Wavelet based Method for Remote Monitoring of Structural Health by Analysing the Nonlinearity in Dynamic Response of Damaged Structures Caused by the Crack-Breathing Phenomenon

Abstract

In this paper, a new method for remote crack monitoring, based on the crack-breathing phenomenon, is proposed. During vibration, edges of a crack come into and out of contact which causes non-linear effects in the response of a structure. This is caused by the change in the structural stiffness when the crack opens and closes. Wavelet Transform is applied to detect such nonlinear effects in the response signals of the structure. The existence and depth of the crack are determined by using large values (peaks) in the wavelet transform and modulus maxima lines of wavelet transform. The location of the crack is estimated by signal ratios between points along the structure. The results of numerical studies obtained from the FE analysis and experimental tests of simple specimens are in good agreement. The results of further numerical study of a real suspension arm based on the proposed system also promise a practical technique for remote monitoring of complex structures in practice.