CN111614285A

CN111614285A - Asymmetric cantilever beam type piezoelectric broadband vibration energy collecting device

Info

Publication number: CN111614285A
Application number: CN202010495231.XA
Authority: CN
Inventors: 邹爱成; 沈星; 王群英; 刘忠; 宋小辉; 韩兴国
Original assignee: Nanjing University of Aeronautics and Astronautics; Guilin University of Aerospace Technology
Current assignee: Nanjing University of Aeronautics and Astronautics; Guilin University of Aerospace Technology
Priority date: 2020-06-03
Filing date: 2020-06-03
Publication date: 2020-09-01

Abstract

The invention discloses an asymmetric cantilever beam type piezoelectric broadband vibration energy collecting device which comprises a first mass block, a first cantilever beam and a second cantilever beam, wherein the first cantilever beam and the second cantilever beam are arranged on the first mass block at intervals, a base is arranged at the other end of the first cantilever beam, a second mass block is arranged at the other end of the second cantilever beam, a group of first piezoelectric patches are arranged on the first cantilever beam at intervals, a group of second piezoelectric patches are arranged on the second cantilever beam at intervals, and the length of the first cantilever beam is greater than that of the second cantilever beam. The collecting device can effectively widen the frequency band of the piezoelectric structure responding to the environmental vibration and effectively improve the energy collecting efficiency of the piezoelectric structure to the environmental vibration under the same comparable condition.

Description

Asymmetric cantilever beam type piezoelectric broadband vibration energy collecting device

Technical Field

The invention relates to a vibration energy collecting technology, in particular to an asymmetric cantilever beam type piezoelectric broadband vibration energy collecting device.

Background

A multi-cantilever beam type broadband energy harvesting structure is designed in the summer, and as shown in fig. 3, a plurality of cantilever beam piezoelectric vibrators form a multi-piezoelectric vibrator vibration array, so that the resonance frequency band of the piezoelectric vibrator is widened, and the piezoelectric vibrator can generate resonance or approximate resonance within a frequency range. By properly designing the length of the cantilever beam and the size of the mass block, the cantilever beam can realize resonance at a plurality of similar frequency points, and further can realize energy collection in a wide frequency band.

The Liu Shao steel designs the structure of the two-degree-of-freedom piecewise linear piezoelectric vibration energy collecting device, and as shown in figure 4, the device consists of a two-degree-of-freedom main cantilever beam and a single-degree-of-freedom driven cantilever beam. The piezoelectric plate as the energy conversion component is attached to the first section of the two-freedom-degree main beam, and the mass blocks positioned in the middle and at the top of the main beam are used as vibration masses. And a distance gap is reserved between the mass block and the driven beam, and when external excitation at the base is large enough, the mass block collides with the driven beam because the displacement of the mass block in each vibration period is larger than the gap distance. The structure can generate response frequencies of two modes, but has the problem of relatively complicated structure.

The defects of the two structures are that the structure is complex, and each beam is only provided with one whole piezoelectric sheet, so that the energy collection efficiency is low.

Disclosure of Invention

The invention aims to provide an asymmetric cantilever beam type piezoelectric broadband vibration energy collecting device aiming at the defects in the prior art. The collecting device can effectively widen the frequency band of the piezoelectric structure responding to the environmental vibration and effectively improve the energy collecting efficiency of the piezoelectric structure to the environmental vibration under the same comparable condition.

The technical scheme for realizing the purpose of the invention is as follows:

the utility model provides an asymmetric cantilever beam formula piezoelectricity wide band vibration energy collection device, includes first quality piece, and first cantilever beam and the second cantilever beam that the interval set up on first quality piece, the other end of first cantilever beam is equipped with the base, the other end of second cantilever beam is equipped with the second quality piece, is equipped with the first piezoelectric patches that a set of interval set up on the first cantilever beam, is equipped with the second piezoelectric patches that a set of interval set up on the second cantilever beam, the length of first cantilever beam is greater than the length of second cantilever beam.

The first cantilever beam and the second cantilever beam are made of conductive metal materials.

And the gap between the first cantilever beam and the second cantilever beam is 5 mm.

The density of the first cantilever beam and the second cantilever beam is 2.7x10³kg/m³The Young's modulus was 60 GPa.

The weight of the first mass block is 5.06g, and the weight of the second mass block is 2.89 g.

The density of the first piezoelectric sheet and the second piezoelectric sheet is 7.5x10³kg/m³The Young's modulus was 66 GPa.

The number of the first piezoelectric sheets is 2, and the gap between the 2 first piezoelectric sheets is 1 mm.

The number of the second piezoelectric sheets is 2, and the gap between the 2 second piezoelectric sheets is 1 mm.

The collecting device effectively widens the frequency band of the piezoelectric structure responding to the environmental vibration and effectively improves the energy collecting efficiency of the piezoelectric structure responding to the environmental vibration under the same comparable condition.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment;

FIG. 2 is a side view of the embodiment;

FIG. 3 is a schematic diagram of a piezoelectric energy harvesting structure of a Sieve design in the prior art;

FIG. 4 is a schematic view of a prior art collection device designed for a Liu Shao steel;

FIG. 5 is a frequency response graph of an embodiment;

fig. 6 is a schematic diagram of the variation of the output electric power with the excitation frequency of the embodiment.

In fig. 1, 1 is a first cantilever beam 2, a second cantilever beam 3, a first mass block 4, a base 5, a second mass block 6, a first piezoelectric sheet 7 and a second piezoelectric sheet.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples, but the invention is not limited thereto.

Example (b):

referring to fig. 1 and 2, the asymmetric cantilever type piezoelectric broadband vibration energy collecting device comprises a first mass block 3, a first cantilever beam 1 and a second cantilever beam 2 which are arranged on the first mass block 3 at intervals, a base 4 is arranged at the other end of the first cantilever beam 2, a second mass block 5 is arranged at the other end of the second cantilever beam 2, a group of first piezoelectric patches 6 which are arranged at intervals are arranged on the first cantilever beam 1, a group of second piezoelectric patches 7 which are arranged at intervals are arranged on the second cantilever beam 2, and the length of the first cantilever beam 1 is greater than that of the second cantilever beam 2.

The material of the first cantilever beam 1 and the second cantilever beam 2 is a conductive metal material, in this case, aluminum.

And the gap between the first cantilever beam 1 and the second cantilever beam 2 is 5 mm.

The density of the first cantilever beam 1 and the second cantilever beam 2 is 2.7x10³kg/m³The Young's modulus was 60 GPa.

The first mass block 3 has a weight of 5.06g and the second mass block 5 has a weight of 2.89 g.

The density of the first piezoelectric sheet 6 and the second piezoelectric sheet 7 is 7.5x10³kg/m³The Young's modulus was 66 GPa.

The number of the first piezoelectric sheets 6 is 2, and the gap between the 2 first piezoelectric sheets 6 is 1 mm.

The number of the second piezoelectric sheets 7 is 2, and the gap between the 2 second piezoelectric sheets 7 is 1 mm.

In the embodiment, the first cantilever beam 1 has the dimensions of 70mm in length, 11mm in width and 0.6mm in height, and the second cantilever beam 2 has the dimensions of 60mm in length, 11mm in width and 0.6mm in height.

In this example, the first mass block 3 and the second mass block 5 are made of cast iron, the first mass block 3 has a length of 5mm, a width of 26mm and a height of 5mm, and the second mass block 5 has a length of 5mm, a width of 11mm and a height of 7 mm.

In this example, the first piezoelectric patch 6 and the second piezoelectric patch 7 are made of piezoelectric ceramic PZT-5H, wherein each first piezoelectric patch 6 has a length of 60mm, a width of 5mm, and a height of 0.2mm, and each second piezoelectric patch 7 has a length of 45mm, a width of 5mm, and a height of 0.2 mm.

And (3) testing:

the base end of the first cantilever beam 1 is fixed on the vibration exciting table, and vibration with the amplitude of 5mm and the scanning frequency of 0-100 Hz is applied to the vibration exciting table.

And (3) frequency response testing: when the vibration table vibrates, the displacement of the first cantilever beam 1 at the end of the first mass block 3 and the displacement of the second cantilever beam 2 at the end of the second mass block 5 reflect the response of the device of the present example to the vibration frequency, and as can be seen from fig. 5: when the excitation frequency is 28.01Hz, the first cantilever beam 1 has the maximum amplitude, so the first-order response frequency of the device is 28.01 Hz; at an excitation frequency of 34.02Hz, the second cantilever beam 2 has a maximum amplitude, so the second order response frequency of the device of the present example is 34.02 Hz.

And (3) testing output power: it was found that the variation of the output electric power of the device of this example with the excitation frequency is as shown in fig. 6, when the excitation frequency is 29.01Hz, the output power of the PZT1 and the PZT2 is the largest, the total output power of the structure is 20.05mW, when the excitation frequency is 29.01Hz, the output power of the 2 first piezoelectric plates 6 is the largest, the total output power of the device of this example reaches the first peak value and 20.05mW, when the excitation frequency is 35.40Hz, the output power of the 2 second piezoelectric plates 7 is the largest, the total output power of the device of this example reaches the second peak value and 12.95mW, when the excitation frequency is between 28.12Hz and 36.58Hz, the total output power of the device of this example exceeds 5mW, that is, the device of this example has a good response to the vibration with the environmental vibration frequency between 28.12Hz and 36.58Hz, and realizes broadband efficient energy collection.

Claims

1. The utility model provides an asymmetric cantilever beam formula piezoelectricity wide band vibration energy collection device which characterized in that, includes first quality piece, and first cantilever beam and the second cantilever beam that sets up at the interval on first quality piece, the other end of first cantilever beam is equipped with the base, the other end of second cantilever beam is equipped with the second quality piece, is equipped with the first piezoelectric patches that a set of interval set up on the first cantilever beam, is equipped with the second piezoelectric patches that a set of interval set up on the second cantilever beam, the length of first cantilever beam is greater than the length of second cantilever beam.

2. The asymmetric-cantilever piezoelectric broadband vibration energy harvesting device according to claim 1, wherein the material of the first cantilever beam and the second cantilever beam is a conductive metal material.

3. The asymmetric-cantilever piezoelectric broadband vibration energy harvesting device according to claim 1, wherein the gap between the first cantilever beam and the second cantilever beam is 5 mm.

4. The asymmetric cantilever piezoelectric broadband vibration energy harvesting device of claim 1 wherein the density of the first and second cantilever beams is 2.7x10³kg/m³The Young's modulus was 60 GPa.

5. The device of claim 1 wherein the first mass has a weight of 5.06g and the second mass has a weight of 2.89 g.

6. The device of claim 1 wherein the first and second piezoelectric patches have a density of 7.5x10³kg/m³The Young's modulus was 66 GPa.