title: Stable propagation of mechanical signals in soft media using stored elastic energy.
abstract: Soft structures with rationally designed architectures capable of large, nonlinear deformation present opportunities for unprecedented, highly tunable devices and machines. However, the highly dissipative nature of soft materials intrinsically limits or prevents certain functions, such as the propagation of mechanical signals. Here we present an architected soft system composed of elastomeric bistable beam elements connected by elastomeric linear springs. The dissipative nature of the polymer readily damps linear waves, preventing propagation of any mechanical signal beyond a short distance, as expected. However, the unique architecture of the system enables propagation of stable, nonlinear solitary transition waves with constant, controllable velocity and pulse geometry over arbitrary distances. Because the high damping of the material removes all other linear, small-amplitude excitations, the desired pulse propagates with high fidelity and controllability. This phenomenon can be used to control signals, as demonstrated by the design of soft mechanical diodes and logic gates.
authors: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138;
authors: Jordan R
authors: JR
authors: Raney
authors: Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, CA 91125;
authors: Neel
authors: N
authors: Nadkarni
authors: Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125; Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland;
authors: Chiara
authors: C
authors: Daraio
authors: Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, CA 91125; bertoldi@seas.harvard.edu kochmann@caltech.edu jalewis@seas.harvard.edu.
authors: Dennis M
authors: 0000-0002-9112-6615
authors: DM
authors: Kochmann
authors: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138; bertoldi@seas.harvard.edu kochmann@caltech.edu jalewis@seas.harvard.edu.
authors: Jennifer A
authors: JA
authors: Lewis
authors: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138; Kavli Institute, Harvard University, Cambridge, MA 02138 bertoldi@seas.harvard.edu kochmann@caltech.edu jalewis@seas.harvard.edu.
authors: Katia
authors: K
authors: Bertoldi
keywords: instability; mechanical signal; soft; stable propagation