A nonlinear finite-element model of the newborn ear canal.

A three-dimensional nonlinear finite-element model of a 22-day-old newborn ear canal is presented. The geometry is based on a clinical x-ray CT scan. A nonlinear hyperelastic constitutive law is applied to model large deformations. The Young's modulus of the soft tissue is found to have a significant effect on the ear-canal volume change, which ranges from approximately 27% to 75% over the static-pressure range of +/-3kPa. The effects of Poisson's ratio and of the ratio C10: C01 in the hyperelastic model are found to be small. The volume changes do not reach a plateau at high pressures, which implies that the newborn ear-canal wall would not be rigid in tympanometric measurements. The displacements and volume changes calculated from the model are compared with available experimental data.