الملخص الإنجليزي
Harvesting energy from ambient vibration opens the way of powering small-scale systems
without the need of battery replacements. Many studies having been conducted considering the
use of this new technology as it is considered a clean energy source. This thesis starts with an
exploration and comparison approach on the use of electromagnetic, piezoelectric and hybrid
transduction types in noncontinuous system to harvest vibration through as well as the effect
of adding an impact oscillator into the main harvester system on the harvested power and
frequency bandwidth. It was observed that adding single or double impact oscillator into
piezoelectric or electromagnetic harvester resulted in widening the frequency harvesting
bandwidth of the vibration-based harvester. The effect of having duale impact oscillator
combing both previous types into one harvester produced the optimum frequency range that
can be harvested compared to the other forementioned types. Adding nonlinearity into system
stiffness and impact oscillator was also examined. Having such nonlinear effect helped in
relatively widening of the harvesting bandwidth of the harvester as compared the linear case.
Moving to continuous system represented by the cantilever beam and choosing to have just
electromagnetic transducer to harvest vibration, it was concluded that the usage of impact oscillators in a nonlinear electro-magnetic cantilever, the harvested power simulation results
indicate a spectrum of resonant frequencies of the vibrating cantilever beam that extends
beyond its basic natural frequency. Moreover, as the nonlinearity of both the impact oscillators
forces and the magnetic flux is increased, the harvested power of the enhanced system shows
wider bands in its respective frequency response. Using FEA, it was clear that considering two
magnets in repulsion generates higher values mainly due to the strong nonlinear transient
magnetic flux, resulting into few times more power as compared to the case of considering
only one magnet in the system.
