本文選題：聲表面波器件　切入點(diǎn)：非理想界面　出處：《西安交通大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：聲表面波器件、薄膜體聲波諧振器、壓電變壓器、石英晶體微天平以及質(zhì)量傳感器等電子器件在聲學(xué)、無(wú)損檢測(cè)、航空航天、電子通訊、醫(yī)學(xué)器械、主動(dòng)控制等眾多領(lǐng)域中應(yīng)用廣泛。本文從彈性力學(xué)的基本方程入手,借助于MATLAB計(jì)算軟件,從電子器件實(shí)際工程應(yīng)用的角度出發(fā),針對(duì)這些器件在使用過(guò)程中經(jīng)常遇到的結(jié)構(gòu)之間的弱連接、材料的非均勻分布以及變截面等問(wèn)題開(kāi)展了理論分析和數(shù)值研究。首先,以剪切-遲滯模型為基礎(chǔ),通過(guò)引入弱界面的電學(xué)非理想?yún)?shù)、阻尼系數(shù)等方式,詳細(xì)討論了含非理想界面的壓電層合結(jié)構(gòu)中B-G波的傳播、電學(xué)邊界條件的非理想性對(duì)壓電平板中厚度-扭轉(zhuǎn)波的影響、電激勵(lì)作用下壓電器件中的粘彈性弱界面以及由非理想界面激發(fā)出的高頻波等四個(gè)基本問(wèn)題。理論分析和數(shù)值計(jì)算的結(jié)果表明,非理想界面顯著影響器件的工作性能,主要體現(xiàn)在:非理想界面可以改變聲表面波器件中B-G波的存在條件;相對(duì)于力學(xué)特性而言,界面的電學(xué)非理想邊界條件對(duì)波傳播特性影響很小,可以忽略;界面的剛度系數(shù)與共振頻率直接相關(guān),進(jìn)而影響輸出幅值或輸出電壓與輸入電壓的比值、輸入導(dǎo)納、能流密度等性能指標(biāo),而阻尼系數(shù)對(duì)共振頻率幾乎沒(méi)有影響,但會(huì)顯著干擾器件的能量轉(zhuǎn)換效率;非理想界面的出現(xiàn)可以激發(fā)出新的厚度-扭轉(zhuǎn)波或厚度-剪切波,這是在界面理想情況下沒(méi)有出現(xiàn)的新現(xiàn)象。其次,應(yīng)用波函數(shù)展開(kāi)法和冪級(jí)數(shù)展開(kāi)法分別討論了功能梯度壓電壓磁半空間中的B-G波和材料參數(shù)沿長(zhǎng)度方向變化時(shí)板中的厚度-扭轉(zhuǎn)波。材料的非均勻分布可以從本質(zhì)上改變波的傳播特性,具體表現(xiàn)為:當(dāng)功能梯度壓電壓磁材料的各參數(shù)以同一指數(shù)規(guī)律變化時(shí),在其表面?zhèn)鞑サ腂-G波是頻散波;如果壓電損傷導(dǎo)致了材料參數(shù)沿板長(zhǎng)度方向分布不均,那么某些頻率范圍內(nèi)的厚度-扭轉(zhuǎn)波將呈現(xiàn)出能陷現(xiàn)象,能量主要集中在壓電板的某個(gè)區(qū)域。這些現(xiàn)象也是當(dāng)材料均勻分布時(shí)沒(méi)有出現(xiàn)過(guò)的。最后,利用Tiersten HF的近似方程和傅里葉級(jí)數(shù),通過(guò)改變諧振器的橫截面、石英晶體微天平中附加質(zhì)量層的厚度等手段,最終達(dá)到了激發(fā)能陷的目的。附加質(zhì)量層的慣性對(duì)振動(dòng)頻率起主導(dǎo)作用,振動(dòng)主要集中在器件較厚的區(qū)域,如果將器件設(shè)計(jì)成中間厚邊緣薄的形狀,將有利于器件的固定和能陷現(xiàn)象的發(fā)生。本研究揭示了弱界面、功能梯度材料、厚度的非均勻變化等因素對(duì)波傳播特性影響的物理機(jī)制,對(duì)壓電復(fù)合材料器件的分析和設(shè)計(jì)以及具體實(shí)驗(yàn)數(shù)據(jù)的測(cè)量具有重要的理論和指導(dǎo)意義。
[Abstract]:Surface acoustic wave devices, thin film bulk acoustic resonators, piezoelectric transformers, quartz crystal microbalance, mass sensors and other electronic devices in acoustics, nondestructive testing, aerospace, electronic communications, medical equipment, Active control is widely used in many fields. This paper starts with the basic equations of elastic mechanics, with the help of MATLAB software, from the point of view of practical engineering application of electronic devices. In this paper, the weak connections between structures, the non-uniform distribution of materials and the variable cross-section are analyzed and numerically studied. Firstly, based on the shear-hysteresis model, the shear hysteresis model is used to solve the problems of the weak connection between the structures, the non-uniform distribution of the material and the variable cross-section. The propagation of B-G wave in piezoelectric laminated structure with non-ideal interface is discussed in detail by introducing electrical nonideal parameters and damping coefficient of weak interface. The influence of non-ideality of electrical boundary condition on thickness torsional wave of piezoelectric plate is discussed in detail. Four basic problems, such as the viscoelastic weak interface and the high frequency wave excited by the non-ideal interface, are discussed in piezoelectric devices under electrical excitation. The theoretical analysis and numerical results show that the non-ideal interface significantly affects the performance of the device. The main results are as follows: the non-ideal interface can change the existence condition of B-G wave in saw devices, compared with the mechanical properties, the electrical nonideal boundary condition of the interface has little effect on the wave propagation characteristics, which can be ignored. The stiffness coefficient of the interface is directly related to the resonance frequency, which affects the output amplitude or the ratio of the output voltage to the input voltage, input admittance, energy flow density, etc., while the damping coefficient has little effect on the resonance frequency. But it can significantly interfere with the energy conversion efficiency of the device. The appearance of the non-ideal interface can excite new thick-torsion wave or thick-shear wave, which is a new phenomenon that does not appear in the ideal condition of the interface. Using the wave function expansion method and the power series expansion method, respectively, the thickness torsion wave in the plate is discussed when the B-G wave and the material parameter change along the length direction in the half-space of the functionally graded voltage-voltage magnetic field. The non-uniform distribution of the material can be obtained from this method. Qualitatively changing the propagation characteristics of waves, The results show that the B-G wave propagating on the surface of the functionally graded voltage-voltage magnetic material is a dispersive wave when the parameters of the material vary with the same exponential law, if the piezoelectric damage results in the uneven distribution of the material parameters along the length of the plate. So the thick-torsion wave in some frequency range will show an energy trapping phenomenon, and the energy will be concentrated in a certain region of the piezoelectric plate. These phenomena will not occur when the material is uniformly distributed. Finally, By using the approximate equation of Tiersten HF and Fourier series, by changing the cross section of the resonator and the thickness of the additional mass layer in the quartz crystal microbalance, The inertia of the additional mass layer plays a leading role in the vibration frequency. The vibration is mainly concentrated in the thicker region of the device. If the device is designed to be a thin shape with a thick middle edge, This study reveals the physical mechanism of the influence of weak interface, functionally graded material and non-uniform thickness on the wave propagation characteristics. It has important theoretical and guiding significance for the analysis and design of piezoelectric composite devices and the measurement of specific experimental data.
【學(xué)位授予單位】：西安交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN384
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本文編號(hào)：1612445