Investigation on Natural Frequency of Different Thicknesses of Cartilage in Myringoplasty

A human middle ear system which includes tympanic membrane and ossicles (three tiny bones) has a function as a mechanical system transmitted sound and vibration from outer through to the inner ear section. Myringoplasty is an operation performed to repair a hole (perforation) in the tympanic membrane (TM). Sliced cartilage is generally used by an otolaryngologist to repair tympanic membrane perforation. The natural frequency for different thicknesses of cartilage in myringoplasty was compared to the normal tympanic membrane to find proper thickness in order to get the best hearing of the human ear system. The purpose of this work is to show the effect of different thicknesses of cartilage in myringoplasty using the Finite Element Method (FEM). The geometrical model of the human middle ear system was generated by the CAD Software using the physical properties of the human middle ear system reported by the previous researcher. Then, Hypermesh was used to create the Finite Element (FE) model. The eigen-value analysis is performed to obtain the mode shape and natural frequency of the human middle ear system with varied thicknesses of cartilage from 0.1 to 10 mm. Thus, by comparing the first natural frequencies of each cartilage thicknesses, we found that the maximum natural frequency of the human ear system when the cartilage’s thickness is 0.13 mm. This disorder is the effect of the human middle ear system’s mass and stiffness.