Type de document
Études primaires
Année de publication
2019
Langue
Anglais
Titre de la revue
Acta Acustica united with Acustica
Première page
1258
Dernière page
1268
Résumé
The IEC 60318-4 ear simulator is used to measure the insertion loss (IL) of earplugs in the ear canal of an acoustical test fixture (ATF) and is designed to represent an average acoustic impedance (in a reference plane) of the human ear. The ear simulator is usually modeled using a lumped parameter model (LPM) which has frequency limitations and inadequately accounts for the thermo-viscous effects in the simulator. The simulator numerical models that can better deal with the thermo-viscous phenomena often lack essential geometric details. Most related studies also suffer from the lack of experimental validation of the models. Therefore, a transfer matrix (TM) model of the IEC 60318-4 simulator is proposed based on a direct assessment of its geometric dimensions. Such a model is of particular interest for designing artificial ear simulators. The variability in the simulator impedance due to the geometric uncertainties is quantified using the Monte Carlo method. The TM model is validated using i) a finite element (FE) model of the simulator and ii) impedance measurements with a sound intensity probe. It is found to better describe the simulator impedance above 3 kHz compared to the LPM. The TM model is then coupled to a FE model of an occluded ATF ear canal to simulate the IL of an earplug in the frequency range [100 Hz, 10 kHz]. In the model, the simulator is considered as a cylindrical cavity terminated by an equivalent tympanic impedance which is determined from the TM model to simulate the sound pressure measured at the real microphone position (not at the reference plane) in the ATF ear canal. The simulated IL is validated against i) that obtained with a complete FE model of the corresponding system and ii) measurements using an ATF. The TM model is shown to better agree with the simulator FE model than the LPM above 6 kHz regarding the earplug IL simulated using this method.
Mots-clés
Protection de l'ouïe, Hearing protection, Évaluation du confort, Comfort assessment, Protège-tympan, Earplug, Modèle, Model, Simulation
Numéro de projet IRSST
2017-0032
Citation recommandée
Luan, Y., Sgard, F., Benacchio, S., Nélisse, H. et Doutres, O. (2019). A transfer matrix model of the IEC 60318-4 Ear Simulator: Application to the simulation of earplug insertion loss. Acta Acustica united with Acustica, 105(6), 1258-1268. https://doi.org/10.3813/AAA.919403
Included in
Acoustics, Dynamics, and Controls Commons, Occupational Health and Industrial Hygiene Commons