Determining Vibro-Acoustic Characteristics and Structural Damping of an Elastic Monolithic Panel 2019-01-1538

Evaluations of the dynamic and acoustic responses of panels, partitions, and walls are of concern across many industries, from building home appliances, planning meeting rooms, to designing airplanes and passenger cars. Over the past few decades, search efforts for developing new methodologies and technologies to enable NVH engineers to acquire and correlate dynamically the relationship between input excitations and vibro-acoustic responses of arbitrary-shaped panels has grown exponentially. The application of a particular methodology or technology to the evaluation of a specific structure depends intimately on the goals and objectives of the NVH engineers and industries. In this work, we present the comparisons between the traditional modal analyses for structural vibrations together with sound intensity measurements of sound radiation and a laser-assisted Helmholtz equation least squares (HELS) method [1, 2, 3, 4] to characterize the dynamic and acoustic responses of an arbitrarily shaped structure subject to non-contact acoustic excitations. Input data for the latter include the normal surface velocities measured at a finite number of points on the surface of the structure that are accessible to a laser beam, and the acoustic pressures measured at a few points in the near field. With these input data, we will be able to reconstruct the normal surface velocity, the surface acoustic pressure, the normal surface acoustic intensity distributions over the entire structure, dimensionless structural damping ratio spectrum, sound transmission losses (STL), and sound transmission paths, etc. These data enable engineers to acquire a comprehensive understanding of the vibro-acoustic characteristics of any arbitrarily shaped vibrating structure, which can lead to the most cost-effective NVH reduction.