Acoustic wave focusing by doubly curved origami-inspired arrays

Spherically focused transducers have been long relied on to target acoustic energy delivery. Yet, these structures have limitations with respect to size and mobility for medical treatment applications. Recent developments in the field of reconfigurable structures reveal that the ancient art of origami inspires new platforms by which to enable spherical shapes that are additionally foldable for ease of transport. This research explores the opportunities for a unique, flat foldable doubly curved tessellated array to enable wave focusing capability similar to an ideal medical transducer shape: the spherical cap transducer. An analytical model of the doubly curved array is created and validated against data collected from a proof-of-concept array. The model is then leveraged to understand how the array design and complexity relatively govern the wave focusing capability. The findings show that doubly curved acoustic arrays do not require excessive facet refinement to achieve wave focusing similar to nominal spherically focused transducers. Yet, the optimal frequencies for which such capability is borne out vary substantially on the basis of array design. The discoveries of this research motivate future consideration of flat foldable doubly curved acoustic arrays for potential implementation into medical transducer development for hard-to-access surgical treatments.