Properties Of Fractal Piezoelectric Vibrator Based On Sierpinski Triangle

The mechanical energy, such as vibration of an automobile engine, the air disturbance caused by the aircraft flying, the beating of the human’s heart,can be everywhere in our environment. This is typical vibration energy which is less affected by the environment. At present, the technology of collecting and using the vibration energy is gradually rising. And it is very significantly meaningful to replace the use of the chemical batterys with vibration transducers. However, the traditional vibration transducers have low power density and narrow bandwidth. In order to solve these technical problems, this paper according to the idea of fractal structure, and use various fractal piezoelectric oscillators to broaden the bandwidth of energy acquisition.In this paper, a broadband piezoelectric oscillator structure based on Sierpinski triangle fractal is designed. This structure is based on fractal, piezoelectric theory and cantilever beam. It is turned into cantilever beams and filled according to the characteristics of Sierpinski triangle, to ensure the utilization of the materials and the diversity of the structure. A fractal structure of piezoelectric vibrator with self-similarity at three levels is designed, to ensure the piezoelectric oscillator at least has three different resonant frequencies. So it can broaden the bandwidth of energy acquisition and collect different frequencies of mechanical energy in the environment. And afer filling, the number of each level is increased effectively, can improve the energy density and output voltage.In this paper, the finite element calculation is used to study the frequency and output voltage characteristics of the fractal piezoelectric oscillator. The frequency of each level and the whole fractal piezoelectric oscillator are calculated, and explore the strain and output voltage changes with frequency by sweeping frequency. The simulation results show that the fractal piezoelectric oscillator can broaden the spectrum width, increase the energy harvesting density and the output voltage with increasing fractal level.The fractal piezoelectric oscillator is processed and packaged with PVDF according to the design. An experimental platform is set up, and the sweep frequency response experiment is consistent with expectations. So in this paper, the design of fractal piezoelectric oscillator can remedy narrow bandwidth defect and low energy density defect which both exist in the current vibration transducers.