title: Low frequency finite element models of the acoustical behavior of earmuffs.
abstract: This paper compares different approaches to model the vibroacoustic behavior of earmuffs at low frequency and investigates their accuracy by comparison with objective insertion loss measurements recently carried out by Boyer et al. [(2014). Appl. Acoust. 83, 76-85]. Two models based on the finite element (FE) method where the cushion is either modeled as a spring foundation (SF) or as an equivalent solid (ES), and the well-known lumped parameters model (LPM) are investigated. Modeling results show that: (i) all modeling strategies are in good agreement with measurements, providing that the characterization of the cushion equivalent mechanical properties are performed with great care and as close as possible to in situ loading, boundary, and environmental conditions and that the frequency dependence of the mechanical properties is taken into account, (ii) the LPM is the most simple modeling strategy, but the air volume enclosed by the earmuff must be correctly estimated, which is not as straightforward as it may seem, (iii) similar results are obtained with the SF and the ES FE-models of the cushion, but the SF should be preferred to predict the earmuff acoustic response at low frequency since it requires less parameters and a less complex characterization procedure.
authors.affiliation: Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Boyer
authors.affiliation: Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada.
authors.forename: Olivier
authors.initials: O
authors.lastname: Doutres
authors.affiliation: IRSST, Direction Scientifique, 505 Boulevard de Maisonneuve Ouest, Montréal, Québec H3A 3C2, Canada.
authors.forename: Franck
authors.initials: F
authors.lastname: Sgard
authors.affiliation: Department of Mechanical Engineering, École de technologie supérieure, 1100 rue Notre-Dame Ouest, Montréal, Québec H3C 1K3, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Laville
authors.affiliation: IRSST, Service de la recherche, 505 Boulevard de Maisonneuve Ouest, Montréal, Québec H3A 3C2, Canada.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Boutin
mesh_terms: D000162:Acoustics; D004430:Ear Protective Devices; D004867:Equipment Design; D020342:Finite Element Analysis; D008962:Models, Theoretical; D009038:Motion; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D015203:Reproducibility of Results; D014732:Vibration