Abstract

It is well known that the dynamic behaviour of engineering structures may carry very important and crucial information that can be further used for the assessment of their condition as well as detection of any damage induced. The current interest in monitoring techniques based on the propagation of guided elastic waves requires that numerical techniques used for modelling the phenomena associated must shift into the realm of high frequency dynamics in contrast to traditional low frequency dynamic modal analysis. However, high frequency dynamics may present serious difficulties, which may have their origin in the numerical approach used. In that light the aim of the current work is to present certain results obtained by the authors related to two different spectral finite element approaches (frequency-domain and time-domain) for condition monitoring and damage detection of various engineering structures including simple 1-D and 2-D structures as well as complex 3-D structures. Also an effective numerical technique based on the application of an absorbing layer with increasing damping (ALID) for propagation of guided elastic waves in infinite or semi-infinite engineering structures of complex geometries is presented. Its concept has been not only presented by the authors, but certain relations between the layer properties and the characteristics of propagating elastic waves have been given that can help to maximise the layer performance in terms of its damping capability. Beside the assessment of the effectiveness of the numerical techniques used by the authors various numerical issues and problems that can be encountered during numerical simulations and that can strongly influence their accuracy or even determine their existence are discussed and presented.

Authors (4)