基于能量谱的爆炸冲击波毁伤特性研究

摘要

The energy spectrum is an effective characteristic parameter to evaluate explosion shock wave.Tests show that the higher the energy spectrum within a frequency band of explosion shock wave,the better the damage effect of target within the same frequency band.In order to study the explosion shock wave energy spectrum features,two groups of tests were designed to measure explosion shock wave pressure signals for the same explosive with different blast central distances,and different explosives with the same blast central distance.To accurately extract energy spectrum from these presure signals,an improved HHT energy spectrum extraction method based on wavelet packet was put forward.To eliminate the effect of noise on the energy spectrum,the wavelet packet was used to filter the original signals.Further, correlation coefficients between intrinsic mode functions (IMFs)and the filtered signals were introduced to screen effective IMF components.The results showed that the improved HHT method can improve the calculation accuracy and velocity of energy spectrum.Through analyzing the explosive shock wave energy spectra under different operation conditions,it was found that the low-frequency band energy has larger damage range and decays slowly with increase in distance;In contrast,the high-frequency band energy has a weaker damage effect and decays fast with increase in distance;at the same time,different explosive types'shock wave have different energy distributions,higher frequency energy and lower frequency one have significant differences.Thus,the above laws provided a new idea for evaluating warheads'damage effects.%能量谱是评价爆炸冲击波的重要特征参量，大量实验发现爆炸冲击波在某频段内的能量谱值越高，对自振频率在相同频段内目标的毁伤效果越好。为研究爆炸冲击波的能量谱特性，设计了2组对比实验，分别测得同种炸药在不同爆心距及不同炸药在同种爆心距的爆炸冲击波压力信号。为准确提取爆炸冲击波信号中的能量谱，提出了一种基于小波包的改进 HHT（希尔伯特－黄变换）能量谱提取方法。针对噪声对能量谱特征的影响，采用小波包对原始信号进行滤波，结合 IMF（固有模态函数）分量与滤波后信号的相关系数，筛选出有效 IMF 分量，结果表明改进 HHT 方法提高了能量谱计算精度和速度。通过分析不同工况下爆炸冲击波能量谱发现，爆炸冲击波低频段能量随距离的增加衰减慢，毁伤范围大；高频段能量随距离的增加衰减快，毁伤效果较弱；同时，不同类型炸药的爆炸冲击波具有不同的能量分布，高频能量与低频能量可有明显差异，以上规律可为战斗部毁伤效能评估提供新的思路。