Sensitivity Study of Different Damping Treatments Using Simulation and Physical Testing Methodologies on Structure Borne Driver’s Ear Noise Performance in a Premium Hatchback Car

Effective damping treatment of the BIW panels of a vehicle is one of the important NVH enablers to attenuate in-cab structure borne noise and panel vibrations. Adding these damping treatments using physical testing methods at a later stage in a vehicle development program may lead to sub-optimal configuration, mass and cost of these treatments. To counter this, a validated simulation based approach to determine damping treatments must be deployed much upfront in a vehicle development program. Effectiveness of a damping treatment depends on identification of most appropriate application locations on the BIW panels of a vehicle being designed and at the same time on employing most appropriate materials having desired properties for these treatments.

For identifying optimized locations of damping treatments in the development of a new Tata car program, simulation based composite modal strain energy method and physical test based sound intensity mapping technique were deployed. In earlier stages of development, much before the physical prototypes of the car were available, the damping treatment locations and appropriate materials were proposed using simulation methodology. Effectiveness of these identified locations was established through simulating body attachment point noise transfer functions (NTFs). Final damping locations were arrived at based on comprehensive study of these simulation results. Subsequently, sensitivities of different damping treatment materials available in market were studied to arrive at the most effective application of these damping treatments. Once the physical prototypes were built later in the program, these identified locations were validated through physical testing using sound intensity mapping method. The results correlated well with the simulation. Appropriate conclusions based on this study were made.