热应力对身管铬-钢结合面裂纹扩展的影响

Influence of Thermal Stress on Crack Propagation of Chromium-Steel Interface of Gun Barrel

为揭示身管铬钢结合面在热应力下的力学响应及裂纹扩展规律,建立了带有初始裂纹缺陷的不同铬层厚度的身管有限元模型,基于Johnson-Cook损伤失效理论建立了裂纹扩展的模拟方法。从裂纹尖端剪应力和裂纹张开位移两方面分析了不同镀层厚度在热循环下的裂纹扩展,总结了火炮连续高速射击对温度变化及裂纹尖端处剪应力的影响。研究结果表明,单一热应力下,裂纹尖端附近的铬钢结合面剪切应力随着镀层厚度增加而减小,连续高速射击相对于单发射击对裂纹尖端剪应力增长影响不明显,但裂纹尖端位移有显著增长。

In order to study the mechanical response and crack propagation of the chromium-steel interface of the gun barrel under thermal stress,a finite element model of different chromium layer thicknesses with initial crack de⁃fects was established.A damage mechanics finite element method was established by setting contact elements based on Johnson-cook damage failure theory to simulate crack propagation.The crack propagation of different chromium layer thicknesses under thermal cycle was analyzed from crack displacement and shear stress at the crack tip.And,the in⁃fluence of continuous shooting on temperature changes and stress was summarized.The results indicate that the shear stress of the crack tip decreases with the increase of the thickness of the chromium layer.The effect of continuous shooting on the shear stress at the crack tip is not obvious compared with the single shot,but the shear stress at the crack tip increases significantly.