Meta-material vibration energy harvester

Abstract

A meta-material vibration energy harvester includes a housing element encapsulating a multiplicity of oscillators capable of harvesting a significant percentage of the total mechanical energy diffusely distributed throughout the vibrating structure, the harvester design resulting in a rapid transfer of mechanical energy entering it via the housing element from the element to the oscillators wherein the energy remains trapped while accumulating over an extended time, the percentage of energy transfer primarily depending on the ratios of the sum of the oscillator masses to the sum of the housing mass and of the measure of the mass of the vibrating structure and of the width of the band spanned by the oscillators to its center frequency, both the relevant measure of the vibrating structure mass and the values of the mass and frequency ratios that maximize the percentage of internal energy transfer depending on the harvesting scenario.

Description

FIELD OF THE INVENTION[0001]The invention relates to a vibration energy harvester comprised of a large number of oscillators encapsulated in a housing element, combined with mechanical / electrical energy converters, one for each oscillator, and the internal circuitry for collecting the individual electric currents and outputting their total, via the housing element. The invention is applicable to virtually all structures and vibration fields. Moreover, when used in multiplicity, the invention is capable of harvesting a significant percentage of the total available energy in a vibrating structure.BACKGROUND OF THE INVENTION[0002]In search of the solution to the world energy crisis, researchers and industry have focused their efforts on harnessing energy from alternative energy sources, most notably the sun, wind, and ocean waves.[0003]Technologies for harvesting energy from these sources are in their infancy, though significant progress has been made. However, the efficiency of existi...

AI Technical Summary

Benefits of technology

[0073]Starting with the top most three graphs: For these the mass ratio, Σmsj) / Ms=10−4, a value chosen to be so small as to result in the internal oscillators having no effect on the behavior of the housing mass. This is reflected in a housing mass velocity history having a time harmonic variation at the resonant frequency of the housing element in isolation, modulated by an exponentially decaying envelope, appropriate for the strength of the viscous damper grounding the mass element. The strength of the viscous damper is such that virtually all of the mechanical energy is removed from the system before what would be the arrival time of the second force pulse, t=400. The second and third of the topmost three graphs show the amplitude and phase spectra defined on the time series; the three graphs are what one would expect.

[0074]Jumping down to the case for which the mass ratio, Σjmsj / Ms≈0.005, it is clearly seen that the velocity of the housing element returns to zero in a normalized time approximately equal to 8, corresponding to Ω−1, remaining approximately equal to zero thereafter. For this case, which is close to optimum, the sum of the masses of the internal oscillators is approximately 0.5% of the magnitude of the base mass, a mass ratio that is surprisingly small for the internal oscillators to have such a profound effect on the base mass motion. Referring to the amplitude spectrum defined on the housing mass velocity, this is seen to be relatively fiat over the frequency band. By association, it is for mass ratios approximately equal to 0.005 that the strength of the first net internal force pulse approximately equals 1.

Problems solved by technology

However, the efficiency of existing technologies is limited, and resulting environmental issues, such as noise and microclimate change, have become increasingly problematic.

Unless these technologies can be dramatically improved, their energy harvesting potential will be limited.

The state-of-the-art of VEH, as measures by patent applications and awards, are limited to micro-electro-mechanical systems (MEMS) that are only capable of generating very small amounts of power measures in the order of milliwatts.

Typically, the mass of an efficient VD is a large enough percentage of that of the VS to negatively impact design criteria for the VS not related to the VD.

The design according to this known device results in the rapid transfer of a significant percentage of the energy drawn into the device, to the internal oscillators wherein it “remains trapped indefinitely,” using the terminology in the reference.

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