Application and Development Challenges of Dynamic Damper in Cabin Booming Noise Elimination 2014-01-0013
Automotive OEMs quest for vehicle body light weighting, increase in Fuel efficiency along with significant cut in the emissions pose significant challenges. Apart from the effect on vehicle handling, the reduction of vehicle weight also results in additional general requirements for acoustic measures as it is an important aspect that contributes to the comfort and the sound quality image of the vehicle, thus posing a unique challenge to body designers and NVH experts. Due to these conflicting objectives, accurate identification along with knowledge of the transfer paths of vibrations and noise in the vehicle is needed to facilitate measures for booming noise dampening and vehicle structure vibration amplitude. This paper focuses on the application of a unique design and development of vehicle body structure anti-vibration dynamic damper (DD), unique in its aspect in controlling booming noise generated at a specific RPM range.
Design methodology follows the concept of Mass-damper system on vehicle body or engine structure where panel with multi-degree of freedom vibrating at medium level frequency is transferred to damper which is vibrating at same resonant frequency in 180° opposite phase. A method of Design optimization of the damper through Value engineering to cut down cost and weight of the damper is documented and discussed. Part design with consideration to directions of vibration, problem frequency, packaging, manufacturing feasibility, End of life (ELV), is focused upon. As Dampening material stiffness, Tensile strength, compression set and weight of dynamic dead mass are some crucial characteristics, design of experiments was done to identify the affectivity of solutions. Actual cabin noise analysis with pre and post damper addition is presented to corroborate the resonance damping efficacy of the solution proposed. Further the case study showcases the part level and vehicle level tests performed to evaluate the durability during the vehicle endurance. Insight into the strength performance tests with material choices and their relation to performance criteria is put forth.