Design and optimization of vibration energy harvester for naval ship applications

• Main Author: Lee, Chun Yu
• Other Authors: Yang Yaowen
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/61160
• Institution: Nanyang Technological University

The paper reviews on linear piezoelectric harvesters (PEH) with the research focus on the substrate material strength and optimal geometric parameters. The application of the PEH is targeted at powering wireless sensors in naval ships, eliminating the use of traditional battery sources that are costly in maintenance and detrimental to the environment in its disposal. The wireless sensors nodes are capable to monitor the ambient temperature, pressure, gas toxicity, fire detection and strain, which are useful in naval ship applications. For comparison between power produced and required, the average power consumption of LORD Microstrain DVRT-Link-Displacement sensor node is 15 mW while a PEH with the substrate geometrical parameters of 90 mm in length, 10mm width and 0.6 mm in thickness operating at 14 Hz and 0.2 g acceleration is able to produce an approximate output power of 2 mW. The first portion of the paper discusses on a suitable substrate material for the PEH. A robust substrate material will ensure that the design life of a PEH will sufficiently long to match the device that it is applied on. The first substrate material Aluminium AL1100 was eliminated due to the fatigue failure observed during the experiments. Fiberglass (G10F4) is then proposed as the second substrate to be tested due to its high fatigue strength. However, the power output was 12.09 times lesser than AL1100 as the substrate with similar geometric parameters. The third substrate material, AL7075, is recommended as the best material in this paper, due to the higher fatigue strength and similar young’s modulus as the AL1100. The second portion of the paper investigates the effects of geometric parameters on the power output of PEH. The effects of varying length are explored in this paper as width, thickness and tip mass have already been explored in previous researches. The results have shown that optimal length can be obtained as opposed to the theory that length is inversely proportional to output power. Lastly, non-linearity in the data has been observed in the experiments at higher accelerations as opposed to the linear equations assumed in this paper. The effects of non-linearity are found at higher accelerations, which may not occur in practical applications. Thus, linearity can be assumed in most cases of linear piezoelectric harvesting.