本文選題：徑向極化 + 徑向振動(dòng)　； 參考：《陜西師范大學(xué)》2015年博士論文

【摘要】：在超聲清洗、超聲處理等功率超聲的應(yīng)用中,換能器是以實(shí)現(xiàn)向介質(zhì)輻射大功率聲能為目的。通常功率超聲換能器大都采用結(jié)構(gòu)簡(jiǎn)單、機(jī)電耦合系數(shù)及機(jī)電轉(zhuǎn)換效率高、且易于優(yōu)化設(shè)計(jì)的縱向振動(dòng)形式的夾心式壓電陶瓷超聲換能器。但傳統(tǒng)的縱向振動(dòng)夾心式換能器由于橫向尺寸要小于輻射聲波波長(zhǎng)的四分之一,因此,換能器的聲波輻射面積受到限制；另外,此類換能器的輻射射能量基本上是沿著換能器的縱軸方向輻射,不能實(shí)現(xiàn)超聲能量的空間輻射,這使得超聲波作用范圍受到了限制；還有傳統(tǒng)換能器的共振頻率單一難以調(diào)整,不能滿足某些應(yīng)用場(chǎng)合的需要。因此,基于以上原因,為了適應(yīng)功率超聲新技術(shù)的要求,克服傳統(tǒng)換能器存在的一些弊端,本文提出了一種新型結(jié)構(gòu)的換能器,該換能器由徑向極化的壓電陶瓷圓管和內(nèi)外金屬圓管在徑向復(fù)合而成。該換能器結(jié)構(gòu)簡(jiǎn)單,對(duì)傳統(tǒng)換能器是一種創(chuàng)新,對(duì)于發(fā)展新型的超聲換能器、改善現(xiàn)有超聲技術(shù)的應(yīng)用效果、開發(fā)新的超聲技術(shù)及應(yīng)用領(lǐng)域具有理論指導(dǎo)意義和實(shí)際應(yīng)用價(jià)值。本文主要對(duì)以下幾方面進(jìn)行研究：(1)金屬管作為超聲換能器振動(dòng)系統(tǒng)的重要組成部分,對(duì)其徑向振動(dòng)特性進(jìn)行了研究。從管長(zhǎng)與半徑關(guān)系將其分為三類來(lái)進(jìn)行研究,分別是縱向尺寸遠(yuǎn)小于徑向尺寸的薄圓盤圓環(huán)、縱向尺寸遠(yuǎn)大于徑向尺寸的金屬長(zhǎng)圓管以及縱徑尺寸接近的金屬圓柱、圓管。從平面應(yīng)力問(wèn)題出發(fā),推導(dǎo)出金屬薄圓盤、圓環(huán)徑向振動(dòng)的機(jī)電等效電路,得到其徑向振動(dòng)頻率方程,由此得到徑向尺寸與徑向共振頻率間的相互關(guān)系。通過(guò)ANSYS有限元模擬仿真表明理論計(jì)算與數(shù)值仿真是一致的。從平面應(yīng)變問(wèn)題出發(fā),推導(dǎo)出金屬長(zhǎng)圓管徑向振動(dòng)的機(jī)電等效電路,得到其徑向振動(dòng)頻率方程,由此得到尺寸與徑向共振頻率間的相互關(guān)系。通過(guò)ANSYS有限元模擬仿真表明理論計(jì)算與數(shù)值仿真是一致的,通過(guò)數(shù)值仿真說(shuō)明薄壁金屬長(zhǎng)圓管輻射器在徑向有較強(qiáng)的輻射聲場(chǎng)。采用表觀彈性法來(lái)分析縱徑尺寸接近的實(shí)心、空心圓柱,將實(shí)心、空心圓柱的耦合振動(dòng)等效為兩個(gè)一維振動(dòng),它們通過(guò)機(jī)械耦合系數(shù)相互作用。通過(guò)分析可知圓柱耦合振動(dòng)的機(jī)電等效電路由細(xì)棒縱向振動(dòng)和薄圓盤或圓環(huán)徑向振動(dòng)等效電路構(gòu)成。并據(jù)此得到各自縱向、徑向振動(dòng)的頻率方程。獲得在縱向與徑向產(chǎn)生強(qiáng)烈耦合振動(dòng)的條件。有限元數(shù)值模擬了圓柱的振動(dòng)特性,模擬結(jié)果與實(shí)驗(yàn)結(jié)果相吻合。(2)徑向極化的壓電陶瓷管作為徑向夾心式超聲換能器的激勵(lì)單元,對(duì)其徑向振動(dòng)特性進(jìn)行了研究。依據(jù)壓電管縱徑尺寸間的關(guān)系,對(duì)壓電短圓管、長(zhǎng)壓電管以及縱徑尺寸接近的壓電管分別對(duì)其分析。從平面應(yīng)力問(wèn)題出發(fā),推導(dǎo)出徑向極化壓電短圓管徑向振動(dòng)的機(jī)電等效電路,從而得到其共振和反共振頻率方程。由此得到幾何尺寸與共振頻率、反共振頻率以及有效機(jī)電耦合系數(shù)間的相互關(guān)系,最后用ANSYS有限元軟件數(shù)值仿真,結(jié)果與理論計(jì)算一致,說(shuō)明理論的正確性。從平面應(yīng)變問(wèn)題出發(fā),用相似于壓電短圓管的方法,推導(dǎo)壓電陶瓷長(zhǎng)圓管徑向振動(dòng)的機(jī)電等效電路,得到其共振和反共振頻率方程。得到幾何尺寸與共振頻率、反共振頻率以及有效機(jī)電耦合系數(shù)間的相互關(guān)系,并用ANSYS有限元軟件數(shù)值仿真,結(jié)果與理論計(jì)算一致,說(shuō)明理論的正確性。采用表觀彈性法研究縱徑尺寸接近的壓電管,將其耦合振動(dòng)等效為縱向和徑向振動(dòng),得到各自的機(jī)電等效電路和頻率方程。有限元數(shù)值模擬了圓柱的振動(dòng)特性,模擬結(jié)果與實(shí)驗(yàn)結(jié)果相吻合。(3)提出一種新型結(jié)構(gòu)的徑向夾心式超聲換能器,按縱徑尺寸關(guān)系,分別對(duì)徑向夾心式短管換能器、徑向夾心式長(zhǎng)圓管換能器以及耦合振動(dòng)的徑向夾心式換能器進(jìn)行分析。將換能器各組成部分在徑向相連,得到各換能器的機(jī)電等效電路,從而推導(dǎo)出各自共振與反共振頻率方程,由此得到幾何尺寸與共振、反共振頻率以及有效機(jī)電耦合系數(shù)間的關(guān)系。設(shè)計(jì)、加工了三種徑向夾心式換能器,理論計(jì)算、數(shù)值仿真、實(shí)驗(yàn)測(cè)試結(jié)果比較一致。對(duì)各種換能器在水中的輻射聲場(chǎng)進(jìn)行了模擬仿真,仿真表明短管、長(zhǎng)圓管換能器在液體中做徑向輻射,且在水中具有管內(nèi)聲場(chǎng)聚焦作用�？v徑尺寸接近的徑向夾心換能器可在徑向與縱向全方位的輻射,并且電壓發(fā)射響應(yīng)帶寬也較寬。該類換能器可應(yīng)用于功率超聲,如超聲液體處理、聲化學(xué)、超聲萃取等。
[Abstract]:In the application of ultrasonic cleaning, ultrasonic processing and other power ultrasonic applications, the transducer is designed to achieve high power sound energy radiation to the medium. Usually, the ultrasonic transducer of the piezoelectric ceramic transducer is mostly used for the piezoelectric ceramic ultrasonic transducer with simple structure, the electromechanical coupling coefficient and the high efficiency of electromechanical conversion, and it is easy to optimize the design of the longitudinal vibration mode. The traditional longitudinal vibration sandwich transducer is less than 1/4 of the wavelength of the radiation sound wave. Therefore, the acoustic radiation area of the transducer is limited. In addition, the radiation energy of the transducer is basically radiated along the longitudinal axis of the transducer, and the space radiation of the ultrasonic energy can not be realized, which makes the ultrasonic wave. The range of action is limited, and the resonant frequency of the traditional transducer is difficult to adjust to meet the needs of some applications. Therefore, based on the above reasons, in order to adapt to the requirements of the new power ultrasonic technology and overcome the disadvantages of the traditional transducer, a new type of transducer is proposed in this paper. The radial polarized piezoceramic circular tube and the inner and outer metal tube are combined in radial direction. The structure of the transducer is simple, and it is an innovation for the traditional transducer. It has theoretical guiding significance and practical application value for developing new ultrasonic transducer, improving the application effect of the existing ultrasonic technology and developing new ultrasonic technology and application fields. This paper mainly studies the following aspects: (1) as an important part of the vibration system of an ultrasonic transducer, the metal tube is a part of the vibration system of the ultrasonic transducer, and its radial vibration characteristics are studied. It is divided into three types from the relationship between the length and the radius of the tube, and the longitudinal size is far smaller than the radial size, and the longitudinal size is far larger than the radial. A metal circular tube of size and a metal cylinder and a circular tube with close longitudinal dimensions. Based on the plane stress problem, an electromechanical equivalent circuit of a thin metal disk and a radial vibration is derived. The radial vibration frequency equation is obtained. The relationship between the radial vibration frequency and the radial resonance frequency is obtained. The simulation table is simulated by the ANSYS finite element method. The theoretical calculation is consistent with the numerical simulation. Based on the plane strain problem, the electromechanical equivalent circuit of the radial vibration of the metal long circular tube is derived, and the radial vibration frequency equation is obtained. Thus the relationship between the size and the radial resonance frequency is obtained. The simulation results of the ANSYS finite element simulation show that the theoretical calculation is in agreement with the numerical simulation. The numerical simulation shows that the radiant field of the thin-walled tube radiator is stronger in the radial direction. Using the epigenetic elastic method to analyze the solid, hollow cylinder, the coupling vibration of solid and hollow cylinders is equivalent to two one-dimensional vibrations, and they interact through the mechanical coupling coefficient. Through analysis, the cylindrical coupling is known. The electromechanical equivalent circuit of the vibration is composed of the longitudinal vibration of a fine rod and the equivalent circuit of the radial vibration of a thin disk or a circular ring. The frequency equations of the longitudinal and radial vibration are obtained accordingly. The conditions of strong coupling vibration are obtained in the longitudinal and radial directions. The finite element numerical simulation is used to simulate the vibration characteristics of the cylinder, and the simulation results are in agreement with the experimental results. (2 The radial polarization piezoelectric ceramic tube is used as the excitation unit of the radial sandwich transducer, and its radial vibration characteristics are studied. According to the relationship between the longitudinal diameter and size of the piezoelectric tube, the piezoelectric short circular tube, the long pressure tube and the piezoelectric tube near the longitudinal diameter are separately analyzed. The radial polarization is derived from the plane stress problem. The electro-mechanical equivalent circuit of the radial vibration of the piezoelectric short circular tube is obtained, and the resonance frequency and the anti resonance frequency equation are obtained. The relationship between the geometric size and resonance frequency, the resonance frequency and the effective electromechanical coupling coefficient is obtained. Finally, the numerical simulation of the ANSYS finite element software is used to agree with the theoretical calculation, indicating the correctness of the theory. Based on the plane strain problem, the electromechanical equivalent circuit of the radial vibration of the piezoceramic long circular tube is derived by using the method similar to the piezoelectric short circular tube. The resonance and anti resonance frequency equations are obtained. The relationship between the geometric size and the resonance frequency, the resonance frequency and the effective electromechanical coupling coefficient are obtained, and the numerical simulation of the ANSYS finite element software is used. The results are in agreement with the theoretical calculation, indicating the correctness of the theory. The piezoelectric tubes with close longitudinal dimensions are studied by the epigenetic elastic method, and their coupling vibration is equivalent to the longitudinal and radial vibration, and their respective electromechanical equivalent circuits and frequency equations are obtained. The finite element numerical simulation is used to simulate the vibration characteristics of the cylinder. The simulation results are in agreement with the experimental results. (3) (3) A new type of radial sandwich transducer is used to analyze the radial sandwich type short tube transducer, radial sandwich type long circular tube transducer and coupling vibration radial sandwich transducer respectively. The electromechanical equivalent circuit of each transducer is obtained by connecting the components of the transducer in the radial direction. The relations between the geometric size and resonance, the resonance frequency and the effective electromechanical coupling coefficient are derived. Three radial sandwich transducers are designed, the theoretical calculation, the numerical simulation and the experimental results are consistent. The radiation sound field of various transducers in the water is simulated. The simulation shows that the short tube, the long circular tube transducer is radially radiating in the liquid and has the focus of the sound field in the water. The radial sandwich transducer with close longitudinal diameter can be radially and longitudinally radiated, and the voltage emission response bandwidth is wide. The transducer can be applied to power ultrasonic, such as ultrasonic liquid treatment. Sonochemistry, ultrasonic extraction and so on.
【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB552

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本文編號(hào)：1999194