Detection of crack location and size in structures using wavelet finite element methods

A methodology to detect crack location and size is presented which takes advantage of wavelet finite element methods (WFEM) in the modal analysis for singularity problems like a cracked beam. First, the beam is discretized into a set of wavelet finite elements, and then the natural frequencies of the beam with various crack locations and sizes are accurately obtained. The frequency response functions, function of crack location and size, are approximated by means of surface-fitting techniques. Measured natural frequencies are used in a crack detection process and the crack location and size can be identified by finding the point of intersection of three frequency contour lines. The experimental data from a free-free beam studied by Silva are employed to verify the accuracy of the method. The present method is general and can be easily extended to complex structures with multiple cracks.