| The process of acquiring the ambient vibrating energy and converting it into usable electrical energy using piezoelectric materials is termed piezoelectric power harvesting. It has seen a dramatic rise in the area of power harvesting in rencent years because of its simple theoretical foundation, environment friendliness and high energy conversion efficiency. However, related research on this technique mainly focuses on power supplying for microelectromechanic system, little study is available on large electric energy generation using piezoelectric materials, and even almost blank in domestic. In view of these facts, large scale piezoelectric energy harvesting is investigated against the background of civil engineering in this disertation, with main contents organized as follows:(1) The mode of electromechanical convertion of piezoelectric materials and the theoretical model of 1-3 piezoelectric composites are analysed; and the relationship between voltage and material property under surface load for 1-3 cement-based piezoelectric composites is investigated.(2) PZT-5H ceramic fibers are fabricated by viscous polymer processing (VPP). Sintering condition of PZT fibers is determined by DSC curve and ceramic bodies'sintering temperature, and then PZT fibers are fired using Muffle H.T electric furnace at this condition.(3) The dependence of piezoelectric strain constant of PZT fibers on poling conditions is studied. The results show that for PZT fibers, the optimum poling electric field E, poling time t and poling temperature T are 2.5kv/mm, 45min and 90°C, respectively.(4) By arranging PZT fibers and casting reactive powder concrete (RPC), 1-3 cement-based piezoelectric composites are fabricated with self-made RPC and PZT fibers as matrix and functional part respectively. Theoretical model is established for energy harvesting by 1-3 cement-based piezoelectric composites prepared above, and the energy harvesting effect is also studied theoretically and experimentally. |
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