自动力

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。

In this paper we investigate the dynamical properties of continuous mapson a class of hereditarily decomposable chainable continua and the structure ofthe inverse limit space using a piecewise monotone continuous map with zerotopological entropy on a finite graph as a single bonding map.

本文研究了一类遗传可分可链连续统上连续自映射的动力性质并且对有限图上逐段单调且具有零拓扑熵的连续自映射的逆极限空间的拓扑结构进行了较为细致的刻画。

In such an environment, some despair, some people and some people a heavy drinker and some people ...... So there is no life without passion is not the dream of power, then muddle along day by day, a appear every day, never see the beauty of the world, no less than olfactory floral cooler.

在这样的环境中，有的人悲观失望、有的人自怨自艾、有的人仰天长叹、有的人借酒浇愁……于是生活没有了激情没有了动力没有了梦想，从此一天天得过且过，一天天垂头丧气，再也看不到世间的美丽，再也嗅不到清凉的花香。

Front-end floating pneumatic power chuck, with combined functions of self-centering clamp and floating compensation clamp, is used for machining of pipe end.

前置式气动浮动动力卡盘是集自定心夹紧和浮动补偿式夹紧二功能于一身，用于管道的端头加工，加工笔直管道时，使用自定心夹紧功能；加工的管道若有弯曲变形或加工弯管端头时，则采用定心卡盘辅助定心，用本卡盘的浮动夹紧功能夹紧管子后，退开定心卡盘再加工管子端头。

After studying the curve of the vibration frequencies, which are varying with the changing of the structural parameters such as the rigidity of pier, the rigidity of straining beam, the rigidity of truss, the high of pier, the width of deck, and so on, some rules about the changing of vibration frequencies and the influencing of the structure that vary with the parameters were achieved.

研究了桥墩刚度、横系梁刚度、桁架片刚度、桥墩高度、桥面宽度等参数对结构动力特性的影响，通过对结构的自振振型及频率进行相应分析，得出结构参数变化对结构的横向刚度、竖向刚度、纵向刚度和扭转刚度及其他动力特性的影响程度及规律。

In this paper we study mainly the topological structures of some invariant sets and entropy of continuous self-maps on Warsaw circle and unstable mainifold s and entropy of continuous self-maps on a tree.

本文主要研究了华沙圈上连续自映射的一些不变集的拓扑结构、拓扑熵和树上连续自映射的非稳定流形和拓扑熵等某些动力性质。

In this paper we study mainly the topological structures of some invariant sets and entropy of continuous self-maps on Warsaw circle and unstable mainifolds and entropy of continuous self-maps on a tree.

中文摘要：本文主要研究了华沙圈上连续自映射的一些不变集的拓扑结构、拓扑熵和树上连续自映射的非稳定流形和拓扑熵等某些动力性质。

A model of trashrack is established for Guanyinyan Hydropower Station and the strength computation is based on the 3D dynamic FEM for the construction.

建立了观音岩电站拦污栅结构模型，基于三维动力有限元法对其进行抗震分析，计算得到结构的5阶自振特性，根据文献[1]规定的振型分解反应谱法以及动静结合的方法对结构进行动力分析，对结构的抗震安全性能作出评价，并指出了抗震薄弱部位。

It's uncertain what powerplant will be used but previously Russian Automotive Design has built several custom Cayennes in the past and most of these kept their standard powertrains.

这是不确定的是什么动力，但将使用以前俄罗斯汽车设计建立了一些自定义Cayennes在过去，大多数这些保持其标准动力。

Starting on October 1, 1999, cargo motor tricars with licenses for road transportation must have their power installation removed before being permitted to ride on the roads designated by the public security traffic administrative department of public security.

自1999年10月1日起，持有道路运输许可证件的动力装置的货运三轮车，必须拆除动力装置后，方能在公安交通管理部门规定的道路上行驶。

For a big chunk of credit-card losses; the number of filings (and thus charge-off rates) would be rising again, whether

年美国个人破产法的一个改动使得破产登记急速下降，而后引起了信用卡大规模的亏损。

Eph. 4:23 And that you be renewed in the spirit of your mind

弗四23 而在你们心思的灵里得以更新