Bilinear Nonliearity of Bio-inspired Adaptive Diaphragm structure

초록

This study presents the initial assessment for a new shaped bio-inspired adaptive diaphragm structure aimed at mimicking the function of the tympanic membrane (TM) of human auditory systems. The TM consists of three parts: malleus, pars tensa, and pars flaccida, and the dynamic behavior of the TM is typically known to be different from other common thin membranes. It has a curved conical shape, with the apex pointing medially, and an initially bucked shape. The malleus is also firmly attached to the medial surface of the membrane at its center. In addition, the TM is connected to a surrounding annulus ligament (muscle) and is concave at the deepest part (the umbo). As a result, the TM does not move as a normal flat and thin diaphragm. In this study, we investigated the bilinear nonlinearity of elliptic and conical shaped diaphragm similar to actual TM of human auditory system to deliver improved vibrating characteristics. We report that the proposed adaptive diaphragm structure made by 3-D printing technology can exhibits the bilinear nonlinearity when the sound pressure level (SPL) of incoming sound is high, resulting in the improved sensitivity and broad frequency response.