Cochlear mechanics, engineering acoustics and active structures are fields of research where intense and exciting work is underway. In this research proposal, the three seemingly disparate areas are brought together. The performance of mammalian hearing combines remarkable transient capture and frequency filtering, with a dynamic range that can encompass at least a million-fold change in energy. The mechanical, fluid dynamical and electrical functions of the cochlea are largely responsible for these specifications, specifications which are unparalleled in man-made mechanical systems. While the current state of understanding of the function of the cochlea is incomplete, this research seeks to take advantage of the known structure-function relations of this evolutionary design for engineering acoustics. For applications ranging from sound quieting to sound sensing, the cochlear analogue design holds great potential for improving frequency selectivity and sensitivity. One such application centers on utilizing the structural acoustic filtering of the cochlea for sound attenuation, i.e., as a quieting mechanism, to augment and even replace widely used silencers (such as mufflers). A cochlear-based microphone and hydrophone transducer is also studied. Advanced modeling of the unsteady fluid-structure interaction problem is undertaken to provide design tools and to understand phenomena. Various realizations of designs for hydraulic and air borne acoustic systems are modeled, built and tested. The success of this line of research will significantly change the sound quieting (e.g., muffler) and transducer (e.g., microphone) industries. In addition, better understanding of cochlear analogues will provide a better understanding of hearing processes themselves.
The educational portion of this grant seeks to (1) integrate modern software including computational, analytic and graphical packages into the classroom setting and (2) increase industrial relevance by introducing case studies to classroom, stemming from both industry sponsored research projects and industry contributed case studies.
