Pervasive networks of wi reless sensors and communication nodes have been developed during past decades and most of them are powered by fixed-energy sources, e.g., wiring power and batteries. However, these traditional energy sources are impractical for powering wireless devices due to their inherent limitations, e.g., the high setup cost of wiring power and the finite life span of batteries. In view of these facts, more attentions have been drawn on vibration energy sources existing in ambient environment where sensors operate. Dozens of different types of vibrat ion energy scavenging devices have been developed, which are mainly consisted of mechanical systems coupled with transduction mechanisms. The linear mechanical system has been used in most of existing vibration generators. The main drawback of such system is that it has a rather narrow bandwidth, meaning that the device can only effectively harvest vibration energy when the resonance frequency of the system coincides with the excitation frequency. Various methods have been proposed recently 10 overcome the drawback including utili sing mechan ical systems with non-linear mechanisms in order to increase the bandwidth of vibration energy scavenging devices. The dissertation is intended 10 fi nd a practically effective non-linear mechanical system with desirab le dynamic behaviours for vibration energy scavenging devices. To do so, we first examined three non-linear mechanisms numerically to find the most desirable one based on the corresponding typical mechanical systems. The Numerical Simulation (NS) method built in Matlab has been used to explore the static and dynamic characteristics of these systems with hardening and softening mechanisms
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:601178 |
| Date | January 2013 |
| Creators | Deng, Jiewen |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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