某迫击炮牵引装置限位块仿真分析

Simulation Analysis of the Limit Blocks of a Mortar Trailer

迫击炮牵引装置在行驶过程中,轮胎受到路面冲击载荷作用,使得扭力轴扭转、挡块碰撞限位块,较大的反复冲击会使得限位块发生断裂。为了研究限位块断裂原因,建立了迫击炮牵引装置多体动力学模型,通过仿真计算得到路面行驶状态限位块受力规律,获得了限位块碰撞接触力峰值;建立了上、下限位块有限元模型并进行了冲击载荷下的瞬态动力学分析,得出限位块所受应力最大值以及最大值所在位置,即分析出限位块易断裂的部位。结果表明,上限位块焊缝处最大应力位于焊缝边缘处,下限位块最大应力位于U形弯转处,其值接近材料屈服强度,易发生疲劳断裂。基于此,进一步对限位块进行疲劳分析,结果表明,下限位块寿命远小于上限位块,易发生疲劳断裂。根据疲劳分析结果对限位块进行形状优化,大幅度提高了限位块寿命。

When a mortar trailer is traveling,the tires are subjected to impact load of the road surface,which makes the torsion shaft twist and the stop block collide with the limit block.Larger repetitive shocks result in the break of the limit block.In order to study the causes of the limit block′s fracture,a multi-body dynamic model of the mortar trailer is established,and the loading pattern and the peak contact force of the limit block under the road traveling state are obtained by simulation calculation.Finite element models of upper and lower limit blocks are established.Transient dynamic analysis in consideration of the contact force is carried out to obtain the maximum stress value and its location on the limit block,which means the position where the limit blocks are most likely to break is identified.The results show that the maximum stress at the upper limit block is located at the edge of the weld,and that of the lower limit block is at the U-bend with its value close to the yield strength of the material,which easily leads to a fracture.Fatigue analysis of the limit blocks is performed.The result shows that the life span of the lower limit block is much shorter than that of the upper limit,and fatigue fracture is more likely to occur at the lower limit block.According to the results of the fatigue analysis,the limit block shape is optimized,and the limit block life is greatly improved.