超高速撞击声发射信号在Whipple结构中的传播时序特性研究

为研究屏/舱声发射信号传播时序特性，以典型Whipple防护结构为例，利用二级轻气炮对其进行超高速撞击实验。首先，利用独立于靶件的“遮挡板”阻挡弹丸击穿前板形成的二次碎片云撞击后板，利用布置在前、后板特定位置的超声换能器采集单纯的前板声发射信号，分析信号模态特征，结果表明：前板信号主要包括S0、A0和S2等三种模态板波，经圆柱支撑构件传播进入后板之后，全部转换为A0模态板波。在此基础上，建立了屏/舱声发射信号到达时序预测公式。其次，撤除遮挡板，利用布置在后板特定位置的超声换能器采集前、后板信号的混叠信号，分析两种信号的到达时序并与预测结果进行对比，结果验证了达时序预测公式的有效性。

Analysis of the Propagation Sequence Characteristic of Hypervelocity Impact Induced Acoustic Emission Waveform in Whipple Shielding Structure

To study the propagation sequence characteristic of hypervelocity impact induced acoustic emission (AE) waveform in Whipple shielding structure, impact tests against dual-wall structure are performed by using a two-stage light gas gun. A baffle panel is placed between the front/back panel of the dual-wall structure to prevent the debris cloud from impacting the back panel, AE signal induced by projectile impacting front panel is recorded by sensors in both front and back panel, the modal characteristics of the recorded signals are analyzed, the results suggest that AE signals in front panel are composed of A0, S0 and S2 modal waves, they are converted into A0 wave after propagated into the back panel. Based on the result, a prediction formula for arrival time interval between signals from the front and back panel is established. Then the baffle panel is removed, the coupling waveform of the AE signal induced by projectile impacting front panel and the AE signal induced by debris cloud impacting back panel are recorded by sensors in back panel, and the sequence characteristics of the two different signals are analyzed and compared with the formula predictions. The results prove the validity of the prediction formula.