ISMA2016 location:Leuven date:19-21 September 2016
The aim of this paper is to investigate the possibility to detect defects in pipes based on wave-scattering in the audible frequency range. Therefore, the influence of a 1cm long defect extending in axial direction and a defect extending over a 12° angle in circumferential direction on the wave scattering in a DN80 steel pipe is investigated. At first the reflection and transmission of different incident wavemodes at these defects is studied using a hybrid wave and finite element/finite element formulation. To investigate the effect of finite dimensions, in a next step, FE calculations are performed on finite pipes, which are harmonically excited with a 0-order wavemode with dominant radial or longitudinal displacement, respectively. It is found that the wave scattering at the defect happens according to the scattering matrix prediction based on the hybrid WFEM/FEM method. Furthermore, the wave scattering can be magnified due to the resonance behavior of a finite structure, so that it gives a dominant contribution to the overall displacement, even though the scattering coefficient might be small.