一种改进的近邻多损伤“移相叠加”成像方法

Improved "delay-and-sum" imaging method for adjacent multi-damages

近邻多损伤成像是Lamb波成像研究中的一个难点。在传统"移相叠加"方法基础上提出一种改进的近邻多损伤成像方法。为了避免或减轻相邻损伤散射信号间的混叠,该方法利用双面激励产生较高空间分辨率的单模式Lamb波监测信号。同时,根据Lamb波在传播中的能量衰减情况,引入衰减补偿因子来减小监测信号对不同位置监测灵敏度的差异。理论分析和实验均证明了上述两处改进对于提高近邻多损伤成像质量的有效性。

Adjacent multi-damages imaging is a difficult point in the research of Lamb wave imaging. Based on the traditional ＂delay-and-sum＂ method, an improved adjacent multi-damages imaging method was proposed. To avoid or reduce the overlapping between neighboring damage scattered signals, double side excitation was adopted in the method to generate single mode Lamb wave monitoring signals with higher spatial resolution. Meanwhile, according to the energy attenuation in the propagation of Lamb waves, a compensation factor was introduced to reduce the monitoring distinctions of monitoring signals at different locations. Both theoretical analysis and experiment show that the above two improvements can make the imaging results of adjacent multi-damages better.