Preparation Of BZT-BCT Piezoelectric Materials And Their Application In Vibration Control And Energy Harvesting

Unwanted sustained vibrations caused by dynamic vibration may results in the fatigue and failure of structures during the period of service, it's important to realize the harvesting and dissipation of vibrational energy to reduce the damage. The active/passive vibration control systems based on piezoelectric materials make the best of the unique mechanical/electrical conversion characteristics and can realize the monitoring of dynamic changes in the structure and feedback to implement vibration control, the mechanical energy can be consumed directly in the process of electromechanical conversion at the same time. High-performance lead-free piezoelectric material Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (abbreviated as BZT-xBCT) can exhibit an excellent piezoelectric constant d33 about 620 pC/N. Nanogenerator using electrospining fibers and 0-3 piezo-damping composites are prepared around the 0.5BZT-0.5BCT material as the core under the concept of environment protection. The piezoelectric composites composed by flexible 0.5BZT-0.5BCT fibers can achieve a large deformation and adapt to dynamic impact better, meanwhile via the output of electric signals the stress/strain can be measured and realize the reduction vibrating independent of temperature, location and other conditions, their output performance and damping properties are well studied. The main research contents include:(1) The synthesis of orientational 0.5BZT-0.5BCT nanofibers via electrospining technique combined with sol-gel method and heat treatment process are studied. The piezoelectric, ferroelectric properties and internal spontaneous polarization are discussed through piezoresponse force microscopy (PFM) test.(2) The relationship between structure and output performance of nanogenerators based on directional aligned 0.5BZT-0.5BCT nanofibers are researched. Nanogenerators with different electrode position are prepared and the output voltage, current, power are tested under different deformation condition, the influence mechanism of the device structure on the mechanical/electrical energy conversion efficiency are discussed.(3) Mechanism of mechanical energy dissipation of 0-3 type piezo-damping composites are studied. 0.5BZT-0.5BCT nano powders are fabricated and added into epoxy resin with acetylene black powders, and synthesized a series of piezo-damping composites through solution blending. The effects of different contents of BZT-0.5BCT, frequency and loading force on damping properties were investigated. A mathematical model was established to understand the piezoelectric damping mechanism in the composites.