A numerical method for the simulation of NDT experiments in an elastic waveguide

Abstract

This work concerns the numerical simulation of a non destructive testing experiment in an elastic waveguide. The transient wave which is produced by the transducer is represented, in the frequency domain, as a superposition of modes. As a consequence of Auld’s reciprocity principle, the echo measured by the receiver can be expressed by a formula combining the modal amplitudes and the scattering matrix of the defect. An original and efficient finite element formulation has been developed for the computation of this matrix, which applies to arbitrary flaws: the unknowns are the displacement field in a small portion of the waveguide containing the defect and the normal component of the normal stresses on the artificial boundaries. Numerical results are presented in the two-dimensional case.