EXPERIMENTAL STUDY OF ENERGY ABSORPTION PROPERTIES OF GRANULAR MATERIALS UNDER LOW FREQUENCY VIBRATIONS

2004 ◽  
Vol 18 (17n19) ◽  
pp. 2708-2712
Author(s):  
MAO-BIN HU ◽  
XIANG-ZHAO KONG ◽  
QING-SONG WU ◽  
ZHEN-GANG ZHU
Keyword(s):  
Experimental Study ◽  
Granular Materials ◽  
Energy Absorption ◽  
Vibration Frequency ◽  
Absorption Rate ◽  
Low Frequency ◽  
Vibration Energy ◽  
Torsion Pendulum ◽  
Absorption Properties ◽  
Low Frequency Vibration

The low frequency vibration energy absorption properties of granular materials have been investigated on an Invert Torsion Pendulum (ITP). The energy absorption rate of granular material changes nonlinearly with amplitude under low frequency vibration. The frequency of ITP system increases a little with granular materials in the holding cup. The vibration frequency of ITP system does not change with time.

scholarly journals Improving functionality of vibration energy harvesters using magnets

2012 ◽  
Vol 23 (13) ◽  
pp. 1433-1449 ◽  
Author(s):  
Lihua Tang ◽  
Yaowen Yang ◽  
Chee-Kiong Soh
Keyword(s):  
Experimental Study ◽  
Energy Harvesting ◽  
Transition Region ◽  
Parametric Study ◽  
Low Frequency ◽  
Design Guidelines ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Energy Harvesters ◽  
Low Frequency Vibration

In recent years, several strategies have been proposed to improve the functionality of energy harvesters under broadband vibrations, but they only improve the efficiency of energy harvesting under limited conditions. In this work, a comprehensive experimental study is conducted to investigate the use of magnets for improving the functionality of energy harvesters under various vibration scenarios. First, the nonlinearities introduced by magnets are exploited to improve the performance of vibration energy harvesting. Both monostable and bistable configurations are investigated under sinusoidal and random vibrations with various excitation levels. The optimal nonlinear configuration (in terms of distance between magnets) is determined to be near the monostable-to-bistable transition region. Results show that both monostable and bistable nonlinear configurations can significantly outperform the linear harvester near this transition region. Second, for ultra-low-frequency vibration scenarios such as wave heave motions, a frequency up-conversion mechanism using magnets is proposed. By parametric study, the repulsive configuration of magnets is found preferable in the frequency up-conversion technique, which is efficient and insensitive to various wave conditions when the magnets are placed sufficiently close. These findings could serve as useful design guidelines when nonlinearity or frequency up-conversion techniques are employed to improve the functionality of vibration energy harvesters.

scholarly journals Enhanced low-frequency vibration energy harvesting with inertial amplifiers

2021 ◽  
pp. 1045389X2110322
Author(s):  
Sondipon Adhikari ◽  
Arnab Banerjee
Keyword(s):  
Low Frequency ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Micro Scale ◽  
Energy Harvesters ◽  
Low Frequency Vibration ◽  
Different Types ◽  
Mechanical Approach ◽  
Ambient Excitation ◽  
Piezoelectric Vibration

Piezoelectric vibration energy harvesters have demonstrated the potential for sustainable energy generation from diverse ambient sources in the context of low-powered micro-scale systems. However, challenges remain concerning harvesting more power from low-frequency input excitations and broadband random excitations. To address this, here we propose a purely mechanical approach by employing inertial amplifiers with cantilever piezoelectric vibration energy harvesters. The proposed mechanism can achieve inertial amplification amounting to orders of magnitude under certain conditions. Harmonic, as well as broadband random excitations, are considered. Two types of harvesting circuits, namely, without and with an inductor, have been employed. We explicitly demonstrate how different parameters describing the inertial amplifiers should be optimally tuned to maximise harvested power under different types of excitations and circuit configurations. It is possible to harvest five times more power at a 50% lower frequency when the ambient excitation is harmonic. Under random broadband ambient excitations, it is possible to harvest 10 times more power with optimally selected parameters.

Development of a tunable low-frequency vibration energy harvester and its application to a self-contained wireless fatigue crack detection sensor

2018 ◽  
Vol 18 (3) ◽  
pp. 920-933 ◽  
Author(s):  
Suyoung Yang ◽  
Sung-Youb Jung ◽  
Kiyoung Kim ◽  
Peipei Liu ◽  
Sangmin Lee ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Energy Harvesting ◽  
Crack Detection ◽  
Energy Harvester ◽  
Low Frequency ◽  
Vibration Energy ◽  
Low Frequency Vibration ◽  
Resonance Frequencies ◽  
Energy Harvesting System ◽  
Fatigue Crack Detection

In this study, a tunable electromagnetic energy harvesting system, consisting of an energy harvester and energy harvesting circuits, is developed for harnessing energy from low-frequency vibration (below 10 Hz) of a bridge, and the harvesting system is integrated with a wireless fatigue crack detection sensor. The uniqueness of the proposed energy harvesting system includes that (1) the resonance frequencies of the proposed energy harvester can be readily tuned to the resonance frequencies of a host structure, (2) an improved energy harvesting efficiency compared to other electromagnetic energy harvesters is achieved in low-frequency and vibration, and (3) high-efficiency energy harvesting circuits for rectification are developed. Furthermore, the developed energy harvesting system is integrated with an on-site wireless sensor deployed on Yeongjong Grand Bridge in South Korea for online fatigue crack detection. To the best knowledge of the authors, this is the very first study where a series of low-frequency vibration energy harvesting, rectification, and battery charging processes are demonstrated under a real field condition. The field test conducted on Yeongjong Grand Bridge, where fatigue cracks have become of a great concern, shows that the proposed energy harvester can generate a peak voltage of 2.27 V and a root mean square voltage of 0.21 V from 0.18-m/s2 root mean square acceleration at 3.05 Hz. It is estimated the proposed energy harvesting system can harness around 67.90 J for 3 weeks and an average power of 37.42 µW. The battery life of the wireless sensor is expected to extend from 1.5 to 2.2 years. The proposed energy harvesting circuits, composed of the AC–DC and boost-up converters, exhibit up to 50% battery charging efficiency when the voltage generated by the proposed energy harvester is 200 mV or higher. The proposed boost-up converter has a 100 times wider input power range than a conventional boost-up converter with a similar efficiency.

A piezoelectric spring pendulum oscillator used for multi-directional and ultra-low frequency vibration energy harvesting

2018 ◽  
Vol 231 ◽  
pp. 600-614 ◽  
Author(s):  
Yipeng Wu ◽  
Jinhao Qiu ◽  
Shengpeng Zhou ◽  
Hongli Ji ◽  
Yang Chen ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Low Frequency ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Low Frequency Vibration
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