基于时间反转理论,对主动Lamb波复合材料结构脱层损伤成像监测技术进行了研究。分析了时间反转方法的理论基础以及对波源的信号聚焦过程。根据信号传播自身的特性,研究采用时间反转聚焦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,分析给出了具体的损伤信号时间反转聚焦增强过程;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。在玻璃纤维复合材料板上的真实损伤实验结果表明,该方法能有效提高损伤散射信号的能量,较为准确地监测出损伤的位置、大致范围等特征。
Based on the time reversal theory, the active Lamb wave damage imaging method for composite structural delamination detection was researched. The theory basis of the time reversal process was analyzed, and the focusing process to the source was discussed. Depending on the character of Lamb wave propagation, the damage scattering signals were time reversed and reemitted to the damage, and then they will arrive at the damage synchronously so that the damage scattering signal caught again will be amplified. Details about the time reversal amplifying process were analyzed and given. Based on the focalization ability of time reversal theory to the wave origin, the wave propagation was rebuilt by an image method which displays the damage as the focusing point. Experiments on the glass fiber reinforced composite board indicate that the sensing data energy can be amplified by this method, and the location and range of the damage can be expressed well.