Abstract:

The fundamentals of the modal density was introduced, and a semiempirical formula calculating the modal density when the surface curvature changes was deduced. A statistical energy analysis(SEA) model was built for a certain domestic car, and the modal densities of the simplified car subsystems were calculated. The modal density of each subsystem was also calculated with the finite element analysis(FEA) method. Both results were compared each other. The 1/3 octave band spectrums of the car interior driver earvicinity noise were predicted at speed 100 km/h by both the subsystem modal density calculation and the FEA calculation. Both results were compared with the test results. The effects of calculation precision of the subsystem modal density on the precision of car interior noise prediction were discussed. The results indicate that the car interior noise prediction precision by the SEA model can be improved effectively by enhancing the modal density calculation precision of the car subsystems, the predicted error of the car interior noise can be kept within 1 dB(A). The model results satisfy the requirement on car interior medium and highfrequency noise prediction at the car development phase, providing a reference for the car acoustic design.

Key words: vehicle engineering, car interior noise, statistical energy analysis(SEA), modal density, noise prediction