查询词典 finit element method

With a 586 computer and ALGOR FEAS software of finite element method, the static stresses of the equalizing bar are obtained by finite element analysis for three finite element models of beam, plate and brick element.

在微机586和ALGOR FEAS有限元软件环境下，对推土机平衡梁以梁、板、块单元为主分别建立了三种有限元模型和进行了有限元应力分析。

The finite element model included two types of main element: beam element for concrete and truss element for internal unbonded or external tendon. The end nodes of main elements were connected with internal constraints named MPC in ABAQUS. Spring elements with very large stiffness were set up at the place of the deviators of externally prestressed beams, or along the span with relatively little space of unbonded internally prestressed beams. The modified Riks method is utilized to trace the entire structural response of beams prestressed with unbonded tendon from zero to ultimate loads. The reliability of the analysis model is verified by analytical results of typical test beams in comparison with experimental ones.

该有限元模型由两类主单元组成，即混凝土梁单元和体内无粘结或体外预应力筋桁架单元；主单元的端部节点用ABAQUS的内在约束MPC连接；在体外预应力梁的转向块处，或沿体内无粘结预应力梁全跨并以比较小的间隔设置刚度足够大的弹簧单元。

The inner force of the line element for underground structure have been calculated using the traditional finite element mesh and high-order manifold method to guarantee the numerical precision of the line element and overcome the disadvantages due to the geometry error between the actual position and computational position of the beam and truss element in common use.

用传统的有限元网格和流形方法的高阶覆盖位移函数来进行地下结构的杆、梁单元计算，保证了线单元模拟的数值精度，同时又克服了常用的杆、梁线单元计算位置与实际位置不相符合从而带来计算误差和结构设计不便等缺点，提供了一种解决结构数值计算的较好的途径。

The revised Hargraves formula has the best result compared with Penman-Monteith formula, the average relative error is 6%, moreover, Hargaves method requiring the least data in calculating ETo, so this method has the high actual application value; The following are Radiation method and Blaney-Criddle method ; The worst is the Pan method, even after revised, the highest and average relative error is 36% and 10%, respectively. So, in this study, Penman-Monteith method, Radiation method, Blaney-Criddle method and Hargraves method are used except Pan method.

在这四种方法中，修正后的Hargraves方法与彭曼—蒙特斯方法的计算结果符合最好，其平均相对误差为6％，而Hargraves方法需要的气象数据只有计算时段的最高、最低温度，该方法具有较高的实际应用价值；辐射方法和布兰尼—克里德尔方法次之；蒸发皿方法最差，即使在修正后，E601型蒸发皿的最大误差也高达36％，平均为10％，所以在预报系统的研究设计中采用了除蒸发皿方法之外的四种方法。

The primary studying works and characteristics:1 To summarize reinforcing theory of cement mixing pile composite foundation2 To analyze the primary mechanics characters and changing rules of cement mixing pile, based on analysis of test data both indoor and outdoor.3 To discuss siding frictional resistance, ending resistance, ultimate bearing capacity of simple mixing pile and effectiveness factor of grouped piles, loading ratio of soil between piles under cushion cap of grouped piles and stress ratio of pile and soil and so on, and use many computation method and experimentation method to ensure bearing capacity of mixing piles composite foundation.4 To point out and analyze eight sides flaws and problems of the bearing capacity calculation method of mixing pile compositefoundation which ensured by national and normative method/ formula.5 To apply test results of loading tests and a few settlement observation data, use gray theory to predicate ultimate bearing capacity of deep mixing piles, actual example demonstrate engaging between theoretical predicted value and actual value.6 To apply groovy layerwise summation method to discuss entity piles method, double foundation method, equivalent layerwise summation method and consolidation theoretical method and so on, especially by combination of engineering example, use FEM to calculate or discuss the settlement and changing rules of composite foundation.7 To discuss problems of critical length of composite foundation by combination of engineering example and numerical analysis method, and analyze the contrast of critical length between simple pile load and most area load of composite foundation, not only critical length of composite foundation is relative to modulus ratio between piles and soil, but also upside load distribution area of composite foundation.

主要的研究工作与特色为：(1)总结了水泥搅拌桩复合地基的加固原理；(2)在对室内外试验资料进行统计分析的基础上，系统分析了搅拌桩水泥土的主要力学特性及其变化规律；(3)探讨了搅拌单桩的侧摩阻力、端阻力、极限承载力及群桩效率系数、群桩承台下桩间土荷载分担比及桩土应力比等，提出用多种计算方法并结合试验方法来综合确定搅拌桩复合地基的承载力；(4)明确指出和分析了按国家有关规范的方法确定搅拌桩复合地基承载力所存在的八个方面的缺陷与问题；(5)利用过去没有加载至破坏阶段的载荷试验成果和较少的沉降观测数据，尝试了用灰色理论预测深层搅拌桩的极限承载力，实例表明理论预测值与实测值吻合较好；(6)在常规分层总和法的基础上，探讨了复合地基沉降计算的实体墩基法、双层地基法、等效作用分层总和法、固结理论法等，特别是结合工程实例，用有限元数值计算等方法计算和讨论了搅拌桩复合地基的沉降及其变化规律；(7)结合工程实例，用数值分析方法探讨了复合地基临界桩长的问题，指出和分析了单桩荷载下的临界桩长与复合地基大面积荷载下的临界桩长存在很大的差别，复合地基的临界桩长不仅与桩土模量比有关，而且与复合地基上部荷载分布面积有关。

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

The approach of computational simulation is the finite element method.The whole research is combined by the following three parts. In part one, a program on quadtree method is compiled. It can automatically generate planar structures with all-quadrangular, good quality elements in high speed, and it can create data files on information of elements and nodes, which provide the foundation for finite element analysis. In part two, a program on finite element calculation is compiled by object-oriented method, During the simulation of fracture, the displacement and stress are calculated by the program.

本文的工作可分为三大部分：第一部分编制了四叉树法程序，通过它可对平面结构进行单元离散，快速自动生成质量较好的全四边形单元，并获得离散后的单元信息和节点信息，为有限元计算打下基础；第二部分利用面向对象方法编制了有限元计算程序，在破坏模拟过程中，利用它进行位移、应力分析；第三部分对脆性材料的破坏过程进行了模拟。

This paper focuses on four important aspects as follows. The first one is the establishment of variational quations which provides the mathematics theories for the finite element method of HMT; the second one is for the study of scalar/node and vector/edge finite element method; the third one is about how to solve faster for the large-sacled matrix system of scalar/node and vector/edge finite element; and the last one is achieving the forward modeling with high precision of HMT method.

主要包括四部分：建立与高频大地电磁法边值问题相等价的变分问题，为有限元数值计算奠定数理基础；标量/矢量有限元方法的研究；加速标量/矢量有限元矩阵系统方程迭代求解技术的研究；实现高频大地电磁参数精确快速正演模拟的研究。

This article mainly simulates gradually damage destruction process of rock, major in determinationg the definition of rock three-dimensional damage tensor, simplify to the damage tensor and obtain its engineering calculation method, and obtains the basic expression form of equivalent stress by equivalent stress assumption, symmetrization to the actual stress, thus obtains construction relation of the festival principle of three-dimensional damage rock mass, finally couples elasticity- plasticity with damage in the finite element equation, with reference to elasticity-plasticity gradually degenerated method thought, simulates rock damage to advance gradually the destruction process in finite element method, draws up elasticity - plasticity and damage coupling two-dimension finite element procedure with the C language in the VC contact surface, by simulating experiment destroyed process, acquires destruction image and the axial load distortion curve of model, agreement with the experimental result.

本文主要模拟岩石渐进损伤破坏过程，确定岩石三维损伤张量的定义，对损伤张量进行简化计算并得出其工程计算方法，采用等效应力假设得出有效应力的基本表达形式，对有效应力进行对称化，得出节理损伤岩体的三维本构关系，在有限元方程中实现弹塑性和损伤耦合；借鉴弹塑性渐进退化方法的思想，采用有限元的方法模拟岩石损伤渐进破坏过程，用C++语言在VC界面编制了弹塑性和损伤耦合的二维有限元程序，通过模拟已有的实验破坏过程，得出模型的破坏图像和轴向荷载变形曲线，与实验结果基本一致。

Derive the requirement to strain and displacement of Patch Test. Give the relationship between weak form of continuity equation and the Patch Test, through which the hybrid element method and quasi-conform element method are analyzed. Refined direct stiffness method and generalized conforming elements are also analyzed about why they can pass patch test. At last, as an example of using the requirement of patch test for displacement, improved the BCIZ Element.

得出分片试验对位移函数和应变函数的要求，这些要求便是一个好的有限元法所应保证的；分析了几何方程弱形式与分片试验的关系，借此分析了杂交元、拟协调元如何满足这些要求，以及在满足这些要求的同时产生的对其他条件的影响；分析了精化直接刚度法、广义协调元和双参数法如何保证分片试验的满足；最后作为位移条件的应用例子，改进了BCIZ元。

A strange and mysterious deep sea creature.

一种奇异、神秘的深海生物。

It's a yellow rectangle .

这是黄色的长方形。