High-fidelity 3D modeling of tonotopic responses in the human cochlea via acoustic-fluid-structure interaction

• A 3D cochlear model was developed with realistic spiral and material properties. • Acoustic-fluid-structure interactions were simulated from 100 Hz to 17 kHz. • Standing waves at low and traveling waves at high frequencies were identified. • Limitations in prior cochlear models lacking full AFSI coupling were addressed. • Broader insights into auditory disorders are expected through extended modeling. Hearing loss remains a major global health concern, demanding more precise modeling of cochlear mechanics to enhance diagnostic and therapeutic strategies. Although previous research has explored cochlear function, many existing models fail to capture the complex, coupled interactions between acoustic waves, cochlear fluids, and the basilar membrane's dynamic response. In this study, we develop a high-fidelity three-dimensional numerical model incorporating realistic spiral cochlear geometry, anisotropic material properties, and detailed acoustic-fluid-structure interaction (AFSI) mechanisms. The model simulates pressure distributions, vibrational displacements, and stress fields across a frequency range of 100 Hz to 17 kHz. Results reveal that low-frequency stimulation produces standing wave patterns with uniform displacement amplitudes, whereas mid-to-high frequencies generate traveling waves consistent with the cochlea’s tonotopic organization. Displacement amplitudes on the basilar membrane range from approximately 0.5 μm at low frequencies to 2.5 μm at high frequencies, while von Mises stress levels vary from 1 μPa at the apex to 10 Pa near the base. The peak vibration locations shift progressively from the apex toward the base as frequency increases. This validated computational framework offers detailed insights into cochlear biomechanics. It holds potential for optimizing hearing aid and cochlear implant designs, advancing inner ear therapies, and guiding future research into auditory pathophysiology.