Holographic interferometry applied to characterize the dynamic and modalbehavior of in-the-ear hearing aid devices,

摘要

Abstract: Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. The technology is non-destructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometry. Structures and processed materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural models. Holographic Interferometry has offered a powerful tool to aid in the development and analysis of new designs for in-the-ear hearing aid technology. Engineering applications such as this must consider that the microscopic components and the mounting structures in these devices are highly susceptible to unwanted acoustic vibration and structure borne noise. These undesirable effects are detrimental to both the operation and overall behavior of this sort of device. The requirement for measurement of small vibration, modal, and mechanical motions are ideal requisites for analysis using advanced holographic methods in initial design and subsequent test. Holographic methods are non-destructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Such information can be crucial to the determination of mechanical configurations and designs as well as operational parameters of in-the-ear hearing aid structures.!7