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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.

Hearing Protection Devices (HPD), such as earmuffs, are widely used to protect workers from noisy environments. Numerical predictive tools can be used to simulate the vibroacoustic behaviour of earmuffs and thus assess their sound attenuation and improve their acoustical design. The present work describes the implementation of a vibroacoustic finite element numerical model of an earmuff coupled to a rigid baffle in the frequency range from 20Hz to 5000Hz. An experimental assessment of the sound transfer paths through each element of the earmuff (cup, cushion, foam lining) using a specific acoustical test bench is first proposed. This analysis is then used to target the right level of model complexity for each component. An experimental validation of the FEM model is then carried out.

Hearing Protection Devices (HPD), such as earmuffs, are widely used to protect workers from noisy environments. Numerical predictive tools can be used to simulate the vibroacoustic behaviour of earmuffs and thus assess their sound attenuation and improve their acoustical design. The present work describes the implementation of a vibroacoustic finite element numerical model of an earmuff coupled to a rigid baffle in the frequency range from 20Hz to 5000Hz. An experimental assessment of the sound transfer paths through each element of the earmuff (cup, cushion, foam lining) using a specific acoustical test bench is first proposed. This analysis is then used to target the right level of model complexity for each component. An experimental validation of the FEM model is then carried out.