Harnessing the bilinear nonlinearity of a 3D printed biomimetic diaphragm for acoustic sensor applications

Abstract

Abstract This study presents an initial assessment of a newly shaped biomimetic diaphragm aimed at mimicking the function of the tympanic membrane (TM) of the human auditory system. The TM consists of three parts, namely, the malleus, pars tensa, and pars flaccida, and its dynamic behavior is typically known to be different from other common, thin membranes. The constructed membrane has a curved conical shape with the apex pointing medially, and with 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 its 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 an elliptic and conical shaped diaphragm similar to the actual TM of the human auditory system to deliver improved vibrating characteristics. It is reported that the proposed adaptively diaphragm structure fabricated by using 3D printing technology can exhibit bilinear nonlinearity when the sound pressure level (SPL) of the incoming sound is high, thus resulting in a flat sensitivity and a broad frequency response.