计算单元

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。

This kind of model is more precise than ever for calculating physical parameters in flow unit. In a well bore, there are six methods to recognize a flow unit.

首次采用地质条件约束下的测井解释方法，建立了流动单元识别的测井解释模型，准确地计算出了流动单元储层物性参数。

By using Visual Basic, based on NASTRAN finite element analysis, this paper developed an efficient and convenient software which can process automatically the result of NASTRAN analysis and establish the database, and compute the failure probability of structural element and system, plot the contour of failure probability.

在NASTRAN有限元分析结果的基础上，以Windows95为开发平台，以VisualBasic为开发工具，开发了一个效率高，使用方便的结构可靠性分析软件该软件可以自动处理NASTRAN的计算结果，建立数据库，计算结构单元和系统的失效概率，绘制结构失效概率分布云图等，为工程人员在有限元计算的基础上进一步进行可靠性分析提供了一个方便、快捷的工具

These issues mainly include simulation offlexible soil container, selection of dynamic constitution model of soil, simulation of the changing-status non-linearity on soil-structure interface, meshing, treatment of reinforcements in structure,using of symmetry principle and so on.

按照本文的建模原则和计算方法，对土-桩基-结构相互作用体系振动台试验进行三维有限元计算分析，计算中土体采用等效线性模型，利用面-面接触单元考虑土体与结构交界面的状态非线性。

By applying one couple of unit force on two suspension centers based on 3D FEM to calculate their relative displacement, coefficient of torsion displacement, the radial gate s torsional rigidity coefficient is derived; and its stress distribution is analyzed to solve radial gate s torsion problem.

基于空间有限单元法，对闸门吊点施加1对单位力计算出2个吊点的相对位移———闸门扭转挠度系数，进而推算出闸门抗扭刚度系数和单位位移下的应力状态，据此最终解决弧门的扭转问题。并通过某一工程实例的分析计算，表明该方法在生产设计中具有较好的实用性，可以有效地解决弧形闸门的扭转计算问题

Slipper type universal coupling"s fork joint and palm end are the weak parts of the main transmission system. In this article, the two parts" intensity values are obtained through finite element analysis . After making three-dimensional computer simulation analysis by ANSYS, the results show that the middle arc of the fork joint in loaded side and the intersection of fork bore and the arc are the danger location, where the stress is largest and stress concentration is serious.

本文对轧机主传动系统机械部分的薄弱部件进行强度计算，即对滑块式万向联轴器的主要零部件的强度进行有限元分析，通过ANSYS有限元分析软件进行三维计算机仿真，由计算结果可知，在叉头受载侧过渡圆弧段中部、叉头镗孔与过渡圆弧交接处这两个部位的应力最大且存在严重的应力集中，考虑到单元总数限制及计算时间等因素，整体模型的网格划分较疏，不能反映倒圆角等细节。

The results of computation show that this method is very effective for reducing and controlling the transverse oscillation of wave motion and for the calculation of wave particle velocity of wave motion on free surface, w...

计算表明：这种0—1混合型边界元的剖分方式，在控制和减缓波浪"横向振动"幅度及水面单元水质点波动速度的计算方面，显示出了其独到的优越和灵活之处，为时域内的波浪非线性变形计算提供了时步上的数值保证

The results of computation show that this method is very effective for reducing and controlling the transverse oscillation of wave motion and for the calculation of wave particle velocity of wave motion on free surface, w...

计算表明：这种0—1混合型边界元的剖分方式，在控制和减缓波浪&横向振动&幅度及水面单元水质点波动速度的计算方面，显示出了其独到的优越和灵活之处，为时域内的波浪非线性变形计算提供了时步上的数值保证

On the basic assumption of WENCAL,using pre parameter method,the equation calculating multi element beam of different section and elasticity modulus on different groundsill are given in this paper. The programming language is QBASIC.

依据文克尔基本假定，利用初参数法推导出不同地基及不同地基梁截面弹性模量的多单元弹性地基梁计算公式，并用已编制的 QBASIC语言计算程序，通过实例计算，结果正确、合理。

On the basic assumption of WENCAL,using pre-param eter method,the equation calculating multi-element beam of different section and ela sticity modulus on different groundsill are given in this paper.The programming language is QBASIC.The results of example show that the calculation is correct and reasonable.

文摘：依据文克尔基本假定，利用初参数法推导出不同地基及不同地基梁截面弹性模量的多单元弹性地基梁计算公式，并用已编制的QBASIC语言计算程序，通过实例计算，结果正确、合理。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。