某链式自动机抽壳过程闩体强度失效分析

Failure Analysis of the Breechblock During Shell Extraction for Chain Automatic Gun

作为链式自动机实现开闭锁、击发、抽壳等动作的重要机构,闩体性能直接影响火炮的可靠性。某链式自动机在射击试验抽壳时闩体抓钩断裂,导致火炮停射。针对此问题,这里首先对链式自动机闭锁机构工况进行简要说明;在此基础上采用理论计算和有限元仿真相结合的方法对抽壳过程进行分析,得到两种方法的最大抽壳力相对误差为2.3%,同时得到抽壳力的模拟曲线;最后将得到的抽壳力曲线作为输入条件分别加载至修改前后的闩体上,仿真计算后得到闩体的疲劳寿命。结果表明:现有闩体疲劳寿命为1150.4次,无法满足使用需求,结合理化分析及有限元仿真结果,优化闩体结构、更换材料及改善热处理工艺,优化后的闩体仿真结果显示疲劳寿命达到14504.5次,满足火炮可靠性指标。截止目前,优化后闩体已累计射弹2600余发。

As an important mechanism for chain automatic gun to realize locking,firing,shell extraction,the reality of Chain Automatic Gun is affected by the performance of the breechblock.In the firing test of a chain automatic gun,the grapnel of breech-block was broken when the shell was pulled out,which leads to the gun stop firing In order to this problem,It first gives a brief de-scription of the locking mechanism of the chain automatic gun.On this basis,the method of theoretical analysis and finite ele-ment simulation is used to analyze the process of shell extraction,the relative error of the two methods is 2.3%,the calculation curve of shell pulling force is obtained;Finally,the obtained drawing force curve is loaded into the latch as input condition and the fatigue life of the latch is obtained after simulation Results show that the existing bolt fatigue life is 1150.4 times,unable to meet the demand of using,combined with physical and chemical analysis and finite element simulation results,optimized exist-ing structure,replacement of matericals and improve the heat treatment process,the optimized simulation results show that the fa-tigue life of the breechblock is 14504.5 times,meet the index of the artillery reliability.Up to now,the optimized breechblock has fired more than 2600 times.