Numerical modelling techniques to optimise automotive-type panels for reduced sound radiation

Numerical predictions are becoming ever more important in automotive development when analysing the Noise, Vibration and Harshness (NVH) performances of vehicles. In the low- to midfrequency range, vibro-acoustic predictions are generally performed using the finite element method (FEM) and/or boundary element method (BEM). In this paper, a numerical optimisation technique is described that aims at reducing the sound radiation from automotive-type panels over the frequency range of interest. The objective function, i.e. the radiated acoustic power, is calculated with a quadratic equation in terms of surface velocities. The genetic algorithm (GA) based optimisation aims to minimise the value of the objective function by modifying the normaldirection (Z-direction in an X-Y plane) of a few nodes of the finite element model of the panel, thereby imposing a geometrical change in the panel. The equation of an ellipsoid is used to smooth out the discontinuity after the change in the nodal coordinates and, hence, dome-shaped indentations are obtained. The resulting panel designs are analysed, both numerically and experimentally to support the approach presented.

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CC BY-NC-ND 4.0