HYBRID FE/WFE APPROACH FOR THE COMPUTATION OF THE SCATTERING PROPERTIES OF JOINTS

The analysis of automotive vehicle body noise and vibration requires the use of verified modeling and computational tools which would be applicable in the whole audio-frequency range (20 Hz - 20 kHz). The wave and finite element (WFE) method is proposed to bridge the mid-frequency gap by extending the applicability range of the finite element (FE) method. In this work the numerical method for linking vehicle sub-components, such as welded and bonded panels, and describing the transfer of structure-borne sound across these interfaces is presented. The scattering of waves in such joined plates is analysed with the help of the hybrid FE/WFE approach. The WFE method is used to characterise the wave propagation in flat and curved panels that are homogenous in two directions by analysing the FE model of, typically, a rectangular segment of the panel. The joint is modelled using standard FE with a matching number of nodes at the interfaces with the panels. Then, continuity and equilibrium conditions are enforced at the interfaces. Coupling the WFE and FE models can be utilised to deduce the scattering of waves through the joint. In particular the flow of power will be investigated at different frequencies and in various incidence directions. The method enjoys the advantage that the FE model can be obtained using standard FE libraries and /in-house packages. The presented approach can be further used in the context of conducting a Dynamical Energy Analysis (DEA) of a built-up structure in the context of ray dynamics, which requires the knowledge of the scattering properties of the joint. The method relies on the analysis of small FE models and only a small segment of the joint is modelled; thus, the present approach can be used to develop optimal constructions in various applications.