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.