Thermally Drawn Piezoelectric Fibers Impart Acoustic Functionality to Fabrics

Abstract

Acoustic interactions with fabrics have predominantly focused on their application as sound absorbers. However, the broader spectrum of fabric-acoustics interactions remains relatively unexplored. This thesis investigates how the relationship between fabrics and acoustics can be leveraged through the use of a piezoelectric fiber. This acoustic fiber can be incorporated into traditional fabrics to transform them into microphones and loudspeakers. Various experiments and simulations are devised to understand how fabric properties influence fabric vibrations. Once the fundamental working mechanisms are understood, fabric systems are engineered to optimize the performance of these acoustic fabrics for various applications.

The acoustic fiber is the key technology that enables this work, as fibers are the building blocks of fabrics. Thermal drawing allows for the scalable production of multimaterial fibers with complex architectures, providing functionality. The processing methods are investigated in detail to reliably create fibers with high piezoelectric performance. The fiber can then be woven into textiles while the fabric's structural identity is maintained. As part of the fabric, the fiber transforms traditional textile materials into microphones or loudspeakers with significant sensitivity and efficiency. The vibrations in the fabrics, whether sensed or generated by the fiber, are measured and visualized, providing a deeper understanding of how nanometer- and micron-scale vibrations result from or give rise to audible sound. Several applications offer glimpses of novel possibilities enabled by acoustic fabric systems, including sound direction detection, biometric sensing, and noise control.