Solving Airborne and Structureborne Noise Issues Using Modal Analysis

Most of NVH related issues start from the vibration of structures where often the structure vibrates at resonance and radiates the energy in terms of sound. A modal analysis of a structure not only provides the dynamic response of the structure in terms of mode shapes and the extent of vibration, but it also has the potential to aid in tuning and shifting the mode shapes of the structure and thereby has the potential to reduce noise, provided the right visco-elastic materials with appropriate damping properties are used. This paper discusses a case study where a panel used on an agricultural machine cab was studied for both airborne and structureborne noise radiation purposes. The paper also discusses that the selection and use of visco-elastic materials with proper damping properties was able to shift the mode shapes of the panel which resulted in an increase in sound transmission loss and eventually resulted in reduced sound level in the cabin interior.