DAMAGE LOCALIZATION OF SIMPLY-SUPPORTED BEAM UNDER MOVING FORCE

Dynamic displacement response of a beam subjected to moving force consists of two components, namely "moving-frequency component" of the moving force and 'natural-frequency component' of the beam. This paper aims to investigate the effects of local damage on these two different components and develop a corresponding damage localization method. Based on modal perturbation and modal superposition methods, an algorithm for obtaining the closed-form solution of dynamic response of a damaged simply-supported beam under moving force is proposed firstly. With this algorithm, damage induced changes in the moving and natural- frequency components are examined thoroughly, and the former is found to be preferred for damage localization. Then multi-scale discrete wavelet transform (DWT) is adopted to extract the moving frequency component from the total dynamic response to locate damage. Numerical examples are simulated to demonstrate the effectiveness of the proposed response calculation algorithm and the corresponding damage localization method.