Optimization-based designs for communicating through impenetrable barriers with mechanical waves

Abstract

Piezoelectric-based acoustic energy transmission is an emerging alternative communication method that allows signal transmission across a barrier without wires or physical penetration. A major challenge in the design of an electrical-mechanical coupled communication channel is how to resolve the undesirable signal transformation known as acoustic multipath as the elastic wave propagates through a multi-layered deformable solid. Solutions largely investigated by the communications community are typically based on sophisticated signal processing methods. However, we approach the problem through the lens of computational mechanics and design optimization. Proposed method is to design a piezoelectric stack that mitigates acoustic multipath by optimizing the thickness of various stack layers and the material properties of the epoxy-based backing. We optimize the design parameters of a 3-D coupled electrical-mechanical finite element model using partial differential equation (PDE) constrained optimization. We leverage higher order polynomial elements (P-elements) and high-performance computing to solve the computationally expensive 3-D wave propagation problem in the MHz frequency range. The results demonstrate how finite element modelling and optimization can be used to achieve optimal physical channel designs for mechanical acoustic-based communication. [SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.]