查询词典 fem

This method overcome the problems of many supposition conditions in theory and difficulty in searching critical slip surface in 3D limiting equilibrium analysis; It uses the 3D FEM\'s stress field directly, differs from the practical value of 3D FEM strength reduction method used hypothesized load, and differs from the characteristic of the FEM with limiting equilibrium theory still to need to divide the columniation, and suppose the critical slip surface in advance.

该方法克服了三维极限平衡分析方法在理论上引入较多假设条件，且搜索临界滑裂面困难的问题；它直接采用三维有限元应力场，不同于三维有限元强度折减法基于虚拟荷载上得出的实用价值；同时异于沿用极限平衡理论的有限元法仍需要进行条柱划分，并事先假设滑裂面形状及位置的缺点。

The main problems researched in the dissertation and achievements are as follows: The dissertation explains the science background and the theoretical and actual meaning of the task. The progress and the problems of the flow imaging technique are briefly explained. The advantages of electrical capacitance tomography are discussed. The paper discusses the formation and operating principle of ECT, and builds up the definite mathematical model by detail theoretical analyse, and establishes the Finite Element Model of the system by changing the finite boundary value problem of ECT into equivalence variation problem according to variation principle. On the basis of the FEM of the system, the paper builds the finite element model of the capacitance sensitivity field distribution and programs its finite element simulation software and proves the validity of the FEM of the ECT from different aspects. With the FEM and the qualitative analyse of the effect of each structural parameter of the capacitance transducer on its capability, this paper optimizes the structural parameters of the capacitance transducer, and obviously improves its capability. The compare of the simulated result with the static experimental result shows that the error of them is less than 0.9%.

其主要研究内容包括：阐述课题研究的学术背景及其理论与实际意义，概括总结出流动层析成像技术的发展现状和存在的问题，指出电容层析成像技术的优点；讨论电容层析成像系统的组成及工作原理，进行详尽的理论分析，以变分原理为基础，将ECT的有限元边值问题转换为等价的变分问题，从而建立系统的有限元模型；在系统有限元模型的基础上，建立敏感场的数学模型，编制有限元的仿真软件，并从不同角度证明电容层析成像系统有限元模型的正确性；利用有限元模型，定性地分析电容传感器各结构参数对其性能的影响，并对传感器结构参数进行优化设计，使其性能得到明显的改善。8电极ECT系统的仿真和静态实验结果的比较表明，它们之间的相对误差小于0。

Aim at the efficiency and precision of the stochastic FEM, two kind of new stochastic FEM are put forward and the correlative theories and methods are established:1 The stochastic FEM based on Gauss integral methodEstablish the method of Stochastic FEM based on the Legendre integration.

本论文针对如何提高非线性结构随机有限元计算精度和效率，提出了两种新的随机有限元法，建立了相应的理论和方法，具体如下： 1、Gauss类积分随机有限元方法建立了基于Legendre积分的随机有限元方法。

Secondly, based on general FEM theory, this paper has discussed FEM of matchboard cement concrete pavements with and without joints and explained three-dimensional FEM of cement concrete pavements.

2根据一般有限单元法理论，探讨了有无接缝的企口板砼路面有限元分析方法，以及三维混凝土路面的有限元分析方法。

And presents some commonly process and attentions in applying the FEM software ANSYS to PCM analysis.2 Analyzed the PCM performances under the affection of piezoelectric and polymer"s material characteristic by FEM, and got the rule.3 Analyzed the PCM performances which affected by stickup layer"s materials characteristic and its thickness under the application of FEM.4 Based on the construction principles of 1-3 type orthotropic piezoelectric composite materials, the finite element model is designed and its orthotropy is analyzed, at the same time, the length/broad ratio to PCM orthotropy is also analyzed.

二、应用有限元法分析了压电相材料和聚合物基体相材料特性对于压电复合材料综合性能的影响规律。三、应用有限元法分析了粘贴层的材料性质和厚度尺寸对压电复合材料在实际应用中性能的影响规律。四、根据提出的正交异性压电复合材料的构造原理，设计出1-3型正交异性压电复合材料的有限元模型并分析其正交异性，同时分析了压电相材料长宽比对其正交异性的影响。

In this paper, we use FEM software ANSYS to simulate. Using FEM to evaluate the strength of pressure hull, the FEM model of outer covering and stiffeners can use shell element to establish, but it may waste much computing time to calculate. Therefore, in this paper, we can evaluate more easier by making use of the idea of effective-width, and considering the stiffener/plating combined moment of inertia.

本文采用有限元素分析软体ANSYS进行求解，在有限元素分析的模拟上，外壳与环肋均可用壳元素建立一实体模型来分析，但是在模型的建立上过於复杂，在解析上也需要更多的时间来计算，因此本文采用有效幅度的观念，考虑环肋与壳板间之组合惯性矩，将环肋部分取梁元素来模拟，如此一来可简化建立模型的困难度，且大大的缩短分析的时间。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

On the basis of above research works, a finite element model for column of the TH6350 high speed numerical control boring was built; the stiffness of the slide guide interface between the bed and column bottom and the constrain stiffness from lead screw were estimated by using experimental formula, to guarantee the rationality of the boundary condition of the FEM model; the week link of the column has been found by application of ANSYS software to FEM model analysis of the column, The result shows that the calculation data and test data are very consistent, therefore proved the properness of the FEM model.

在上述工作基础上，本文对TH6350高速数控镗床的立柱进行了有限元建模；并利用经验公式估算了立柱与床身之间的导轨结合面上的刚度和丝杠副约束刚度，保证了有限元模型的边界条件的合理性；应用ANSYS软件进行有限元模态分析找到了立柱结构的薄弱环节，通过分析对比表明有限元分析计算与现场测试的结果相一致，证明了有限元模型的正确性，为立柱结构的进一步改进设计和优化提供了重要参考依据。

In this thesis, the application of FEM in the special cars frames has been studiedIn the chapter 1 of this thesis, the basic principle of FEM is introduced, and the application of FEM in static and dynamic analysis of a car frame is discussed briefly, considering its structure and load properties.

本文结合工程实例，对特种车车架的有限元静力、动力分析作了一些探讨。本文第一章介绍了有限元法的基本思想，并结合汽车车架的具体结构和载荷特点，对利用有限元法进行静力、动力分析的有关问题进行了阐述。

After the failure in solving the energy equation by using Galerkin FEM and upwinding FEM, the lumping upwind FEM developed by professor Jianhang Wu was employed to obtain temperature solution.

在求解能量方程时，在实践了使用伽辽金有限元，迎风有限元求解失败后，采用吴江航教授提出的集中质量迎风有限元，得出了温度解。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。