Analysis of mode conversion and scattering of guided waves at cracks in isotropic beams using a time-domain spectral finite element method

Detecting damages in its early stage, and hence, to ensure the safety and reliability of structures is of vital important. Guided waves have been recognised as one of the promising damage detection techniques that are sensitive to small and different types of damages. The understanding of guided wave propagation and scattering phenomena at the damages is one of the fundamental elements to facilitate the development of this technique for damage characterisation. This paper presents a study of scattering characteristics and mode conversion effects of guided waves at cracks in isotropic beams. An efficient time-domain spectral finite element method using one-dimensional (1D) beam element is developed to solve this problem. The developed model is then used to carry out a series of case studies that consider different crack sizes in the beams. These parametric studies provide a fundamental physical insight into the mode conversion phenomena and scattering characteristics of the guided waves at the cracks.