基于多维阵列和空间滤波器的损伤无波速成像定位方法

随着复合材料在航空结构中的广泛应用，基于压电传感器（PZTs）阵列和Lamb波的结构健康监测成像方法已经成为复合材料结构健康监测技术的研究热点，但是复合材料的各向异性特点导致依赖于信号传播速度的延迟-累加、相控阵等成像方法难以实现其损伤的准确监测。鉴于此，研究了一种与信号传播速度无关的空间滤波器损伤成像定位方法，该方法利用Lamb波在结构中传播时的空间-波数域特征，通过设置空间权重函数使压电传感器阵列形成波数带宽为[k_min，k_max]的空间-波数域滤波器对特定空间方位的Lamb波进行滤波，得到损伤的角度图像； 然后，利用多维线性压电传感器阵列各自针对损伤得到的角度图像进行融合，得到损伤的坐标图像，从而实现了在不依赖传播速度的情况下对损伤的成像定位。在碳纤维层合板上对该方法进行了实验验证。实验结果表明：基于多维线性压电传感器阵列和空间-波数域滤波算法的无波速成像定位方法可以对复合材料结构损伤进行不依赖信号传播速度的成像定位，定位误差在1 cm以内。

Damage imaging and localization method based on multi-dimension arrays and spatial filter without wave velocity

With the widely application of composite materials in aircraft structures, the structural health monitoring imaging method has become a hot topic in composite structural health monitoring technology research, which is based on the piezoelectric sensors (PZTs) array and Lamb wave. However, the composites' anisotropic makes it difficult to achieve accurate monitoring, which depends on the signal propagation velocity, such as delay-accumulation, phased array and so on. In this paper, the spatial filter damage imaging and location method were studied, which isn't dependent on the signal propagation velocity. The feature of spatial-wavenumber domain was used in this method when Lamb propagation in structures. After setting the space weight function, the PZTs array would be formed a spatial-wavenumber filter with the bandwidth is [k_min, k_max], which can filter a specific space range of Lamb wave and imagine the damage angle. And then, the damage angle images from each of the multi-dimensional PZTs array were integrated, that would give the damage coordinate image. In result, the damage imaging and localization was accomplished without wave velocity. This method was verified on carbon fiber laminates. The verification shows that the method presented is able to locate the composite structures' damage, and the error of localization is less than 1 cm.