Design method of two-degree-of-freedom piezoelectric vibrator for realizing broadband response

Abstract

The invention discloses a design method of a two-degree-of-freedom piezoelectric vibrator for realizing broadband response. The method comprises the following steps of: step 1, respectively taking upper and lower limits of a prospective frequency band as inherent frequency initial values of two single-degree-of-freedom cantilever beams, and determining the elasticity coefficients k1 and k2 of thetwo single-degree-of-freedom cantilever beams and the masses m1 and m2 of two single-degree-of-freedom cantilever beam piezoelectric vibrators; step 2, determining the initial value of the elasticitycoefficient k3 of a connection spring according to the prospective ratio of the first order resonance frequency to the second order resonance frequency of the two-degree-of-freedom vibrator; step 3, based on above parameters, establishing a finite element model of the two-degree-of-freedom piezoelectric vibrator, under constraints of frequency band, structure size and material characteristics, for the aim of realizing maximum output power, regulating four parameters including thickness of a piezoelectric layer, thickness of the cantilever beams, size of mass blocks and elasticity coefficient of the connection spring. The method realizes the broadband response of the two-degree-of-freedom piezoelectric vibrator under the premise of keeping high-efficiency energy conversion.

Description

technical field [0001] The invention belongs to the technical field of energy supply-oriented piezoelectric environmental vibration energy acquisition, and relates to a design method of a two-degree-of-freedom piezoelectric vibrator that realizes broadband response, and is used to improve the structural parameters of the piezoelectric vibrator to the response rate of broadband vibration excitation Optimized design. Background technique [0002] With the rapid development of wireless sensor networks, embedded intelligent structures and other low power consumption and independent working systems, the demand for long-life independent power supply technology is becoming stronger and stronger. At present, the battery is still the preferred power source for this type of system, but the capacity of the battery is limited after all, and it needs to be replaced regularly, which brings great inconvenience to the application of the above-mentioned system. At the same time, extensive u...

AI Technical Summary

Problems solved by technology

At present, foreign scholars have designed a wide-band piezoelectric vibrator by pre-applying axial stress and micro-controlling frequency control technology using capacitive load changes, but this structure is more complicated, the cost is higher, and the energy conversion efficiency is low.

[0006] At present, there is still a lack of systematic design methods for the structure of piezoelectric vibrators. The design of piezoelectric vibrators usually only considers the demand for wide-frequency response (for example, multiple independent single-degree-of-freedom vibrators with different resonant frequency points are combined into a group, that is, Array type, to adapt to vibration excitation of different frequencies), or the demand for output power, without taking into account the requirements of these two aspects at the same time, and lack of consideration for the stability of the piezoelectric vibrator structure

[0007] Summarizing the existing piezoelectric vibrator design methods, it can be found that the single-degree-of-freedom structural piezoelectric vibrator designed by conventional methods has a narrow resonance frequency band, which is not conducive to the practical application of piezoelectric environmental vibration energy harvesting technology; The wide-band piezoelectric vibrator designed by the control method has a complex structure, lack of consideration in terms of structural stability, low energy conversion efficiency, and poor practicability

Although many design methods have been proposed on issues such as output power and broadband response, most of them are limited to solving one of the problems, and there is a lack of systematic guidance methods.

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