尼龙弹带动态挤进特性试验研究与数值分析

Experimental Study and Numerical Analysis of Dynamic Engraving Characteristics of Nylon Belt

为了研究尼龙弹带在滑膛炮中的挤进特性,设计了短管炮发射装置,进行了动态射击条件下的穿甲弹挤进试验研究。采用瞬态压力测量系统和高速摄像仪得到挤进过程中膛内压力和弹丸运动参量,计算得出弹丸动态挤进过程的阻力变化特性曲线,分析了弹底平均压力上升速率对于尼龙弹带挤进过程的影响。基于试验工况,采用弹塑性大变形的C⁃S模型,数值模拟了尼龙弹带的挤进形变过程,研究了尼龙弹带挤进动力学特性。研究结果表明:尼龙弹带在挤进过程中发生了弹塑性变形,弹带内部为压剪状态,弹带主要失效方式为剪切失效。动态射击条件下的弹丸在挤进过程中挤进阻力随挤进位移的增大先增大后减小;当弹底平均压力上升速率从2.92 MPa·ms^(-1)增大到3.28 MPa·ms^(-1)时,挤进时间缩短了4.36%,最大挤进阻力增大了5.12%;弹丸位移的计算值与测量值的平均误差为5.24%,该三维动态挤进模型可以较好地预测尼龙弹带的动态挤进过程。

The launching device of 105 mm short tube gun was designed to carry out the armor piercing projectile test under dy⁃namic shooting condition.Transient pressure measurement system and high⁃speed camera were used in the experiment to obtain the chamber pressure and projectile motion parameters during the engraving process.The engraving resistance characteristic curves of projectile were calculated by projectile dynamics equation.Besides,the influence of different pressure rise rate on the process of projectile engraving was analyzed under two conditions.Based on the test conditions,the engraving deformation pro⁃cess of nylon belt of armor piercing projectile was numerically simulated by using the C⁃S model with elastic⁃plastic large defor⁃mation of belt material.The experimental data indicated that the engraving resistance increases first and then decreases with the engraving displacement in the engraving process.Therefore,when the engraving resistance reaches the maximum,only part of the nylon belt was completely squeezed.The elasticity of the nylon elastic band increases the contact area with the groove.When the average pressure rise rate of projectile bottom increases from 2.92 MPa·ms^(-1)to 3.28 MPa·ms^(-1),the engraving time shortens by 4.36%and the maximum engraving resistance increases by 5.12%.The nylon belt cross deformation stress cloud dia⁃gram was obtained by the numerical calculation to show that the elastic⁃plastic deformation of the nylon belt occurred.The interi⁃or of the elastic belt is mainly in the state of compression shearing and the main failure form of the elastic belt is tensile shearing failure.The displacement curves obtained by simulation and experiment have the same trend and the error is 5.24%.