Analysis Of The Vibration Attenuation Effectiveness Of Free Layer Damping And Dynamic Vibration Absorber Under Mass Constraint

As the environmental protection and fuel consumption problems become more and more critical, reducing the power consumption and emission through light weight design has become a popular trend in modern automobile design. However, light weight design by reducing the structure thickness or using light-weight alternative materials is often accompanied with the tendency of weakening structural dynamic stiffness, which is a challenge to improve the noise, vibration and harshness (NVH) performance. Seeking light weight vibration and noise approaches that are suitable for vehicle applications thus becomes an important question faced by the automotive industry. As two effective vibration and noise control approaches, damping layer and dynamic vibration absorber (DVA) have been extensively used in vehicle structures..Based on the simply supported beam and plate theory, one primary purpose of this study is to investigate and compare the vibration effectiveness of the free layer damping (ULD) and the dynamic vibration absorber (DVA) approaches under the mass constraint. For the case of the simply supported beam, build on the foundation of the theoretical and experimental results presented in Ref. [1], the vibration response models of attaching ULD and DVAs to the simply supported beam are developed first in this study. Then the genetic algorithm (GA) is used to optimize DVA’s parameters that are applied to control the beam vibration response. The beam response with the optimized DVA parameters is compared to that of the beam with the ULD treatment, which in turn shows the effectiveness of both methods under the mass constraint. Similarly, the vibration control effectiveness when applying the optimized DVA and ULD to a simply supported panel is also compared both analytically and experimentally. It is demonstrated that, with the constraint of same mass addition to the primary structure, DVA approach is more effective than the ULD approach in controlling the low frequency vibration. Furthermore, with properly optimized parameters, the DVA approach presents better overall control effectiveness in a broadband sense.