超高速撞击声发射信号在加筋壁板中传播的模态转换现象研究

Hypervelocity impact induced AE wave mode conversion in a plate with vertical stiffeners

为应对空间碎片对载人密封舱的撞击威胁,一种基于声发射的在轨感知系统被应用于载人密封舱,通过采集撞击产生的声发射信号,感知撞击事件并定位由此产生的气体泄漏源或潜在泄漏源。载人密封舱舱壁通常由周期性加筋板焊接而成,声发射信号在筋体处会发生复杂的散射现象。针对散射现象中的模态转换现象,采用数值仿真手段,研究了超高速撞击声发射信号所含各模态板波在筋体处的模态转换特性,结果表明:S0、A0、S2阶板波经过筋体后会分别部分转换为A0、S0、A1阶板波;A1阶板波经过筋体后会部分转换为S0阶板波。

To respond to impacting threats from orbital debris,an onboard monitoring system based on acoustic emission （AE）technique was used in a manned pressurized cabin to detect impact events by collecting hypervelocity AE signals propagating in its module wall.Usually the module wall was made by welding integral stiffened shell structures, AE signals cross stiffeners during propagation and cause reflection,transmission and mode conversion.Here,numerical simulation was adopted to study the mode conversion characteristics of AE signals.The results indicated that after passing through a stiffener,parts of S0,A0,S2 wave modes are converted into A0,S0,A1,respectively;A1 wave mode is partially converted into S0 wave mode.