主动Lamb波结构健康监测中信号增强与损伤成像方法

Amplifying Signal and Imaging Damage Method for Active Lamb Wave Structure Health Monitoring

主动Lamb波结构健康监测技术研究中,损伤散射信号的信噪比是正确稳定地监测出损伤的关键。针对真实工程结构,尤其是针对复合材料板结构健康监测时存在的信号信噪比低下问题,提出了基于时间反转聚焦原理的信号增强与损伤成像方法。根据Lamb波信号传播自身的特性,通过聚焦的方法使损伤散射信号能量叠加放大,从而提高信号的信噪比;利用时间反转法对波源的自适应聚焦能力,重建信号传播波动图,通过信号聚焦显示损伤位置和区域。在碳纤维复合材料板上的实验结果表明,该方法能有效提高有用信号的能量,较为准确地监测出损伤的位置、范围等特征。

In active Lamb wave structure health monitoring（SHM）, the signal-to-noise（STN） of the damage scattering signal is the key factor in the accurate and stable monitoring.To solve the low STN problem in the real structure＇s SHM,especially in composite SHM,an amplifying signal and imaging damage method based on the time reversal theory is purposed.By the character of Lamb wave propagation,the damage scattering signals are time reversed and remitted to the damage,and then they will arrive at the damage synchronously so that the damage scattering signal caught again will be amplified.Based on the focalization ability to the wave origin of time reversal theory,the wave propagation image is rebuilt to display the damage.Experiments on the carbon fiber reinforced composite board indicate that the sensing data energy can be amplified by this method,and the location and the range of the damage can be expressed well.