Variable stiffness triboelectric nano-generator to harvest high-speed railway bridge’s vibration energy

Abstract

The integration of vibrating structure and novel energy harvesters is highly desirable for the conversion of vibration energy to electricity. In this paper, a variable stiffness triboelectric nano-generator (VSTENG) composed of a variable stiffness part (VSP) and multiple sets of triboelectric nano-generators (TENGs) is proposed to harvest vibration energy of high-speed railway bridge for meeting the electrical energy requirements of sensor nodes. The working principle of VSTENG is introduced, and the theoretical models of VSP’s force-displacement and TENG’s electrical energy output are derived. The numerical model for the VSTENG is presented and a detailed finite element model for the train-track-bridge system is also established. Then by simulating the running train on the bridge, the vibration responses and corresponding frequency spectrum of the track-bridge structure are analyzed, and the effect of VSTENG’s design parameters is discussed. The results show that the developed energy harvester can enlarge the displacement response and vibrate in a wide-frequency domain inducing partial nonlinearity. Moreover, the shake table tests are conducted, and the effect of design parameters and load resistance are analyzed. The test has shown that the device gets the maximum value of electrical energy output while adopting the track plate response as an input. As the load resistance increases, the electrical energy output would be further increased and then decreases sharply. The TENGs can effectively utilize the amplified displacement and wide-range vibration caused by the VSP and promotes the energy harvesting capacity.