3D High-Speed Digital Image Correlation (3D-HSDIC) to Study Damage of Human Eardrum Under High-Pressure Loading

Abstract

High-intensity impulsive sounds (e.g., explosions, firearms, etc.) are known to damage the human eardrum (Tympanic Membrane, TM), and produce conductive hearing loss. However, the eardrum failure mechanism under high-pressure loading has not been well studied. Our previous investigations have shown the feasibility of using full-field-of-view 3D High-Speed Digital Image Correlation (3D-HSDIC) with a custom-made loading apparatus to study acoustically induced damage on artificial membranes. In this paper, we present new measurements on multiple human post-mortem eardrums. The dynamic 3D displacements and transient shape changes of the entire eardrum surface during the rupture are simultaneously quantified at high frame rates (i.e., >100,000 Hz) using the 3D-HSDIC method over the rapid time-course of the TM response. The results describe the high strain-rate and large displacements of the eardrum from the initial stages of rapid pressurization up to complete eardrum failure. The high spatio-temporal resolution measurements allow the determination of eardrum mechanical properties under high-pressure loading. This study indicates the potential utility of high-speed DIC to study high pressure induced TM failure mechanisms, which has impact on developing new hearing protection devices. Future measurements will be performed with a miniaturized optical system and an updated high-pressure loading apparatus designed using advanced thermo-acousto-fluidic numerical modeling and high-speed Schlieren imaging techniques.