Title: Vibroacoustic Transfer Function Study in the Design of Vehicle Suspensions
text: Noise, vibration and Harshness in the automotive industry became important mainly because the development of modern automobiles and the increased of customer demands for quieter vehicles and with comfortable vibration levels. The sources of vibration and noise inside the vehicle are caused by the engine, tires, transmission systems, suspension, air conditioning, among others. In this work, vibroacoustic transfer function is obtained to analyze the internal noise in two sport utility vehicle with distinctive silhouette. Furthermore, it was analyzed the influence of elastomeric bushings rigidity of the damper in reducing internal noise and vibration and the effect of adding mass in some framework positions for attenuation of vibration peaks due to structural resonance. In the physical tests, it was used accelerometers installed on top of the fixing bracket of the damper and in specific positions in the vehicle body, a microphone installed on the right ear position of the passenger of the right rear seat and an impact hammer used to excite the system to obtain the vibroacoustic transfer function. Temporal measurements are carried out with vehicles on irregular track to a constant speed. The data are processed and analyzed in the frequency domain. The results show that the use of vibroacoustic transfer function is important for understanding and analysis of the noise within the vehicle cabin and that changes in the stiffness of the dampers bushings can reduce noise within the vehicle. Furthermore, the adding of mass to the structure was efficient to attenuate the vibration due to structural resonance.