Optimization of a SDOF Cantilever Beam Piezoelectric Energy Harvester with a Lump Mass at the End Tip

Abstract

With the development of low power electronics and energy harvesting technology, selfpowered systems have become a research hotspot over the last decade. The main advantage of selfpowered systems is that they require minimum maintenance which makes them to be deployed in large scale or previously inaccessible locations. Therefore, the target of energy harvesting is to power autonomous ‘fit and forget’ electronic system over their lifetime. Some possible alternative energy sources include photonic energy, thermal energy and mechanical energy. The source of mechanical energy can be a vibrating structure, a moving human body or air water flow induced vibration. The primary objective of this project was the quantification of the vibration spectrum of an AC fan machine, using an accelerometer to provide the amplitude for the frequency of the machine. The frequency (hz) and magnitude (m/s2 ) of the signal was obtained using Fast Fourier Transform analysis from Matlab Signal Processing Tool (SPTOOL).[1] The secondary objective was to analyze a Measurement Specialties MiniSense 100 Vibration Sensor modeled as a single degree of freedom, SDOF, base excited unimorph piezoelectric film energy harvester using a basic cantilevered beam with mass at the tip configuration to calculate the maximum power output produced by the system and tuned the proposed design to reached a maximum power generation. The same analysis was performed on the data from the cantilever sensor and the frequency of vibrations was obtained. The sensors were installed on a rigid base in order to obtain a higher stiffness and force transmissibility therefore obtaining a strong vibration signal input acting on the cantilevered beam. A wide range of research and proposed models shows that the maximum power output of a resonant energy harvester subjected to an ambient vibration is reached when the natural angular frequency (𝜔𝑛) of the mass-spring structure is tuned to the natural frequency of ambient vibrations (𝜔). Key Terms  Energy Harvester, Natural Frequency, Resonance, Vibration Spectrum.