Numerical determination of modal dispersion and AE signal characterization in waveguides through LBIE/BEM and time–frequency analysis

摘要

In the present paper a meshless local boundary integral equation (LBIE) method is employed for the numerical determination of dispersion curves in plate like waveguides. Next, the LBIE method is properly combined with the boundary element method (BEM) for the characterization of acoustic emission signals derived from nucleating surface-breaking and body cracks in plate-like waveguides being in contact with a fluid. The time history of the propagating guided waves is computed by means of either the LBIE method or the hybrid LBIE/BEM scheme and the representation of mode dispersion is accomplished through the Reassigned Smoothed Pseudo Wigner–Ville time–frequency analysis. The effectiveness of the method is demonstrated through representative numerical examples.