Regulable energy valves for energy harvesting by screw-nut structures

Abstract Piezoelectric energy harvesting (EH) is very important for environment protection. Here we developed a novel regulable phononic crystals (PnCs) featuring screw-nut structures as an energy valve for EH in wave transmission environment. It is fabricated by additive manufacturing for experimental tests. By regulating the nut of the designed PnCs, the peak output voltage and output electric power of the EH system can be varied in the range of 0.066–2.15 times and 0.004–4.63 times, respectively, compared to the unregulated PnCs. The output performance of the EH system increases as the screw-nut structure is screwed out by guiding the wave transmission, localizing more energy at the defect. The output performance of the EH system significant decrease due to the regulated nut near the defect disrupts the periodicity of the PnCs, preventing the formation of band gap and defect band. Experimental results corroborate the numerical simulations, validating the feasibility of employing screw-nut structures to manipulate output performance. This study offers a regulable solution for adaptive EH systems being capable of responding to varying environmental conditions and energy demands, and provides valuable insights for the design of self-powered devices.