有限元法

Objective: To study the displacement and intra-stress distribution of degenerate lumbar disc during rotation manipulation by using 3D finite element system,so as to explore the mechanism of action,safety and rationality of manipulation.

目的：用三维有限元法，分析施行坐位腰椎旋转手法时退变腰椎单元的内在应力及位移分布的特点，以探讨手法的作用机制、安全性及其合理性。

As an example, a central cracked plate with pulse uniaxial tension was used to demostrate the initiation and the processes of the stable crack growth.

有限元法是求其数值解的一个有效的方法，它已被用来求裂纹扩展前的应力、应变场〔，'。

New ideas and methods in the paper:1 The formulas on perforated casing collapse strength were deducted, which offereda convenient method to analyze the relationship between casing collapse strength and perforation;2 The stress and displacement formulas on the system of casing, cement anddeformation under the non-uniform load were deducted, which offered the theoretical found for designing optimally casing string;3 The relationship between structure in-situ field of whole oil field and casing failurewere studied, which offered the scheme for the prediction of casing failure. The process of study in the paper:1 For simulating the relationship between the structure in-situ field and the casingfailure in the oil-deformation, the tests of the uniaxial tensile, compress, tnaxial compress and dilatability were made on the samples of the drill cores from deformation of casing failure position in Yuejing II oil field.

本文的主要创新： 1推导出了射孔套管抗挤强度的解析式，为分析射孔与套管强度的变化关系提供了简便的方法； 2推导出了非均匀地层载荷作用下套管、水泥环和地层组合体的应力和位移解析式，并非均匀作用下套管柱优化设计提供了理论依据； 3研究整个油田区块构造应力场与套管损坏关系，为预测套管损坏提供了可行方案；本文的研究过程如下： 1为模拟构造应力场与油层段套管损坏关系，做了大量的岩石单轴抗拉、单轴抗压、三轴试验以及岩石遇水膨胀试验，获得了研究区块岩石的弹性模量、泊松比、内聚力、内摩擦角以及岩石的线膨胀系数，这此数据为本文研究油层段套管损坏机理研究的理论分析和有限元法提供了实验数据。

Third, it can not solve the exterior Dirichlet problem.

另外，有限元法不能解决Dirichlet外问题。

The basic theory of extended finite element method are expounded particularly, and given a class of enrichment displacement functions---the exponent discontinuous function which is presented to simulate the discontinuous character resulted from discontinuity such as crack.

本文详细阐述了扩展有限元法的基本原理，提出一类附加位移形函数-指数型间断函数来描述由裂纹所导致的位移不连续规律。

XFEM;the exponent discontinuous function;crack

扩展有限元法；指数间断函数；裂纹

The primary objective of this study is to analyze the buckling mode of inclined lipped purlins and predict distortional buckling strengths, as compared to the consequence calculated by ANSYS.

本文以此作为出发点，对卷边檩条的弹性屈曲进行了理论分析，并应用ANSYS有限元法计算总结了斜卷边檩条翼缘屈曲系数的合理取值方法。

In this study, the technology of 3D finite element was applied, and the purpose of this study is meant to guide the clinical use of distractor.

本研究试图通过有限元法，了解影响种植牵张初期生物力学环境的多种因素，为种植牵张临床提供生物力学方面的理论依据。

The Finite Element Method is used to implement the numerical simulation on the model, and the rule of temperature distribution and the relations between screw deformation and temperature are obtained.

应用有限元法(Finite Element Method， FEM)对该模型进行数值模拟，得到滚珠丝杠传动过程中的温度场的分布规律以及温度对丝杠变形的影响关系。

With the narrow bandwidth of microstrip antenna, a microstrip antenna with the substrates of double negative media is designed by the software HFSS which is based on finite element method.

针对微带天线带宽较窄的问题，采用基于有限元法的HFSS软件，设计1种以双负材料为衬底的微带天线。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。