基于声发射的单层铝板高速撞击损伤类型识别

Damage Identification of Single Aluminum Plate Produced by Hypervelocity Impact Based Acoustic Emission

针对基于声发射技术的在轨航天器遭受空间碎片撞击损伤的评估问题,采用AUTODYN软件进行了弹丸超高速正撞击铝板所产生声发射波动信号的数值模拟,给出了二维模拟结果;对所得到的声发射信号进行小波重构,得到低频和高频部分的信号。通过研究低频和高频信号的峰值变化,发现第一和第二峰值幅度与撞击速度的变化具有一定的规律性,通过低频第二峰值幅度与第一峰值幅度比值将高速撞击损伤模式分为成坑、锥形穿孔和圆柱形穿孔三种类型。

In order to ensure the astronauts＇ safety and spacecraft normal operation,the design of sensor systems to the detect damage impacts on spacecraft become an important problem of spacecraft design.Numerical simulations of acoustic emission（AE） signals produced by projectile hypervelocity impacting on an Aluminum plate at normal direction are carried out by using the SPH（smoothed particle hydrodynamics） technique of AUTODYN hydro-codes in this paper.The results are given by using two dimensional simulations.In order to separate characteristics of different wave modes,the AE signals are divided into low frequency and high frequency modes by means of wavelet time-frequency transform and reconstruction.The results show that the damage condition of the spacecraft can be represented by the amplitudes of the reconstructed impact signals.The patterns of impact damage can be divided into three types according to the ratio of second to first peak amplitudes of AE reconstructed low frequency signals.