not affect the residual displacement. The increase of residual displacement decreases with the amount of projectile.
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