路用叠堆式压电单元设计及性能分析

Design and performance analysis of stacked piezoelectric units for pavement application

为提升路用压电单元的俘能效率和工作性能,设计并制作5种路用叠堆式压电单元结构。采用室内试验分析结构参数、负载阻抗和荷载特征对单元压电性能的影响,探究单元结构在极限受压和重复荷载作用下压电性能衰减的规律。研究结果表明:并联式结构能够有效降低单元开路电压,提供稳定的输出电压;开路电压与压电圆片厚度正相关但与堆叠片数无关;相同外径下圆片式单元的开路电压比圆环式高33.5%,具备更好的电学性能;输出功率随负载电阻增大呈先增大后减小的单峰特征,并且在915 kΩ阻值下产生11.0 mW的最大输出功率,表现出最佳的机电转换性能;开路电压随着荷载幅值增加近似线性增加,但随荷载频率增大小幅度减小;开路电压在3.0 kN与5 Hz荷载工况下达到240 V。压电性能衰减测试证明,所制备的压电单元结构满足高应力、多轴载作用的路用要求。

In order to improve the energy harvesting efficiency and working performance of piezoelectric transducers for roadway applications,five stacked piezoelectric unit structures were designed and fabricated.The electrical properties of piezoelectric units with different structural parameters,resistance and traffic loads were studied by laboratory tests,and so was the attenuation law of piezoelectric properties under ultimate compression and cyclic loadings.The results show that open-circuit voltage can be effectively reduced and stabilized by parallel-connected mode,and is positively correlated with the thickness and independent of the number of the piezoelectric wafers.Besides,the open-circuit voltage of a disk-shaped unit is 33.5%higher than that of a ringshaped unit with the same outer diameter,which shows a better electrical performance.The output power shows a single-peak characteristic that increases first and then decreases with the resistance increase.Furthermore,the maximum output power is 11.0 mW with 915 kΩ,which presents a high electromechanical conversion performance.Besides,the open-circuit voltage increases approximately linearly with the load amplitude increase but decreases slightly with the load frequency increases.Specifically,the open-circuit voltage reaches 240 V under the load conditions of 3.0 kN and 5 Hz.In addition,the electrical performance testing shows that the proposed piezoelectric unit structure meets the requirements of high stress and cyclic loadings.