| Generally，the pressure on both sides of the tympanic membrane is just balance,butsometimes，because of some special reasons the pressure on both sides of the tympanicmembrane is not equality and it engender a pressure which is working at the tympanicmembrane and brought about great change in the middle ear sound transmission．In thisthesis, the effects of ear canal pressure on middle ear sound transmission is studied by usingfinite element method, mainly done the following research：Firstly, according to the CT section images of human temporal bones of the no hearingimpairment history, through image processing software and CAD software we access to themiddle ear geometry, and through the finite element analysis software Hypermesh gridacquired middle ear3D finite element model, verified and corrected repeatedly the finiteelement model with the domestic and foreign research results.Basing on the relatively perfect finite element model, In order to determine materialparameters of the middle-ear soft tissues as the stress-dependent elastic modulus relative tothe ear-canal air pressure, the empirical formulas were fit out to calculate the equivalentelastic modulus of the middle ear components based on the FE analysis and experimentaldata of middle ear response in the literature. By changing the material parameters of themiddle ear soft tissue, the influence of ear-canal static pressure on the mobility of themiddle ear was stimulated, and the changes of cochlear input, including the stapesdisplacement and the differential pressure between the oval window and round window, were obtained.The results show that：he effect of the ear canal pressure on middle ear soundtransmission is slightly greater than the effect of positive pressure,the effect of ear-canalstatic pressure on the differential pressure between the oval and round window is slightlygreater than the effect of stapes displacement in the low frequency range．This studyprovide the basis for the establishment of middle ear stock room map．... |
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