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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。

Results show that:(1) For each particle size of andalusite, variation tendency of the properties of the material is generally the same: the maximum of bulk density, compressive strength and rupture strength appears in the range of 5%-10% content of fiber, these properties of the material remarkably decrease as the fiber content exceed 10%; while at the same fiber content, the properties of the material increase with the increase of firing temperature.

结果表明：(1)对于不同粒度的原料，性能变化规律大致相同：在同一烧成温度下，体积密度、常温耐压强度、常温抗折强度在5％～10％之间出现峰值，加入量超过10％之后材料的性能明显下降；在相同的纤维含量下，随着烧成温度的提高，试样的各项性能均有所上升。

At present international admiral is in measure of 1 ～ 100nm inside exceed small grain and its compact aggregation, and the material that by accept Mi Weijing makes is appellative material of the rice that it is accept, its include a variety of pulverous material such as metal, metalloid, organic, inorganic and biology.

目前国际上将处于1～100nm尺度内的超微颗粒及其致密的聚集体，以及由纳米微晶所构成的材料通称为纳米材料，其包括金属、非金属、有机、无机和生物等多种粉末材料。

The tests and studies on the rhyolite filtering material show that the functions of the rhyolite material are superior to that of the arenaceous quartz, and the rhyolite flitering material is worth further studying and developing.

对流纹岩滤料的初步试验研究表明，流纹岩滤料的性能明显优于石英砂，是比较理想的天然无机滤料，具有进一步研究开发价值。

The informational object authoring and distribution system provides a set of software modules that the manufacturers can use to author, maintain and distribute Material Safety Data Sheets and their customers, as members of the system of Value-Added Material Safety Data Sheets, can use to retrieve, maintain and distribute the Material Safety Data Sheets.

所述信息对象编辑和分配系统提供了一组软件模块，厂商可以使用这些模块来编辑、维护和分配材料安全数据表，并且他们的客户作为增值材料安全数据表的系统成员可以使用这些模块来检索、维护以及分配材料安全数据表。

The change that turn over cloth with soft nap is vamp material, and replace bootlace to also begin to leave in popularity of Euramerican each country character with retractility material come, and the application of all sorts of new material such as polyurethane flexibility fiber is trend of a kind of trend.

反绒革为鞋面材料，以及以伸缩性材质取代鞋带也开始在欧美各国流行开来，而聚氨酯弹性纤维等各种新材料的应用则是一种潮流趋势。

The germination, expansion and reciprocity of the crack inside the material embody on the crystal bound of the material. So, in this study we can change the bourgeon and extend condition of the tiny crack inside the material by design and control the crystal interface structure effectively and provide new research approach for the design and manufacture of the machinability ceramic.

由于材料的破坏和加工都决定于材料内部微裂纹生成的难易程度和扩展程度，而材料内部裂纹的萌发、扩展和相互作用集中表现在材料的晶界和相界面上；因此，本研究通过有效的设计和控制界面结构，改变材料内部微裂纹的萌生和扩展条件，为可加工陶瓷的设计和制备提供新的研究途径。

The model provides a dynamic material plan decision-making model, in view of material distribution, material shipment time, and suppliers capacity decision factors for inventory level and service level influence.

模型提供一个动态物料规划决策模型，针对营运总部在物料分配高低，物料运送时间长短，供应商群的产能是否满足与稳定等决策因子，对供应链存货水准与服务水准所产生的影响。

In order to reduce production cost of ceramal friction material,the cost optimization solution for Cu-base ceramal friction material is introduced,and the effect of the optimization solution on performance of the friction material is studied.

为降低金属陶瓷摩擦材料的制造成本，介绍了Cu基金属陶瓷摩擦材料成本优化方案，并研究了优化方案对Cu基金属陶瓷摩擦材料性能的影响。

There are shovel blades equipped bottom of the cinquefoil shelf. When shovel blades rotate with rollers, they throw up the materials and send them into the space between rollers and ring and then form a material bed. The material bed produces centripetal force as a result of rotating of roller. The material is crushed by the centripetal force.

磨辊吊架下装有铲刀系统，其位置处于磨辊下端，铲刀与磨辊同转过程中把物料抛起喂入磨辊与磨环之间，形成垫料层，该料层受磨辊旋转产生向外的离心力碾压，达到制粉目的。

I can not negligent, he should do what?

我不能不在意了，他要做什么呢？

It is very dangerous to swim in the river alone.

一个人到河里游泳是很危险的。