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1.
An analytical sandwich beam model for piezoelectric bender elements is derived based on the first-order shear deformation theory （FSDT）, which assumes a single rotation angle for the whole cross-section and a quadratic distribution for coupled electric potential in piezoelectric layers. Shear coefficient is introduced to correct the effect of transverse shear strain on shear force and the electric displacement integration. Static and free vibration analyses of simply-supported bender elements are carried out for the sensor function. The results illustrate the high accuracy of the present model compared with the exact 2D solutions. 相似文献
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采用偶应力理论对单层压电悬臂梁式微执行器在强外加电场作用下的非线性静态特征进行了研究.悬臂式执行器包括压电层、被动（弹性）层和2个电极层.首先,采用瑞利-里兹方法分析了在强外加电场作用下由于压电层电致伸缩效应引起的执行器非线性静态特性.其次,由于悬臂执行器的厚度在μm量级,存在变形尺度效应,采用偶应力理论对变形的尺度效应进行了分析.分析结果表明：悬臂执行器的非线性随着外加电场强度的增大而增大,当外加电场很大时,出现刚度软化现象;而且,执行器被动层和压电层厚度比的最优值不是通常采用的1.0.在微尺度下,由于微梁变形存在尺度效应,该厚度比的最优值应比1.0大. 相似文献
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魏胜 《深圳职业技术学院学报》2012,11(3):7-12
研究了双层压电悬臂梁的工作原理及其有效机电耦合系数,借助ANSYS软件并选用Solid5（压电材料）,Solid45（中间金属层）,Circu94（电阻）3种元素类型建立压电换能器的有限元模型,通过谐振仿真分别求出压电装置的短路和开路谐振频率,得到其有效机电耦合系数．仿真结果表明,压电装置的有效机电耦合系数要小于压电材料的耦合系数,且与理论计算结果基本一致,仿真方法可有效地评价压电换能器的工作性能,并为后续实验提供理论指导． 相似文献
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INTRODUCTION Piezoelectric bimorphs (or benders), a special type of piezoelectric device, which can produce flexural deformation significantly larger than the length or thickness deformation of the individual piezoelectric layers, have been widely used as elec- troacoustic transducers, medical devices and micro- robot due to their characteristics of easy miniaturiza- tion, high positioning accuracy, sensitive response, and large displacement (e.g., Shirley and Hampton, 1978; Ha and Kim, 2… 相似文献
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黄上恒 《商丘师范学院学报》2000,16(4):36-38
研究了同时处于机械与电学载荷之下的压电陶瓷柱体表面裂纹前缘的应力场和电位移场。求得了应力及电位移的奇异性阶数和相应的两个强度因子。 相似文献
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工程结构中的复合材料层合板的几何参数往往具有随机性质.如何研究随机参数层合板的灵敏度, 并对参数进行优化分析,这对正确估计结构设计的可靠性有着非常重要的意义.本文用随机摄动法,导出了求反对称层合板响应灵敏度的计算公式,研究了随机参数反对称层合板响应的灵敏度和优化设计,并用网格法计算出最佳铺层角. 相似文献
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We made a theoretical study of the carrier distribution and electromechanical fields in a free piezoelectric semiconductor rod of crystals of class 6 mm. Simple analytical expressions for the carrier distribution, electric potential, electric field, electric displacement, mechanical displacement, stress, and strain were obtained from a 1D nonlinear model reduced from the 3D equations for piezoelectric semiconductors. The distribution and fields were found to be either symmetric or antisymmetric about the center of the rod. They are qualitatively the same for electrons and holes. Numerical calculations show that the carrier distribution and the fields are relatively strong near the ends of the rod than in its central part. They are sensitive to the value of the carrier density near the ends of the rod. 相似文献
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INTRODUCTION Recently, more and more investigations have been conducted on multilayer piezoelectric media. Kharouf and Heyliger (1994) and Heyliger and Ra- mirez (2000) dealt with the free vibration problems of laminated piezoelectric cylinders and discs, respec- tively. Chen (2000) considered the free vibration of (multilayer) nonhomogeneous piezoceramic hollow spheres by employing a separation formulation for displacements. Chen (2001) developed a state-space method for free vibration … 相似文献
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在弹性梁与磁弹性力学理论的基础上,应用动力学方法建立电磁场和温度场耦合作用下的载流梁的非线性热磁弹性耦合振动方程。应用Galerkin法导出了系统受电磁力和热力共同作用的非线性振动微分方程组。通过数值计算,给出了不同系统参数下的系统振动的时程图和相图。 相似文献
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何吉欢 《上海大学学报(英文版)》2000,4(1):14-17
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｐｉｅｚｏｅｌｅｃｔｒｉｃｃｅｒａｍｉｃｓｈａｖｅｂｅｅｎｗｉｄｅｌｙｕｓｅｄｉｎｅｎｇｉｎｅｅｒｉｎｇ.ＡｃｏｍｐｒｅｈｅｎｓｉｖｅｌｉｓｔｏｆｗｏｒｋｓｉｎｔｈｉｓａｒｅａｍａｙｂｅｆｏｕｎｄｉｎＲｅｆｓ.[1,2]ａｎｄｔｈｅｒｅｆｅｒｅｎｃｅｓｃｉｔｅｄｔｈｅｒｅｉｎ.Ｉｎｏｒｄｅｒｔｏａｐｐｌｙｔｈｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄｓｔｏｔｈｅｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｔｈｅｐｉｅｚｏｅｌｅｃｔｒｉｃｉｔｙ,ｉｔｉｓｎｅｃｅｓｓａｒｙｔｏｅｓｔ… 相似文献
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INTRODUCTION Piezoelectric symmetric structures always play an important role in the use of piezoelectric materials (Olesiak and Pyryev, 1995; Ding et al., 2003; Wu et al., 2003). To improve the durability of this kind of piezoelectric structures, functionally gradient piezo- electric materials (FGPM) have been developed and used to produce these devices such as sensors and actuators (Hauke et al., 2000; Zhu et al., 1995). For the case when a rectangular plate made of function- ally gr… 相似文献
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沥青路面微波现场热再生传热模型 总被引：1，自引：0，他引：1
为了获得沥青路面微波热再生过程的温度分布规律,根据非稳态导热理论建立了加热区域内的二维传热模型,将加热区域外沥青料简化成4个半无限大固体分别建立了一维传热模型.通过加热水负载实验求解了加热沥青料的辐射电场强度.理论推导出了传热边界条件数学模型,并提出了采用实验数据拟合反求边界条件的方法.通过加热实验测出了沥青混合料的温度并拟合出温度场分布,利用Matlab中的偏微分工具箱对传热模型仿真求解,求得的温度场分布和实验结果相当吻合.研究结果证实了该传热模型具有较高的精度,可以直接计算沥青路面热再生过程中的温度分布. 相似文献
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对利用人工神经网络方法来预测电站锅炉在未知的燃烧或运行工况下烟气中汞组分进行了可行性评估.基于已掌握的三个电站锅炉现场测试的汞排放数据库,建立了一个三层误差反向传播神经网络模型用以对烟囱处汞排放的组分进行预测.全部预测过程包括:数据的采集整理、构建人工神经网络模型、训练过程和误差评估4部分.总共选取了59个煤样、灰样以及电站运行工况参数作为输入变量,利用部分实际汞排放测试数据来指导训练过程,其余的实测数据用来校验网络预测模型的准确性.结果表明,模型获得的预测精度对单质汞元素的均方根误差为0.8μg/Nm3,对全汞的均方根误差为0.9μg/Nm3.这样的误差在当考虑到现场采用半连续释放测量(SCEM)方法,由湿法测试模块所产生的峰值误差时是完全可以接受的. 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＡｓｗｅｋｎｏｗ ,ｔｈｅｃｏｍｐｕｔａｔｉｏｎａｌｐｉｅｚｏｅｌｅｃｔｒｉｃｄｙｎａｍｉｃｅｑｕａｔｉｏｎｓｆｏｒｈｉｇｈｆｒｅｑｕｅｎｃｙａｃｏｕｓｔｉｃｗａｖｅｐｒｏｐａｇａｔｉｏｎｓｗｅｒｅｏｒｉｇｉｎａｌｌｙｅｘｐａｎｄｅｄｆｒｏｍｔｈｅｇｅｎｅｒａｌｃｏｍｐｕｔａｔｉｏｎａｌｓｔｒｕｃｔｕｒａｌｍｅｃｈａｎｉｃｓ,ａｎｄｔｈｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄｓ(ＦＥＭ)ｉｎｉｔｉａｌｌｙｆｒｏｍａｅｒｏｓｐａｃｅａｎｄｃｉｖｉｌｅｎｇｉｎｅｅｒｉｎｇ .Ｔｈｅ… 相似文献
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INTRODUCTION For moderate thickness plate containing notches or holes, neither plane stress nor plane strain theory can describe its true deformation states (Jin and Hwang, 1989). This well known drawback has mo- tivated many analytical and numerical studies carried out to determine the effect of plate thickness on the in-plane stress distribution. Pioneering work on the along depth stress components, i.e. the K-M gener- alized plane strain theory was proposed by Kane and Mindlin (1956)… 相似文献
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This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method (FEM) and plate element method
for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes
and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic
and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods.
The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative
error 0.02%–0.04%) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for
piezoelectric structural analysis due to the assumptions and corrections in the plate theories. The converged Lagrange finite
element methods are compared with the plate element methods and the computed results are in good agreement with available
exact and experimental data. The adaptive Lagrange finite element methods and a new FEA computer program developed for macro-
and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in
this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.
Project supported by SRF for ROCS, SEM of China and partially by Zhejiang Provincial Natural Science Foundation (NSF) of China. 相似文献
18.
Zhou Cheng-ti 《大连大学学报》1991,(1)
本文论述了复合材料的强度和稳定性理论中的三个近代问题:复合材料迭层板的强度准则,多层复合材料圆柱壳的非线性稳定性理论,以及复合材料板的动力稳定性理论。关于迭层板的强度准则,论述了目前以张量多项式形式所表述的唯象性破坏准则,着重讨论和比较了各种近代理论在确定耦合系数方面的特点和差别。提出了近代理论中所存在的困难和发展趋势。在多层复合材料圆柱壳的非线性稳定性理论分析中,主要的问题在于如何研究和考虑那些非线性因素,诸如由材料的剪切模量所引起的物理非线性,横向剪切变形的影响,壳体结构的初始缺陷和几何非线性,以及前屈曲变形和边界支承条件的影响等。本文指出了考虑这些因素的方法以及它们的影响程度。复合材料板的动力屈曲性能研究是一个重要的近代研究方向。本文提出了关于复合材料本身的阻尼系数,纵向和转动惯性力影响,横向剪切效应,迭层板的初始几何缺陷,以及增强纤维的铺设方向等因素对于动力屈曲性能的影响。同时提出了计算这些影响的方法,指出这些因素在复合材料板的动力稳定性分析中有着重要作用。 相似文献
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The functional piezoelectric ceramic smart aggregate(SA) sensors and actuators,based on piezoelectric ceramic materials such as lead zirconium titanate(PZT),were embedded into the reinforced concrete beams with three-point bending under static loading for purposes of damage detection.The SA actuators generated the desired sine sweep excitation signals online and the SA sensors received and detected real-time signals before and after damage.The wavelet analysis and statistical characteristics about damage signals were used as a signal processing and analysis tool to extract the optimal damage information and establish a statistical damage detection algorithm.The damage index-based wavelet analysis and damage probability-based probability and statistics were proposed by PZT wavebased theory and active health monitoring technology.The results showed that the existence of cracks inside largely attenuated the amplitude of active monitoring signal after the damage of beam and the attenuation was related to the severity degree of damage.The innovative statistical algorithm of damage pattern detection based PZT-SA can effectively determine damage probability and damage degree,and provide a prediction for the critical damage location of reinforced concrete structures.The developed method can be utilized for the structural health comprehensive monitoring and damage detection on line of various large-scale concrete structures. 相似文献
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刘翠梅 《商丘师范学院学报》2003,19(5):17-19
根据电磁场理论，由电子注在波导中的辐射过程，推导出由电流所激励的电磁波的辐射功率等于电流对场所作的功，证明了电子流辐射过程中的能量守恒关系，直接由麦克斯韦方程组推导出微波电子器件理论的解析解。 相似文献