Modal Expansion of Experimental Vibration Data for Numerical Acoustic Radiation Prediction

The prediction of the acoustic radiation of vibrating structures is traditionally based on the acoustic boundary element method. This approach leads to good predictions, provided that the dynamic behavior of the system is well known. This paper presents the integration of experimental vibration analysis with numerical acoustic radiation prediction. The developed methodology involves several steps: (i) measure the accelerations on the surface of a vibrating body, (ii) expand these experimental data onto a numerical model, using the modal information of a finite element model, and (iii) run a boundary element analysis to determine the acoustic radiated field.

This procedure presents the advantages that the dynamic behavior is as accurately as possible defined and that the boundary element approach opens wide results interpretation (contribution and sensitivity analysis…). A real-life application example (car engine) is shown to illustrate and validate the developed methodology.