Virtual and experimental physical comfort testers for earplugs

Earplugs are commonly used to prevent noise-induced hearing loss, but their efficacy is often hindered by discomfort, impacting consistent and correct use. Comfort of earplugs can be comprehended through four dimensions: physical (related to biomechanical and thermal interactions with the earcanal), acoustical (linked to noise perception), functional (including usability and efficiency) and psychological (related to well-being and satisfaction). The evaluation of (dis)comfort involves intricate interactions among components of a triad formed by the user, the earplug, and the work environment. Recent research by the authors has identified key psychosocial and physical characteristics of the triad influencing earplug physical discomfort. This study examines specific physical characteristics of the coupling between the "user" and "earplug" components for disposable and reusable earplugs. Virtual and experimental comfort testers serve as modeling tools and test benches to enable this determination. Mechanical comfort testers of increased complexity designed to assess tribological characteristics of the earplug/earcanal system are introduced. The study starts with simple benches measuring radial forces, extraction forces and friction coefficients, progressing to more advanced tools assessing mechanical pressure in various earcanal shapes either with rigid walls or lined with skin. This work aims at providing earplugs comfort-driven design methods for manufacturers.