某迫榴炮击针疲劳寿命仿真与提升研究

Simulation and Extension of the Firing Pin Fatigue Life of a Mortar Howitzer

击针大多采用细长及变截面结构,在循环撞击力作用下,易引起结构应力集中及交变应力,经常出现疲劳断裂故障,严重影响自动武器的可靠性,甚至威胁到作战人员安全。某迫榴炮击针在试验中偶发断裂现象,疲劳寿命约200发左右,为了提升该击针疲劳寿命,基于载荷传递过程,建立了击针在火药气体反冲力下高速运动与限位块的瞬态撞击模型,获取击针撞击过程交变应力,通过循环载荷作用下击针疲劳寿命评估,计算击针疲劳寿命与试验现象基本一致,验证了计算模型的准确性。在此基础上,开展了不同材料击针疲劳寿命提升研究,研究表明,将击针材料由PCrNi3Mo更换为30CrNi2MoVE后,击针疲劳寿命由215发提升到1670发,提升效果显著,改进后的击针经实弹射击试验验证在规定寿命周期内未发生断裂现象。

Most of the firing pins feature slender and variable cross-section structures.Under the action of cyclic impact force,it is easy to cause structural stress concentration and alternating stress,and fatigue fracture failure often occurs,which seriously affects the reliability of automatic weapons,and even threatens the safety of combatants.A mortar howitzer occasionally saw its firing pin fracture in the test.The fatigue life of the firing pin is about 200 rounds.In order to improve the fatigue life of the mortar howitzer firing pin,a transient impact model is established for the pin moving against the limit block at high speed under the action of the backward force generated by gunpowder gas based on the load transfer process.The alternating stress of the pin during the impact process is obtained.Through the fatigue life evaluation of the pin under cyclic load,it is found that the calculated fatigue life of the pin is basically consistent with test phenomena.The accuracy of the calculation model is verified.On this basis,a study on the improvement of the fatigue life of different materials is carried out.The study shows that the fatigue life of the firing pins is increased from 215 rounds to 1670 rounds after the material was changed from PCrNi3Mo to 30CrNi2MoVE,and the improvement effect is significant.The improved firing pin has not broken in its life cycle after being verified by live fire tests.