主动Lamb波中的空间滤波器结构健康监测

Direction Filter Method in Active Lamb Wave Structural Health Monitoring

针对主动Lamb波结构健康监测技术在应用中容易受到Lamb波复杂传播特性的影响,监测信号的信噪比较低的问题,提出了空间滤波器方法的基本原理和实现方法,利用压电线阵得到传感信号之间的相干性,实现对有用信号的相干聚焦增强,监测损伤位置并成像,能够实现对特定方向的扫描。分析了空间滤波器的基本原理,给出了用于离散压电线阵的空间滤波器实现形式,并对该方法进行了试验研究,在碳纤维板结构上的试验结果表明,该方法可以有效实现损伤散射信号的聚焦增强,成像突出显示损伤所在方位和位置,提高信号的信噪比,具有一定的工程应用价值。

Active Lamb wave structural health monitoring technology may be influenced easily by the complicated propagation characteristics of Lamb wave in the application.Lamb waves collected have low signal to noise ratio.Research works are carried out to resolve it.Analysis of the direction filter method is proposed in this paper,including the basic principle and implementation method.This method achieves coherent focusing on the useful signal by using the coherence between sensed signals of linear piezoelectric sensor array,monitors and images the damage.At the same time,it can scan the interested direction of the structure.The principle of the direction filter is analyzed.The implementation of the method for the discrete piezoelectric sensor is given.This direction filter method is verified by experiment.In the experimental research on carbon fiber enforced structure,the results show that the method can effectively achieve the focusing and enhancing on damage scattering signal,image and highlight the position and location of damage,and improve signal to noise ratio.