Folding star-shaped acoustic transducers for real-time guidance of radiated acoustic waves

Directed acoustic energy is used throughout medical practices, scientific research, and engineering applications. Conventionally, arrays of transducer constituents are assembled and driven with inputs that are determined by digital signal processing methods, which guides the acoustic waves for signal transmission and reception purposes. Beamforming is the term for this approach, although inherent limitations of stability and computational efficiency hinder the outcomes. Recent efforts have revealed the broad merits of folding origami-inspired acoustic array architectures so that the transducer constituent and array shapes change, giving rise to direct control of acoustic energy radiation characteristics. Because the design of the origami tessellation used to create the array is pivotal to the adaptive acoustic energy steering, a new star-shaped foldable transducer is studied in this work for its unique inward and outward shape change characteristics. In order to facilitate this investigation, an analytical framework is developed to identify the connections between the folding-induced topology and radiated sound field. The high-fidelity boundary element method verifies the analytical model while experimental efforts validate the theoretical predictions. The adaptation of radiated sound pressure from the star-shaped transducer is shown to be several orders of magnitude, which illustrates its great potential in acoustic energy guidance and prospective applications.