Non-uniform crack identification in plate-like structures using wavelet 2D modal curvature under noisy conditions

Non-uniform crack identification in plate-like structures is of significance in mechanical, aerospace, and civil engineering. The 2D modal curvature is often utilized to identify damage in plates, but its capability to precisely characterize non-uniform cracks has not been resolved well, largely due to two noticeable deficiencies, lack of sensitivity to cracks and susceptibility to noise interference. With this concern, this study formulates the wavelet 2D modal curvatures by ameliorating the 2D modal curvature using the real and complex wavelet transform, respectively. Crack-caused singular peaks appear in crack locations can designate the presence and locations of cracks. Superior to the 2D modal curvature, the real-wavelet 2D modal curvature and complex-wavelet 2D modal curvature enjoy the multiscale analysis capability introduced by the wavelet transform, whereby noise interference can be eliminated. Moreover, the complex-wavelet 2D modal curvature is capable of synchronously eliminating noise and characterizing cracks, which endows it with the capability to identify and characterize non-uniform cracks under noisy conditions. The capability of the complex-wavelet 2D modal curvature is analytically and experimentally validated on plates with non-uniform cracks; its applicability is further explored in a numerical scenario of a plate-like sluice gate with non-uniform cracks. The results show the complex-wavelet 2D modal curvature can characterize the length, extent, and non-uniformity of non-uniform cracks, providing an appropriate tool for identifying and characterizing such cracks in plate-like structures under noisy conditions. (C) 2019 Published by Elsevier Ltd.