D. Žižys “Investigation and optimization of autonomous energy sources operating in higher transverse vibration modes” doctoral thesis defence

Author, Institution: Darius Žižys, Kaunas University of Technology,

Science area, field of science: Technological Sciences, Mechanical Engineering – 09T

Scientific supervisor: Prof. Dr. Rimvydas Gaidys (Kaunas University of Technology, Technological Sciences, Mechanical Engineering, 09T).

Dissertation Defence Board of Mechanical Engineering Science Field:
Prof., Dr. Habil. Minvydas Ragulskis (Kaunas University of Technology, Technological Sciences, Mechanical Engineering, 09T) – chairman
Assoc. Prof., Dr. Eric Courteille (National Institute of Applied Sciences, France, Technological Sciences, Mechanical Engineering, 09T),
Prof., Dr. Vytautas Jūrėnas (Kaunas University of Technology, Technological Sciences, Mechanical Engineering, 09T),
Prof., Dr. Habil. Rimantas Kačianauskas (Vilnius Gediminas Technical University, Technological Sciences, Mechanical Engineering, 09T ).

The doctoral dissertation is available at the libraries of Kaunas University of Technology (K. Donelaičio str. 20, Kaunas) and Aleksandras Stulginskis University (Studentų g. 11, Akademija, Kauno raj.).

Annotation:
The aim of this research is to analyze and develop different piezoelectric vibration energy harvester power output maximization techniques taking advantage of higher vibration modes and ensuring its operation at varying mechanical excitation conditions. The object of investigation is nonlinear piezoelectric vibration energy harvester operating in dynamic/vibro-impact contact conditions at higher vibration modes. The problem of increasing efficiency of such a harvester is addressed.
Efficiency of a generator operating in higher transverse vibration modes was increased using developed and verified calculation methodology which allows to optimally harvest the energy generated by it, avoiding energy losses due to charge cancelation. Efficiency of a generator operating in vibro-impacting mode was increased by identifying optimal dynamic and electrical parameters of frequency-up converting piezoelectric vibration energy harvester operating under highly nonlinear dynamic contact vibro-impact excitation. For this purpose, mathematical and computational models of nonlinear dynamic contact of piezoelectric vibration energy harvesting elements was created. Mathematical optimization methods were used.
During the work, specific finite element models and calculation methodologies were created that can be used for very relevant and advanced investigation of vibro-impact contact process dynamic in piezoelectric vibration energy harvesters and determining harvester’s optimal parameters, which enables cost reduction of experimental and theoretical investigations.