基于爆炸火光光谱分析的大当量爆炸场破片速度测试方法研究

A Method to Measure the Velocity of Fragments of Large Equivalence Explosion Field Based on Explosion Flame Spectral Analysis

为了解决战斗部爆炸过程中,因爆炸物当量较大造成爆燃火球持续时间长,覆盖面积大,近场位置破片速度参数难于获取的问题,提出一种以激光光幕为有效传感区域的光电收发一体的测试方法。通过分析三种不同类型战斗部爆炸火光特征光谱分布可知,在0.3~1.0μm波段内火光相对光强度较低。以此为依据,采用定距测时原理和原向反射技术,由固体激光器、菲涅尔透镜、窄带滤光器、高速光电传感器等关键光学元件构建破片速度参数获取的光学系统。系统光路收发一体,结构紧凑,窄带滤光片与激光光源配合使用避开火光光谱,有效抑制背景光的干扰。采用该系统进行了不同型号、当量的战斗部静爆破片速度参数测试现场实验,通过美国NI数据采集系统记录数据并对信号进行去噪和识别,成功获取了较高信噪比的波形信号。实验结果表明：本方案可完成爆心10~15 m附近破片速度的准确测试,最小可测破片尺寸为4mm,获取破片速度可达1 200m·s-1,与靶板测试结果对比可知捕获率优于95%。由于采用菲涅尔透镜形成矩形光幕,光幕上下的光强分布一致,水平方向光强均匀度达到80%以上,因此系统还可初步区分预制破片速度与尺寸的对应关系。

The deflagration fire lasting for a long time and covering a large area in the process of large equivalent explosion makes it difficult to obtain velocity parameters of fragments in the near-field.In order to solve the problem,it is proposed in this paper aphotoelectric transceiver integrated method which utilize laser screen as the sensing area.The analysis of three different types of warhead explosion flame spectral distribution of radiation shows that 0.3to 1.0μm within the band is at relatively low intensity.On the basis of this,the optical system applies the principle of determining the fixed distance by measuring the time and the reflector technology,which consists of single longitudinal mode laser,cylindrical Fresnel lens,narrow-band filters andhigh-speed optical sensors,etc.The system has its advantage,such as transceiver,compact structure and combination of narrowband filter and single longitudinal mode laser,which can stop the spectrum of fire from suppressing the interference of background light effectively.Large amounts of experiments in different models and equivalent have been conducted to measure the velocity of difference kinds of warheads,obtaining higher signal-to-noise ratio of the waveform signal after a series of signal de-noising and recognition through NI company data acquisition and recording system.The experimental results show that this method can complete the accurately test velocity of fragments around center of the explosion.Specifically,the minimum size of fragments can be measured is 4mm while the speed can be obtained is up to 1 200m·s-1 and the capture rate is better than 95%comparing with test results of target plate.At the same time,the system adopts Fresnel lenses-transparent to form a rectangular screen,which makes the distribution of rectangular light uniform in vertical direction,and the light intensity uniformity in horizontal direction is more than 80%.Consequently,the system can distinguish preliminarily the correspondence between the velocity and the sizes of prefabricated fragments.