title: Axisymmetric versus three-dimensional finite element models for predicting the attenuation of earplugs in rigid walled ear canals.
abstract: The axisymmetric hypothesis of the earplug-ear canal system geometry is commonly used. The validity of this hypothesis is investigated numerically in the case of a simplified configuration where the system is embedded in a rigid baffle and for fixed boundary conditions on the earplug lateral walls. This investigation is discussed for both individual and averaged insertion loss predictions of molded silicon earplugs. The insertion losses of 15 earplug-ear canal systems with realistic geometries are calculated using three-dimensional (3D) finite element models and compared with the insertion losses provided by two-dimensional equivalent axisymmetric finite element models using 6 different geometry reconstruction methods [all the models are solved using COMSOL Multiphysics (COMSOL, Sweden)]. These methods are then compared in order to find the most reliable ones in terms of insertion loss predictions in this simplified configuration. Two methods have emerged: The usage of a variable cross section (with the same area values as the 3D case) or the usage of a constant cross section (with the same length and volume as the 3D case).
authors: Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec, H3C 1K3, Canada.
authors: Guilhem
authors: G
authors: Viallet
authors: IRSST, Direction Scientifique, 505 Boulevard de Maisonneuve Ouest, Montréal, Québec, H3A 3C2, Canada.
authors: Franck
authors: F
authors: Sgard
authors: Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec, H3C 1K3, Canada.
authors: Frédéric
authors: F
authors: Laville
authors: IRSST, Service de la Recherche, 505 Boulevard de Maisonneuve Ouest, Montréal, Québec, H3A 3C2, Canada.
authors: Jérôme
authors: J
authors: Boutin
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004424:Ear Canal / Q000033:anatomy & histology* / Q000502:physiology*; D004430:Ear Protective Devices; D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D008953:Models, Anatomic; D008954:Models, Biological; D009622:Noise / Q000517:prevention & control*; D009716:Numerical Analysis, Computer-Assisted; D015203:Reproducibility of Results; D012828:Silicones
chemical_list: D012828:Silicones