冷热枪状态下弹枪相互作用的热力耦合分析

为了研究在冷热枪状态下弹枪的相互作用,以某型自动步枪的铜被甲弹丸与枪管为研究对象,建立了其相互作用的热力耦合有限元模型,模型结合了考虑温度对摩擦因数影响的摩擦力子程序以及基于火药燃烧过程的内弹道载荷子程序,对弹丸温度变化及其在全枪管中的运动进行了数值仿真分析。结果表明:冷枪时,铜被甲弹丸表层升温在200℃左右;400℃及700℃的假设热枪状态下,刚完成挤进时铜被甲弹丸表层温度已经接近熔点,在膛内运动过程中表层铜材料剥落,枪管内膛会出现了"挂铜"现象;另外,热枪状态下弹丸在膛内的攻角变化明显大于冷枪状态下的攻角,不仅印证了热枪射击精度比冷枪射击精度差,也揭示了造成此现象的机理:由于高温下铜被甲圆柱部材料软化脱落,变形不规则,造成弹丸在膛内及出膛摆动增大。

The interaction between copper jacket projectile and barrel under different temperature based on thermo-mechanical coupling finite element model

In order to investigate the temperature and motion state of copper jacket projectile in the barrel, a thermo-mechanical coupling finite element model of the barrel and bullet was built. In the model, a friction subroutine was developed to calculate the value of the friction coefficient between projectile and barrel at different contact temperature.The pressure of gunpowder gas was carried out by a load amplitude subroutine embedded interior ballistic equations. The results show that the surface temperature of copper jacketis up to about 200 ℃ after engraving into the bore when the barrel is room temperature. When the barrel is high temperature(Setting as 400 ℃ and 700 ℃ in the model, respectively), the surface temperature of copper jacket is close to the melting point of copper material and the surface material will break off during the movement in the bore. In addition, the change of the attack angle of the projectile in the bore under the condition of hot barrel is obviously greater than that under the condition of the room temperature barrel, which proves that the shooting accuracy of the hot barrel is worse than that of the room temperature barrel.The mechanism of this phenomenon is when the barrel is high temperature, the surface copper material will be softened. When the projectile engraves into the bore, the surface copper will be peeled off from the copper jacket. It causes the irregular deformation of copper jacket and a large swing of projectile in the bore.