Damage spectral element for condition assessment of one-dimensional waveguides

The stress waves generated with piezoelectric actuators can propagate along a path defined by the material boundaries of a structure. If there are damages or discontinuities in the path, the received wave will be greatly affected. The changes of the waveform can provide enormous characteristics which will indicate the conditions of damage in the structure. Based on this theory, the guided wave (GW)-based methods are developed to detect local damages in a structure. In order to investigate wave propagation in damaged waveguides, many numerical modelling methods have been developed. Among them, spectral element method (SEM) solves the governing partial differential equation of wave propagation problem in the frequency domain using fast Fourier transformation (FFT). It is not only efficient for computation but also accurate for analysis in comparison with the conventional finite element formulation. In this paper, a damage spectral element is developed to model local discontinuity by using reflection and transmission coefficients. Numerical simulations show that the method is efficient to simulate local damage in one-dimensional waveguides.