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Tactile feel of vehicle touch points and boom feel inside vehicle cabin are some of the important criteria of the customer choice while making the buying decisions in the dealership or on a test drive. This tactile and acoustic feel of a vehicle is majorly governed by the low frequency mode management achieved while designing the vehicle. Different parameters like inclusion of multiple powertrains on a vehicle program, choice of multiple way seating different at driver’s, front passenger’s and rear passengers’ seating positions, instrument panel and steering system layouts having higher torque delivery, suspension modes of the front and rear axles based on their articulation and degree of independency, global modes of the vehicle body, the cabin air cavity configuration and volume, etc. play a significant role in deciding this tactile and acoustic feel of the vehicle being designed.

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 recent years, car manufacturers have been working intensively on new ways to improve the quality of interior trims. Elimination of squeak and rattle has become one of the main concerns for car manufacturers lately, given the significance of these incidences in customers' perception of overall quality. Traditionally, rattle problems are found and fixed with physical tests at the late design stage, mainly due to lack of up-front CAE simulation prediction methodology and tools availability. This article presents a finite element based methodology for the improvement of rattle performance of a vehicle tailgate. In this study, appropriate finite element (FE) modeling technique was introduced to accurately predict occurrence of tailgate rattle. Simulation process using commercial software “Nastran” employing modal and forced frequency response analyses was illustrated. Design modifications were incorporated for performance improvement of rattling on present and future SUVs.

Achieving targeted global modes (torsion, vertical bending and lateral bending) is one of the main enablers in meeting desired NVH performance characteristics of a new vehicle program. The torsion mode of next generation Land Rover - Freelander was lagging behind its target while the development cycle was quite progressed beyond underbody freeze. There was a challenge to recover more than 8 Hz in BIW torsion mode. A combination of Nastran Sol 200 (design sensitivity and optimization) and iterative process was adopted to demonstrate how the mode could be recovered with optimum mass penalty to the program. The paper states the existing modal status when this work was taken up. Next it elucidates design sensitivity/optimization module outcome which identifies sensitive areas to improve torsion mode.