Modular design, fabrication, and experimental exploration of phononic chains incorporating interchangeable, nonlinear unit cells

We present a modular framework for the streamlined design, fabrication, and experimental exploration of phononic chains composed of interchangeable unit cells. Increased interest in periodic media motivates experimental set-ups for exploring reconfigurable lattice designs with variable couplings. We employ additive manufacturing as a means to rapidly assemble lattices interfaced by unit cells in a reconfigurable and modular manner. Additive manufacturing produces lightweight spring-like structures while boasting batch printing capabilities. Batch printing reduces production time and increases uniformity in the lattice by reducing the number of joints. The framework reported herein allows for either linear or nonlinear unit cells to be inserted at interface locations. We discuss two example nonlinear unit cells and explore their effects on wave transmission through an otherwise uniform monatomic lattice. One nonlinear cell blocks low amplitude wave packets but transmits high amplitude signals, whereas the second nonlinear cell yields the opposite effect. These cells may inspire devices such as noise filters and limiters based on signal amplitude. The modular framework also enables serial combinations of lattices and cell types that individually integrate frequency filtering, amplitude filtering, and directional control. By combining unit cells with different filtering effects, it is possible to produce combination filters with multifunctional capability - e.g., simultaneous frequency and amplitude filtering.