Coupled dynamic and piezoelectric response of RPEHs embedded in road under traffic load via multiscale finite element models

Abstract Road Piezoelectric Energy Harvesting Systems (RPEHs) effectively collect and convert mechanical energy from road surface into electrical energy for intelligent traffic guidance and monitoring. To accurately evaluate the energy harvesting efficiency of RPEHs under traffic loads and road conditions, a multiscale finite element model of traffic load-road-RPEHs is developed. The model encompasses a encapsulated stacked piezoelectric transducer embedded in an large-scale road model. This approach addresses the limitations of previous studies that neglected the effect of RPEHs structure on the dynamic and piezoelectric response. The large-scale model provides the dynamic response of RPEHs for an independent small-scale model of the stacked piezoelectric transducer to enable coupled dynamic and piezoelectric behavior. Furthermore, a piezoelectric output theory considering the loss impedance is formulated. Combining this theory with the open-circuit voltage obtained from the multiscale models, we determine the output voltage and power of RPEHs under various conditions, such as vehicle speeds, axle weights, burial depths. The results demonstrate that the loss impedance undergoes significant changes under different conditions, exerting a substantial impact on the output of RPEHs, which should be considered during analysis. RPEHs positioned closer to the road surface produce higher output but also exhibit increased stress concentration. The pavement modulus is inversely proportional to the piezoelectric output, while the subgrade modulus has a comparatively smaller impact due to the stiffness of RPEHs.