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Inverse Vibration Problem Used for the Characterization of the Damping Added by a Trim Foam on a Plate
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 30, 2020 by SAE International in United States
Event: 11th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference
Many solutions exist to insure the NVH comfort of ground and air vehicles, like heavy mass (bitumen pads), viscoelastic treatments and absorbing foams. The trim foam is an alternative to heavy solutions. To know the potential of the foam, a study of its capacity to damp vibration is done. A system, composed by a suspended plate, with a foam on it, is characterized in different cases of contact at the foam-plate interface (glued or not) and with different types of foam. An experimental test facility is developed to identify the global damping of the structure: a laser vibrometer measures the displacement field of the foam-plate structure, an inverse method is used to determine the structural parameters. By changing the contact at the interface, it is possible to identify the contribution of the friction forces to the global damping of the structure. Another type of damping is the viscoelastic damping due to the intrinsic characteristics of the trim foam. With the help of FEA, it is possible to understand the influence of the damping effect. The implemented inverse methods are the Force Analysis Technique (FAT) and the Corrected Force Analysis Technique (CFAT), originally used for effort identification on a system. They are based on the motion equation of the system and the displacement field. Here, these methods determine the structural parameters, such as the elastic storage modulus and the loss factor.