碎片云超高速撞击声发射信号特征分析

发布时间：2018-04-26 20:27

本文选题：二次碎片云 + 超高速撞击　；参考：《高压物理学报》2014年06期

【摘要】：为了掌握带防护屏的航天器结构受空间碎片超高速撞击时的声发射信号特征,利用二级轻气炮发射球形弹丸撞击铝合金双层板结构,获取了碎片云撞击铝合金板舱壁产生的声发射信号,并利用小波包技术和能量熵理论对信号进行了分析。实验结果表明:弹丸初始速度、防护屏厚度及弹丸直径是决定二次碎片云形态及声发射信号特征的重要因素;在本实验工况范围内,小波包能量熵值能够描述声发射信号频率的复杂程度;当弹丸初始速度处于破碎段(3~7km/s)时,随着初始速度的增大,二次碎片云进一步细化,撞击产生的声发射信号幅值趋于减小、频率成分趋于复杂化,其小波包能量熵值逐渐增大;防护屏厚度对声发射信号的小波包能量熵值影响较大,弹丸直径对其影响较小。研究结果有助于实现对碎片云撞击舱壁结构的损伤模式识别。
[Abstract]:In order to grasp the characteristics of acoustic emission signals of spacecraft structure with shield when it is impacted by space debris at hypervelocity, a spherical projectile was fired by a two-stage light gas gun to impact the aluminum alloy double-layer plate structure. Acoustic emission signals generated by debris cloud impact on aluminum alloy bulkhead are obtained and analyzed by wavelet packet technique and energy entropy theory. The experimental results show that the initial velocity of the projectile, the thickness of the shield and the diameter of the projectile are the important factors that determine the shape of the secondary debris cloud and the characteristics of the acoustic emission signal. The energy entropy of wavelet packet can describe the complexity of acoustic emission signal frequency. When the initial velocity of projectile is in the broken section of 3km / s, the secondary debris cloud is further refined with the increase of initial velocity, and the amplitude of acoustic emission signal produced by impact tends to decrease. The energy entropy of the wavelet packet increases gradually, and the thickness of the shield has a great effect on the energy entropy of the acoustic emission signal, and the diameter of the projectile has little effect on the energy entropy of the wavelet packet. The results are helpful to identify the damage pattern of debris cloud impact bulkhead structure.
【作者单位】：哈尔滨工业大学空间碎片高速撞击研究中心;
【基金】：国家空间碎片专题研究项目(kjsp06211)
【分类号】：TN911.6

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