Performance enhancement of piezoelectric smart backing ring (PSBR) considering the effect of installation on the dynamics of vehicle-floating slab track systems

The current research on piezoelectric energy harvesting in the field of rail transport mainly focuses on the structural design of piezoelectric energy harvesters (PEHs). The effect of installation of PEHs on the dynamics of the vehicle-track system has not been fully understood, which, however, is critical for ensuring operational safety due to the additional devices attached to the track structure. On the other hand, these PEHs may have lower performance with improper design parameters without the understanding of the coupled dynamics of the vehicle-track system. In this paper, employing the piezoelectric smart backing ring (PSBR), a dynamic model of the vehicle-floating slab track-energy harvester coupled system is developed to study the effect of installations on its dynamic behavior. In the model, the energy harvester is introduced by only considering its equivalent stiffness. Both single and multiple energy harvesters are considered. The results indicate that when the equivalent stiffness exceeds 1×10 ⁹ N/m, the installation of the harvester has almost no effect on the dynamic performance. Further, with the guidance of the developed model, two kinds of improved designs are proposed based on the piezoelectric tube stacks (PTSs) for performance enhancement. The improved design I is realized by decreasing the cross-sectional area and the number of piezoelectric stacks (PSs), and the improved design II is realized by further increasing the layer number of the PS on the basis of improved design I. The energy harvesting performance (EHP) of two improved designs is tested under both harmonic and steel-spring fulcrum forces, and comparisons are also made with the experimental results of the previous design. The results demonstrate that, in comparison to the previous design, both of the improved designs exhibit enhanced electrical outputs, notably in terms of the open circuit voltage amplitude (OPVA) and maximum average power (MAP) under harmonic force conditions, as well as the voltage peaks, power peaks, root mean square (RMS) power and maximum total energy (MTE) across ten cyclic steel-spring fulcrum force signals. In particular, for the improved design II, the MTE can reach up to about 2.4129 J for ten cyclic signals, marking a significant enhancement of roughly 2.86 times compared to the previous design. The present work provides a valuable guidance for the optimization design and installation of PSBRs.