Accurate Replication of an Ear Pinnae Geometry for Use in Acoustic Testing of Spatial Cues and Sound Localization
Additive manufacturing (AM) enables freedom of design as well as fabrication of complex objects such as the human ear. In medical modeling there is a need for patient-specific customizable parts. The outer human ear consists of these main parts: the pinna, which naturally filters sound, and the ear canal, which is the point at which sound enters before being moved up to the tympanic membrane, otherwise known as the eardrum. In an attempt to accurately replicate ear models, the use of scanning and reverse engineering methods was used. A comparison of 3D laser scanning systems was performed to determine their use in medical model scanning applications. A computer-aided design (CAD) model and a standard tessellation language (STL) file of a standard pinna were generated using CT and 3D laser scanning. Multiple 3D printing technologies (desktop and industrial) were used to fabricate test samples of the generated models. These models were then compared in terms of material selection, printer capability, and acoustic performance. Applications in hearing protection devices were also explored. A CAD model of a hearing protection device integrated with the standard pinna to filter the incoming sound was designed, 3D printed, and subjected to acoustic testing. After evaluating scanning methods, CT scanning remained the most accurate, and some 3D laser scanning systems are more favorable than others. Printing and testing of 3D ear models was successful and showed similarities in acoustic testing compared to original ear models. Some printing technologies performed better than others. All were successful in replicating ear models. Results from this work will hopefully lead to improved hearing aids and hearing protection devices with applications on the battlefield, in emergency response situations, and providing improved experiences for children with sensitive hearing.
Biomedical engineering|Acoustics|Medical imaging|Materials science|Audiology
Belmont, Alejandra, "Accurate Replication of an Ear Pinnae Geometry for Use in Acoustic Testing of Spatial Cues and Sound Localization" (2020). ETD Collection for University of Texas, El Paso. AAI28263526.