基于ANSYS/LS-DYNA的击针撞击应力数值仿真

Numerical Simulation for Pin Impact Stress Analysis based on Ansys/LS-dyna

本文针对自动武器中重要但又容易出现断裂的击针,从应力分析的角度出发,利用有限元分析软件ANSYS,建立了击锤撞击下击针应力仿真的有限元模型,计算得到了击针的应力、速度、位移等参数.从仿真结果可知,击针的危险断面不在击针的尖端,而在距离尾端约15 mm处,这与击针实际发生破断的位置相一致,说明该仿真方法能够较真实地模拟击针的应力分布状态.危险断面内的最大应力并没有超过材料的屈服极限,所以击针的断裂不是因为瞬间应力过大引起的,而是在交替-拉压应力的作用下疲劳破坏的,因此,要提高击针的寿命,首要的是提高接近尾端区域的表面质量,减小应力集中以降低循环应力的幅值.

Aiming at the important and liable to freacture feature of pin in automatic weapon, the simulation model of pin＇s stress in preimer impact is built and the pint stress, velocity and displacement parameters are calculated using the FEA software of ANSYS from the argle of stress anilysis The results show that the dangerous section is not the pin head but lies in the location which has a 15mm distance to the head and it is consistant with the actual test result, and it also show that this method can analysis the pin stress. The dangerous sectioin stress not exceeds the materialt yiels limit,so it can be deduced that the pint fracture is not due to huge stress but due to tensile-compression fatigue. In order to increase the pin＇s life, it can improve the surface quality near the pin tail to decrease the stress cycle magnitude firstly. The analysis mentioned aboved can give some reference for pin improve design.