Quantifying Real-Time Dynamic Responses and Damage Mechanics of Human Tympanic Membranes Exposed to Blast Waves.

Understanding the tympanic membrane's (TM, or eardrum) response to high-intensity acoustical events, such as blasts, is crucial for preventing and treating blast-induced auditory injuries. Despite its importance, there remains a gap in methodologies and measurements of the TMs rapid dynamic responses to these events. This study investigates the behavior of human TMs exposed to blasts using a novel system that integrates high-speed quantitative imaging techniques with a custom shock tube (ST). High-speed three-dimensional-digital image correlation (DIC) and high-speed Schlieren imaging techniques are applied in synchronization with high-frequency pressure sensors to quantify generation and propagation of shock wave (SW) and its interaction with the TM during the tests. Additionally, digital microscopy and optical coherence tomography (OCT) are utilized to characterize the TM's morphology pre- and postblast exposure. The full-field high-speed dynamic responses of cadaveric human TMs and their fluid-solid interactions with different levels of blast overpressures are presented, and the rupture of the TMs is described in real-time. These measurements are employed to assess whether the TM behaves as a thin shell under exposure to high acoustical events. The findings from these studies enhance the comprehension of the TMs biomechanics and damage mechanics under harsh conditions, thereby advancing prevention and treatment strategies for blast-induced auditory damage.