侵彻弹体结构纵向振动频率特性分析

Analysis of axial vibration frequency for projectile structure in penetration

加速度传感器测试弹体加速度历程时,测试结果包含由于目标阻碍导致弹体减速的过载加速度和弹体结构振动引起的加速度。通过将弹体简化为均匀的长直圆杆,从理论上分析弹体纵向振动的频率特性。利用ANSYS建立了弹体有限元模型,通过模态分析得到了弹体纵向振动对应的固有频率及固有振型,并对弹体进行谐响应分析,一阶纵向振动固有频率的理论值、模态分析与谐响应分析的模拟结果都在1 200 Hz。利用Fourier变换和小波分析,对加速度传感器测试数据的频率特性进行了分析,Fourier变换得到的信号功率谱峰值在1 114Hz,与理论计算结果、模拟结果都能较好吻合。

In the measurement of a projectile＇s acceleration history using an acceleration transducer,the results achieved contain the acceleration resulting from the hindrance of a target that decelerates the projectile and the acceleration resulting from the structural vibration of the missile.In this study,a simple model was established simplifying the projectile as a long straight round bar and analyses the frequency characteristics of the axial vibration of a projectile.A finite element model of the projectile was built using ANSYS to solve the natural frequency and mode of the projectile via modal analysis,then the harmonic response analysis about the projectile was conducted.The theoretical results and simulated results were quite consistent,both about 1 200 Hz.The frequency characteristics of the actual acceleration signal obtained from the target experiment were analyzed via the Fourier transform and wavelet analysis.The peak value of the signal power density spectrum was at 1 114 Hz,consistent with both the theoretical value and the simulated result.