Finite Element Model of a Piezo-Electric Actuator Coupled to the Middle Ear

The hearing contact lens® (HCL) is a new type of hearing aid devices. One of its main components is a piezo-electric actuator. In order to evaluate and maximize the HCL's performance, a model of the HCL coupled to a middle-ear model was developed using finite element approach. The model was validated step by step starting with the HCL only. To validate the HCL model, vibrational measurements on the HCL were performed using a laser-doppler-vibrometer (LDV). Then, a silicone cap was placed onto the HCL to provide an interface between the HCL and the tympanic membrane of the middle-ear model, and additional LDV measurements on temporal bones were performed to validate the coupled model that was used to evaluate the equivalent sound pressure of the HCL. Moreover, a de-eper insight was gained into the contact between the HCL and tympanic membrane and its effects on the HCL performance. The model can be used to investigate the sensitivity of geometrical and material parameters with respect to performance measures of the HCL and evaluate the feedback behavior.