SEA Models To Predict Structureborne Noise In Vehicles

Statistical energy analysis models are often used to predict vehicle noise. These models are generally successful at high frequencies, above 500 Hz, where transmission of airborne noise from the vehicle exterior to the interior is the dominant source of noise. At mid-and low frequencies the noise transmitted by structureborne paths becomes more important. SEA models can be extended to study both airborne and structureborne noise transmission in this frequency range. The modeling is more complex, however, because of the variety of structural wave types and the spatial irregularity of structural parameters. This paper presents the techniques required to develop SEA models for predicting structureborne noise in vehicles. Particular attention is given to the calculation of modal densities and coupling factors in the mid-frequency range from 100 to 500 Hz. Attention is also given to the calculation of the statistical variance of the SEA prediction. Inclusion of the variance prediction allows SEA models to be used over a broad range of frequencies.