复合材料胶接损伤的指数监测方法

为了监测复合材料胶接损伤,基于主动Lamb波和时频分析,提出了一种复合材料损伤监测的指数法。通过对Lamb波信号进行时频分析,提取波形包络。通过计算得到损伤散射信号,选取对损伤敏感的直达波波包,将此波包在结构出现损伤后的能量变化值与损伤前的能量之比作为损伤指示。该方法不用选择特定的Lamb波模式,解决了Lamb波在复合材料结构中存在的频散、多模式及模式转换给信号分析带来的困难。同时在复合材料胶接的损伤演化试验中,对该方法进行了应用验证研究。结果表明:该方法可以用于复合材料胶接损伤的定性和定量分析。

An Index Method of Monitoring Composite Debonding

In order to monitor composite debonding,an index method is proposed to monitor the damage of composites by using the active Lamb wave and time-frequency analysis.The envelope of the time varying signal is picked up according to the time-frequency analysis of the Lamb wave,and the direct wavepacket which is sensitive to damage is selected after obtaining and evaluating scattered signals.Then the ratio of the wavepacket energy variation because of damage to the baseline wavepacket energy is defined as the damage index.This index method does not need to select a special Lamb wave mode and is helpful in overcoming the problems of signal analysis with multi-modes and mode conversion of the Lamb wave.Monitored by this method,two damage evolving tests of composite debonding are carried out.The results show that this method can be applied to qualitative and quantitative analysis for composite debonding.