Analysis and identification of multiple-cracked beam subjected to moving harmonic load

Abstract

An exact expression is obtained in the frequency domain for the response of a multiple-cracked beam subjected to a moving harmonic load. The obtained solution is used first for response analysis of the beam in dependence on the load speed, frequency, and crack parameters. Then, based on the solution a procedure is developed for detecting multiple cracks in a beam from the measured frequency response. The most important advantage of the spectral approach is that it allows not only vibration analysis of beam with arbitrary number of cracks under harmonic moving load but also enables to detect an unknown amount of cracks by a sparse grid of measurement sensors. Moreover, the speed and frequency of moving load are useful control parameters for improving either measurements of the frequency response or detecting cracks by using the frequency response. The theoretical development has been illustrated and validated by numerical examples.