Estimating a Viscous Damping Model for a Vibrating Panel in contact with an Acoustic Trim Enhanced with Particle Dampers. 2024-01-2917

Dampers (PDs) are passive devices employed in vibration and noise control applications. They consist of a cavity filled with particles that, when fixed to a vibrating structure, dissipate vibrational energy through friction and collisions among the particles. These devices have been extensively documented in the literature and find widespread use in reducing vibrations in structural machinery components subjected to significant dynamic loads during operation. However, their application in reducing vehicle interior sound has received, up to now, relatively little attention. Previous work by the authors has proven the effectiveness of particle dampers in mitigating vibrations in vehicle body panels, achieving a notable reduction in structure-borne noise within the vehicle cabin with an additional weight comparable to or even lower than that of bituminous damping treatments traditionally used for this purpose. This effect may be obtained also by integrating PDs into the B-side of NVH trim parts, so they come into contact with the body panels of the vehicle, providing the desired additional damping. This integration enhances the traditional performance of NVH trim parts, primarily based on their sound insulation and absorption characteristics, by adding also a vibration damping function that may avoid the use of traditional bituminous dampers. Research carried out so far relied mainly on experimental trials and analyses. However, an effective integration of PDs into the design process of a vehicle and/or of NVH trim parts calls for a reliable and efficient procedure to simulate the effect they have on the vibration of vehicle body panels. The development of such a simulation procedure is not straightforward, given the non-linear behavior of PDs. This paper is concerned with this latter topic. In a first part, the paper describes the development of a tool for the characterization of PDs by means of which it is possible to evaluate their Damping Loss Factor (DLF) and Effective Mass (EM). After this, a procedure to include the effect of PDs into Finite Element models of vibrating structures is also described and applied to simplified structures such as beams and plates.