Research on integrated electrical and mechanical response of piezoelectric asphalt pavement material under bidirectional cyclic loads

In recent years, road vibration capture technology based on the piezoelectric effect has been a research hotspot in the field of road engineering. In tests, although some researchers often use vertical vibration to simulate vehicle load, they ignore the influence of the tangential force of vehicle load on the field road on the power generation performance of the road piezoelectric energy harvester (RPEH). Therefore, this study used a static and dynamic large-scale direct shear instrument to conduct a bidirectional cyclic load test on a piezoelectric-asphalt pavement specimen, and the effects of different vertical vibration and horizontal shear values on the RPEH open-circuit voltage and output power were analysed. Simultaneously, a 3D simulation model of the piezoelectric-asphalt pavement specimen and piezoelectric ceramic sheet were established, and the test results were verified. The experimental and simulation results showed that when vertical vibration or horizontal shear acted alone, the output power of the RPEH increased in proportion to the vertical (load magnitude and frequency) and horizontal (shear frequency and displacement) conditions. The output power remained at an energy level of 10−5 W under vertical vibration, which is three orders of magnitude greater than that of horizontal shear action. However, under the combined action of vertical vibration and horizontal shear, the specimen displayed “dilatancy behaviour”. During vertical vibration (200 kPa, 4 Hz) and horizontal shear (1 Hz, 0.1 mm), the maximum output power of the RPEH was 5.05 × 10−5 W. Thus, this research provides an important reference for the power generation performance prediction of an RPEH under bidirectional cyclic dynamic loads.