Holographic interferometry applied to characterize the dynamic and modal behavior of in-the-ear hearing aid devices

摘要

Abstract: Holographic Interferometry has been successfullyemployed to characterize the materials and behavior ofdiverse types of structures under stress. Specializedvariations of this technology have also been applied todefine dynamic and vibration related structuralbehavior. Such applications of holographic techniqueoffer some of the most effective methods of modal anddynamic analysis available. The technology isnon-destructive, real-time, and definitive in allowingthe identification of vibrational modes, displacements,and motion geometry. Structures and processed materialscan be analyzed with very low amplitude excitation andthe resultant data can be used to adjust the accuracyof mathematically derived structural models.Holographic Interferometry has offered a powerful toolto aid in the development and analysis of new designsfor in-the-ear hearing aid technology. Engineeringapplications such as this must consider that themicroscopic components and the mounting structures inthese devices are highly susceptible to unwantedacoustic vibration and structure borne noise. Theseundesirable effects are detrimental to both theoperation and overall behavior of this sort of device.The requirement for measurement of small vibration,modal, and mechanical motions are ideal requisites foranalysis using advanced holographic methods in initialdesign and subsequent test. Holographic methods arenon-destructive, real-time, and definitive in allowingthe identification of vibrational modes, displacements,and motion geometries. Such information can be crucialto the determination of mechanical configurations anddesigns as well as operational parameters of in-the-earhearing aid structures.!7