Speakers

Keynote Speakers

Prof. Yigui Li, Shanghai Institute of Technology

李以贵教授，上海应用技术大学

Experience: Yigui Li, professor, PhD supervisor, Tohoku University, Japan. He is mainly engaged in the research and teaching of micro-electromechanical system (MEMS), micro-sensor and micro-actuator. Successively presided over 16 national, provincial and ministerial projects. He has published more than 100 research papers in academic journals at home and abroad, including more than 30 SCI papers and more than 70 EI papers. We have applied for 52 national invention patents, of which 31 have been authorized. Currently, he is an evaluation expert of degree and postgraduate education of the Ministry of Education. Evaluation expert of Science and Technology Evaluation Center of Ministry of Science and Technology; National Natural Science Foundation of China; Senior member of China Micro-nano Association; Reviewer of "Acta Optica Sinica", "Chinese Physics Letter", "Chinese Laser", "Optics and Precision Engineering", "Sensor Technology" and other magazines.

Title: Research on hollow piezoelectric energy harvester with cantilever beam structure based on bulk PZT

Abstract: In this thesis, aiming at the problems of low power density and low applicability of cantilever beam piezoelectric energy harvester, a patterned hollow cantilever beam piezoelectric energy harvester based on block PZT is designed and fabricated. The main research contents of this thesis are as follows:1.Taking the stainless steel-based piezoelectric energy harvester as an example, the effects of different Young's modulus and density of the substrate on the natural frequency and voltage output of the device were respectively studied. It is proposed to replace stainless steel with flexible brass as the substrate, and a graphical hollow simulation model is designed. The stress distribution and charge density distribution of the elastic layer of the cantilever beam under resonance conditions are calculated by finite element simulation. The simulation calculation shows that the trapezoidal hollow piezoelectric energy harvester has the best performance. Compared with the unhollowed brass-based device, its maximum stress extends from the clamping end to 4400 μm, and the average stress increases by 71.4%. The average charge density is improved by 5.6 times.2.The preparation of the energy harvester is completed through the multi-layer composite processing technology. The high-voltage coefficient PZT is used as the piezoelectric layer, the low-modulus brass is used as the substrate, and the stainless steel-based piezoelectric energy harvester is set as the sample group. The process conditions of different substrates are explored; the device prototype is fabricated by vacuum thermocompression bonding, screen printing and laser welding. Piezoelectric energy harvesters with triangular, rectangular and trapezoidal holes are obtained by laser etching technology.3. The stress distribution and charge density distribution of the elastic layer of the cantilever beam of the piezoelectric energy harvester with each hollow structure are obtained by finite element simulation, and the superior performance of the device with hollow holes is verified by experimental tests. The results show that the hollow design can greatly improve the overall stress level and power density of the device. The proposed trapezoidal hollow-out piezoelectric energy harvester exhibits the best performance, with peak voltage and power density of 17V and 2.52mW/cm3, respectively, at acceleration, resonant frequency, and matched load of 0.5g, 56.3Hz, and 114kΩ, respectively. Compared with the non-hollowed device, the peak voltage and maximum power density are increased by 30.7% and 24.4%, respectively, and the resonant frequency is decreased by 7%. Simulation and experiments verify that increasing stress distribution can be an important indicator for improving device performance.