反应釜毕业设计外文翻译

Welding Simulation of Cast Aluminium A356

X-T. Pham*, P. Gougeon and F-O. Gagnon

Aluminium Technology Centre, National Research Council Canada Chicoutimi, Quebec, Canada

Abstract

Welding of cast aluminium hollow parts is a new promising technical trend for structural assemblies. However, big gap between components, weld porosity, large distortion and risk for hot cracking need to be dealt with. In this paper, the MIG welding of aluminium A356 cast square tubes is studied. The distortion of the welded tubes was predicted by numerical simulations. A good agreement between experimental and numerical results was obtained.

Introduction

Aluminium structures become more and more popular in industries thanks to their light weights, especially in the automotive manufacturing industry. Moreover, welding of cast aluminium hollow parts is a new promising technical trend for structural assemblies [1-3]. However, it may be very challenging due to many problems such as big gap between components, weld porosity, large distortion and risk for hot cracking [4,5]. Due to local heating, complex thermal stresses occur during welding; residual stress and distortion result after welding. In this paper, the aluminium A356 cast tube MIG welding is studied. The software Sysweld [6] was used for welding simulations. The objective is to validate the capability of this software in predicting the distortion of the welded tubes in the presence of large gaps. In this work, the porosity of welds was checked after welding using the X-ray technique. The heat source parameters were identified based on the weld cross-sections and welding parameters. Full 3D thermal metallurgical mechanical simulations were performed. The distortions predicted by the numerical simulations were compared to experimental results measured after welding by a CMM machine.

Experiments

Experimental setup

Two square tubes are made of A356 by sand casting and then machined. They are assembled by four MIG welds, named W1 to W4. Their dimensions and the welding configuration are depicted in Figure 1. Both small (inner) and large (outer) tubes are well positioned on a fixture using v-blocks as shown in Figure 2. The dimensions of the tubes make a peripheral gap of 1 mm between them. This fixture is fixed on a positioner that allows the welding process to be carried out always in the horizontal position. The length of each weld is of 35 mm. The Fronius welding head, which is mounted on a Motoman robot, was used for the MIG welding process. Table 1 indicates the parameters of the welding process for

this welding configuration.

a)

b)

Figure 1: Tube welding configuration: a) cross-section view, b) tube dimensions

Figure 2: Experimental setup for tube welding

Testing

The porosity of welds was observed before and after welding using the X-ray technique to check the quality of these welds according to the standard ASTM E155. The whole welded tubes were then tested by traction on a MTS testing machine. The final dimensions of the welded tubes are measured on a CMM machine at many points on the tubes. The distortion of the welded tubes is determined by comparing the final positions with the initial positions of the tubes.

Numerical analysis

In Sysweld, a welding analysis is performed based on a weak-coupling formulation between the heat transfer and mechanical problems. Only the thermal history will affect on the mechanical properties, but not in reverse direction. Therefore, a thermal metallurgical mechanical analysis is divided into two steps. The first step is a thermal metallurgical analysis, in which the heat transferred from the welding source makes phase changes during the welding process. The results of temperature and phase changes from the first step are then used as input for the second analysis. It is a pure thermo-elasto-plastic simulation [6].

Heat source model identification

Before running a welding simulation, it is necessary to determine the parameters of the heat source model. This is called heat source fitting. Actually, it is a thermal simulation using this heat source model in the steady state, which iscombined with an optimization tool to obtain the parameters of the heat source. Figure 3 presents the form of a 3D conical heat source of which the energy distribution is described in Eq (1) as follows:

F=Q0exp(-r2/r02) (1)

in which Q0 denotes the power density; and r，r0 are defined by

r2=(x-x0)2+(x-x0-v t)2(2)

and

r0=r e-(r e-r i)(z e-z+z0)/(z e-z i) (3)

where（x0,y0,z0)is the origin of the local coordinate system of the heat source; r e and r i the radius of the heat source at the positions z e and z i,respectively;v the welding speed and t the time.

In this study, a metallographic cross-section has been used to identify the heat source parameters as shown in Figure 4. The use of a 3D conical heat source fits very well the weld cross-section. The mesh size in the cross-section is around 0.5 mm for this case. The finer is the mesh, the more accurate is the shape of the melting pool, but the longer is the simulation.

Figure 3: 3D conical heat source (Sysweld).

a)

b)

Figure 4: (a) Metallographic cross-section, (b) Melting pool cross-section.

Analysis model

The mesh of the tubes was created in Hypermesh 7.0. Sysweld 2007 has been used as solver and pre/post processor. A full 3D thermal metallurgical mechanical analysis with brick and prism elements. Two welding sequences have been done such as W1/W2/W3/W4 and W1/W3/W2/W4. The tubes are clamped using four v-blocks during the welding, two for each tube. In the simulations, the positions where the tubes are in contact against the surfaces of the v-blocks are considered as fixed conditions (i.e. Ux = Uy = Uz = 0). In the release phase, the tubes are free from the v-blocks.

Results

The distortion of the welded tube is measured when it is released from the constraints. The distortion is determined by measuring the displacement of the small tube on the top and

lateral surfaces along the centre line of the tube. These measures are relative to the large tube. Figures 5a-b depict the distortion predicted by the numerical simulations of the sequence W1/W2/W3/W4 and W1/W3/2/W4, respectively. Good agreements between experimental and numerical results were obtained in the two welding sequences as indicated in Tables 2-3, in both the distortion tendency and distortion range of the process variation.

a)

b)

Figure 5: Tube distortion (Norm U): (a) Sequence W1/W2/W3/W4, (b) Sequence W1/W3/W2/W4.

Table 2: Distortion result comparison (welding sequence W1/W2/W3/W4)

a)

b)

Figure 7: State of stresses Sxy (a) Clamped, (b) Released. (Red = positive, Blue = negative)

a)

b)

Figure 8: State of stresses Sxz (a) Clamped, (b) Released. (Red = positive, Blue = negative) Figures 6-8 shows the state of the stresses of the welded tubes at room temperature for the sequence W1/W2/W3/W4 after welding when clampled and released from constraints (x is the direction along the axe of the welded tube). To show how the welded tube is distorted, positive-negative values are used instead of the true values of stresses. The distortion of the welded tube can be explained as the new equilibrium position due to the residual stresses when there is no external load. It is remarked that in the presence of large gaps, the distortion of the welded tube is very likely in the rotational mode around local welds.

Conclusions

The MIG welding is very good for assembling aluminium cast tubes (hollow parts) in the presence of large gaps.

The 3D thermal metallurgical mechanical simulation of the cast tube welding using Sysweld has been validated. A very good agreement between numerical and experimental results was obtained for both the distortion tendency and distortion range.

The welding sequence has a major influence on the distortion of the welded structure. It turns out that the optimization of the welding sequences for a reasonable distortion of a welded structure with a large number of welds becomes very important.

Acknowledgments

The authors would like to thank gratefully Rio Tinto Alcan and General Motor for financial and technical supports, particularly Martin Fortier and Pei-Chung Wang. Also, the authors are grateful to Welding Team at ATC (Audrey Boily, Martin Larouche, Fran?ois Nadeau and Mario Patry) for experimental works.

References

1. K-H. Von Zengen, Aluminium in future cars – A challenge for materials science, Materials Science Forum, 519-521 (Part 2), 1201-1208 (2006).

2. S. Wiesner S., M. Rethmeier and H. Wohlfart, MIG and laser welding of aluminium alloy pressure die cast parts with wrought profiles, Welding International, 19 (2), 130-133 (2005).

3. R. Akhter, L. Ivanchev, C.V.Rooyen, P. Kazadi and H.P. Burger, Laser welding of SSM Cast A356 aluminium alloy processed with CSIR-Rheo technology, Solid State Phenomena, 116-117, 173-176 (2006).

4. J.F. Lancaster, Metallurgy of welding, Abington Publishing (1999).

5. Φ. Grong, Metallurgical modelling of welding, The institute of materials (1997).

6. Sysweld, Sysweld reference manual, ESI Group (2005).

译文

铸造A356铝合金的焊接模拟

X-T. Pham*, P. Gougeon and F-O. Gagnon

Aluminium Technology Centre, National Research Council Canada Chicoutimi, Quebec, Canada

摘要：

空心铝铸造件的焊接是一个很有前途的新结构组件技术的趋势。然而，组件之间的差距较大，焊接孔隙度，大变形和热裂需要处理的风险。在这篇文章中，对铸造A356铝合金的方管的MIG焊接进行了研究。并对焊接管弯曲变形进行了数值模拟预测。实验结果和数值模拟结果的相似度很高。

1前言：

由于铝合金结构自身的重量轻，所以它变得越来越流行，尤其是在汽车制造业。此外，空心铝铸造件的焊接是一种新的有前途的结构组件技术的趋势[1-3]。但是它可能有很大的挑战，由于大的差距，例如组件之间，焊接孔隙度，大变形和热裂的危险等很多问题[4,5]。由于局部加热，复杂的热应力发生在焊接中；焊后会出现残余应力和变形的结果。在这篇文章中，关于铸造A356铝合金的方管的MIG焊接进行了研究。Sysweld软件[6]被用于焊接模拟。其目的是验证这个软件在大差距的焊接管扭曲变形的预测中的能力。在这项工作中，在焊接后利用X射线技术来检查焊缝的孔隙率。在热源参数的基础上，确定了焊缝截面和焊接参数。冶金力学的3D热量模拟已经被使用。用数值模拟所预测出来的扭曲值与焊后用CCM机器所测量的实验结果进行了比较。

2实验：

2.1实验方案

两个成直角的管子是用A356通过砂型铸造然后在加工形成的。他们是由四个管MIG焊接组装而成，命名为W1至W4。他们的尺寸和焊接配置描绘如图1.不论小还是大的管子都很好的定位在一个采用V形块的夹具上，如图2所示。管子的规模使它们之间产生了一个1毫米厚的不主要的缝隙。这个夹具固定在一个定位上，使焊接过程中总是保持水平位置。每个焊缝的长度是35毫米。被安装在Motoman机器人上的Fronius 焊头是用于MIG焊过程中的。表1表明了这个焊接结构的焊接工艺参数。

a)

b)

图1：钢管焊接配置:a）截面图 b）钢管尺寸

图2：管焊接实验装置

2.2测试

焊接前后利用X射线技术观察焊缝气孔，按ASTM E155标准检查这些焊缝质量。

然后整个焊接管子通过一个MTS试验机上的牵引来测试。焊接管最终的尺寸被定位在管子上的多个点的CMM机器所测量。扭曲的焊接管的最终位置与初始位置的管子进行比较。

3数值分析

在Sysweld软件中，焊接分析是基于热传导和力学问题之间的微弱链接而制定的。只有热学经历在相同方向上才将影响力学性能。因此，热学冶金力学分析分为两个步骤。第一步是一种热学冶金分析，其中在焊接过程的相变过程中从焊接电源的热量被转移。第一步温度和相变的结果将作为第二次的分析。它是一个纯热弹塑性模拟[6]。

4热源模型的鉴定

焊接模拟运行之前，有必要确定热源模型的参数。这就是所谓的热源配件。实际上，它是一种热模拟中的稳定状态，在这种稳定状态中用一种优化工具来获得的热量来源的参数。图3给出了一个三维锥形热源形式，它的能量分布在方程中描述：举例如下:

F=Q0exp(-r2/r02) (1)

其中Q0表示功率密度; r，r0被定义为：

r2=(x-x0)2+(x-x0-v t)2(2)

和

r0=r e-(r e-r i)(z e-z+z0)/(z e-z i) (3)

其中（x0,y0,z0)是局部坐标系原点热源，r e和r i在位置z e和z i,分别为半径热源；v为焊接速度，t为时间。

在这项研究中，金相截面已被用来确定热源，如图4所示的参数。一个三维锥形热源使用非常适合的焊接横截面。在横截面的网状尺寸是这种情况下约为0.5毫米。越细的网状，越是更准确的熔池形状，但不再是模拟。

图3:三维锥形热源 (Sysweld).

a)

b)

图4: (a) 金相截面(b) 熔池截面

5模型分析

在Hypermesh7.0上创建了管网。Sysweld2007已被用来作为求解器和前后处理器。一个完整的三维热学冶金力学分析用砖和棱镜为元素。两种焊接序列已完成，如W1/W2/W3/W4和W1/W3/W2/W4。在焊接过程中，夹住管子的过程中使用四个V形块，每个管子两个。在模拟中，管子的立场是反对接触的V形块的表面被认为是固定的条件（如Ux = Uy = Uz = 0）。在释放阶段，管子在V形块中是不受力的。

6结果

当焊接管子从束缚状态被释放时，它的变形被控制。失真是通过测量沿管子的中心线从顶部到两侧面的小管的位移。这些措施是相对于大管的。图5a,b的描述失真通过数值模拟预测序列为W1/W2/W3/W4和W1/W3/W2/W4。在数值计算结果和实验中获得了良好的协议的两种焊接顺序如表2-3所示，在这两种倾向的扭曲和变形的过程中变化的范围。

a)

b)

图5：电子管失真（标准U）：（a）序列W1/W2/W3/W4，（b）序列W1/W3/W2/W4 表2：扭曲结果的比较（焊接顺序W1/W2/W3/W4）

表2：畸变结果比较（焊接顺序W1/W2/W3/W4）

a)

b)

图6：规定压力Sxx （a）夹紧（b）放松（红=正，蓝=负）

a)

b)

图7：规定压力Sxy （a）夹紧（b）放松（红=正，蓝=负）

a)

b)

图8：规定压力Sxz （a）夹紧（b）放松（红=正，蓝=负）

图6-8显示了在夹紧和放松后的焊接在室温的规定压力下焊接序列W1/W2/W3/W4的状态（x是沿焊接管斧头方向）。以展示焊管失真，正负值来代替真实的应力值。该焊管失真可以解释为新的平衡位置，由于残余应力在没有外部负载的情况下。这就是说，在存在较大的差距时，在很大程度上对焊管失真是围绕当地的焊缝旋转模式进行的。

7结论

MIG焊接很好的解决了铝铸造管（中空部分）存在非常大的差距的问题。

三维热学冶金铸造力学焊接管采用Sysweld模拟已验证。模拟值与实验结果在扭曲趋势和变形范围内非常吻合。

焊接的序列对焊接结构变形产生重大影响。事实证明，优化的焊接顺序对一个具有大量的焊缝的扭曲焊接结构的合理性非常重要。

致谢

The authors would like to thank gratefully Rio Tinto Alcan and General Motor for financial and technical supports, particularly Martin Fortier and Pei-Chung Wang. Also, the authors are grateful to Welding Team at ATC (Audrey Boily, Martin Larouche, Fran?ois Nadeau and Mario Patry) for experimental works.

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附录1：外文资料翻译 A1.1外文资料题目 26.22 接地故障电路开关 我们目前为止报道的接地方法通常是充分的, 但更加进一步的安全措施在某些情况下是必要的。假设例如, 有人将他的手指伸进灯口（如Fig.26.45示）。虽然金属封入物安全地接地, 但那人仍将受到痛苦的震动。或假设1个120V 的电炉掉入游泳池。发热设备和联络装置将导致电流流入在水池中的危害，即使电路的外壳被安全地接地，现在已经发展为当这样的事件发生时，设备的电源将被切断。如果接地电流超过5mA ，接地开关将在5 ms 内跳掉，这些装置怎么运行的？ 如Fig.26.46所示，一台小变流器缠绕上导线 ，第二步是要连接到可能触发开合120 V 线的一台敏感电子探测器。 在正常情况下流过导体的电流W I 与中性点上的电流N I 准切的相等，因此流经核心的净潮流(N W I I -)是零。 结果，在核心没有产生电流，导致的电压F E 为零，并且开关CB 没有动作。 假设如果某人接触了一个终端(图Fig.26.45示)，故障电流F I 将直接地从载电线漏到地面，这是可能发生的。如果绝缘材料在马达和它的地面封入物之间断开，故障电流也会被产生。在以下任何情况下，流经CT 的孔的净潮流等于F I 或L I ，不再是零。电流被产生，并且产生了可以控制CB 开关的电压F E 。 由于5 mA 不平衡状态只必须被检测出，变压器的核心一定是非常有渗透性的在低通量密度。 Supermalloy 是最为常用的，因为它有相对渗透性典型地70000在通量密度仅4mT 。 26.23 t I 2是导体迅速发热的因素 它有时发生于导体短期内电流远大于正常值的情况下，R I 2损失非常大并且导体的温度可以在数秒内上升几百度。例如，当发生严重短路时，在保险丝或开关作用之前，会有很大的电流流过导体和电缆。 此外，热量没有时间被消散到周围，因此导体的温度非常迅速地增加。 在这些情况下什么是温度上升？ 假设导体有大量m ，电阻R 和热量热容量c 。 而且，假设电流是I ，并且那它流动在t 少于15秒期间。 在导体上引起的热 Rt I Q 2= 从Eq.3.17，在功率一定的情况下我们可以计算导体上升的温度差：

毕业设计外文翻译附原文

外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华

外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文

应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。

机械类毕业设计外文翻译

本科毕业论文(设计) 外文翻译 学院：机电工程学院 专业：机械工程及自动化 姓名：高峰 指导教师：李延胜 2011年05 月10日 教育部办公厅 Failure Analysis，Dimensional Determination And

Analysis，Applications Of Cams INTRODUCTION It is absolutely essential that a design engineer know how and why parts fail so that reliable machines that require minimum maintenance can be designed．Sometimes a failure can be serious，such as when a tire blows out on an automobile traveling at high speed．On the other hand，a failure may be no more than a nuisance．An example is the loosening of the radiator hose in an automobile cooling system．The consequence of this latter failure is usually the loss of some radiator coolant，a condition that is readily detected and corrected．The type of load a part absorbs is just as significant as the magnitude．Generally speaking，dynamic loads with direction reversals cause greater difficulty than static loads，and therefore，fatigue strength must be considered．Another concern is whether the material is ductile or brittle．For example，brittle materials are considered to be unacceptable where fatigue is involved． Many people mistakingly interpret the word failure to mean the actual breakage of a part．However，a design engineer must consider a broader understanding of what appreciable deformation occurs．A ductile material，however will deform a large amount prior to rupture．Excessive deformation，without fracture，may cause a machine to fail because the deformed part interferes with a moving second part．Therefore，a part fails(even if it has not physically broken)whenever it no longer fulfills its required function．Sometimes failure may be due to abnormal friction or vibration between two mating parts．Failure also may be due to a phenomenon called creep，which is the plastic flow of a material under load at elevated temperatures．In addition，the actual shape of a part may be responsible for failure．For example，stress concentrations due to sudden changes in contour must be taken into account．Evaluation of stress considerations is especially important when there are dynamic loads with direction reversals and the material is not very ductile． In general，the design engineer must consider all possible modes of failure，which include the following． ——Stress ——Deformation ——Wear ——Corrosion ——Vibration ——Environmental damage ——Loosening of fastening devices

STC89C52处理芯片-毕业论文外文翻译

中文翻译 STC89C52处理芯片 电气工程的研究和解决方案中心（ceers） 艾哈迈德为吉.波特 首要性能： 与MCS-51单片机产物兼容、8K字节在系统可编程视频存储器、1000次擦拭周期，全静态操作：0Hz~33Hz、三级加密程序存储器，32个可编程I/O接口线、三个16位定时器（计数器），八个中断源、低功能耗空闲和掉电模式、掉电后间断可唤醒，看门狗定时器、双数值指针，掉电标示符。 关键词：单片机，UART串行通道，掉电标示符等 前言 可以说，二十世纪跨越了三个“点”的时代，即电气时代，电子时代和现已进入的电脑时代。不过，这种电脑，通常指的是个人计算机，简称PC机。还有就是把智能赋予各种机械的单片机（亦称微控制器）。顾名思义，这种计算机的最小系统只用了一片集成电路，即可进行简单的运算可控制。因为它体积小，通常都是藏在被控机械的内部里面。它在整个装置中，起着有如人类头脑的作用，他出了毛病，整个装置就会瘫痪。现在，单片机的种类和适用领域已经十分广泛，如智能仪表、实施工控、通讯设备、导航系统、家用电器等。各种产品一旦用上了单片机，就你能起到产品升级换代的功效，常在产品名称前冠以形容词——“智能型”，如智能洗衣机等。接下来就是关于国产STC89C52单片机的一些基本参数。 功能特性描述: STC89C52单片机是一种低功耗、高性能CMOS8位微控制器，具有8K在系统可编程视频播放存贮器使用高密度非易失性存储器技术制造，与工业80C51 产物指令和引脚完全兼容。片上反射速度允许程序存储器在系统可编程，也适用于常规的程序编写器。在其单芯片上，拥有灵敏小巧的八位中央处理器和在线系统可编程反射，这些使用上STC89C52微控制器为众多嵌入式的控制应用系统提供高度矫捷的、更加有用的解决方案。STC89C52微控制器具有以下的标准功效：8K字节的反射速度，256字节的随机存取储存器，32位I/O串口线，看门狗定时器，2个数值指针，三个16 为定时器、计数器，一个6向量2级间断结构，片内晶振及钟表电路。另外，STC89C52可降至0HZ静态逻辑操作，支持两种软件可选择节电模式、间断继续工作。空闲模式下，CPU停止工作，允许RAM、定时器/计数器、串口、间断继续工作。掉电保护体式格局下，RAM内容被生成，振动器被冻结，单片机一切的工作停止，直到下一个间断或者硬件复位为止。8位微型控制器8K字节在系统中可编程FlashSTC89C52.。

本科毕业设计方案外文翻译范本

I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]

基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也

毕业设计外文翻译原文.

Optimum blank design of an automobile sub-frame Jong-Yop Kim a ,Naksoo Kim a,*,Man-Sung Huh b a Department of Mechanical Engineering,Sogang University,Shinsu-dong 1,Mapo-ku,Seoul 121-742,South Korea b Hwa-shin Corporation,Young-chun,Kyung-buk,770-140,South Korea Received 17July 1998 Abstract A roll-back method is proposed to predict the optimum initial blank shape in the sheet metal forming process.The method takes the difference between the ?nal deformed shape and the target contour shape into account.Based on the method,a computer program composed of a blank design module,an FE-analysis program and a mesh generation module is developed.The roll-back method is applied to the drawing of a square cup with the ˉange of uniform size around its periphery,to con?rm its validity.Good agreement is recognized between the numerical results and the published results for initial blank shape and thickness strain distribution.The optimum blank shapes for two parts of an automobile sub-frame are designed.Both the thickness distribution and the level of punch load are improved with the designed blank.Also,the method is applied to design the weld line in a tailor-welded blank.It is concluded that the roll-back method is an effective and convenient method for an optimum blank shape design.#2000Elsevier Science S.A.All rights reserved. Keywords:Blank design;Sheet metal forming;Finite element method;Roll-back method

机械类毕业设计外文文献翻译

沈阳工业大学工程学院 毕业设计（论文）外文翻译 毕业设计（论文）题目：工具盒盖注塑模具设计 外文题目：Friction , Lubrication of Bearing 译文题目：轴承的摩擦与润滑 系（部）：机械系 专业班级：机械设计制造及其自动化0801 学生姓名：王宝帅 指导教师：魏晓波 2010年10 月15 日

外文文献原文： Friction , Lubrication of Bearing In many of the problem thus far , the student has been asked to disregard or neglect friction . Actually , friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement. Friction is harmful or valuable depending upon where it occurs. friction is necessary for fastening devices such as screws and rivets which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary. The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also , greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pressure builds up because made from low temperature materials may melt. There are three types of friction which must be overcome in moving parts: (1)starting, (2)sliding, and(3)rolling. Starting friction is the friction between two solids that tend to resist movement. When two parts are at a state of rest, the surface irregularities of both parts tend to interlock and form a wedging action. To produce motion in these parts, the wedge-shaped peaks and valleys of the stationary surfaces must be made to slide out and over each other. The rougher the two surfaces, the greater is starting friction resulting from their movement . Since there is usually no fixed pattern between the peaks and valleys of two mating parts, the irregularities do not interlock once the parts are in motion but slide over each other. The friction of the two surfaces is known as sliding friction. As shown in figure ,starting friction is always greater than sliding friction . Rolling friction occurs when roller devces are subjected to tremendous stress which cause the parts to change shape or deform. Under these conditions, the material in front of a roller tends to pile up and forces the object to roll slightly uphill. This changing of shape , known as deformation, causes a movement of molecules. As a result ,heat is produced from the added energy required to keep the parts turning and overcome friction. The friction caused by the wedging action of surface irregularities can be overcome

毕业设计外文翻译

毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年

研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.wendangku.net/doc/4c12632801.html,，niuzhiguo@https://www.wendangku.net/doc/4c12632801.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.wendangku.net/doc/4c12632801.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。

电气毕业设计外文文献

外文文献： The Intelligent Building One of the benefits of the rapid evolution of information technology has been the development of systems that can measure, evaluate, and respond to change。An enhanced ability to control change has sparked developments in the way we design our physical environment, in particular, the buildings in which we work。As a result, we are witnessing significant growth in the area of "Intelligent Buildings"--buildings that incorporate information technology and communication systems, making them more comfortable, secure, productive, and cost-effective What is an Intelligent Building? An Intelligent Building is one equipped with the telecommunications infrastructure that enables it to continuously respond and adapt to changing conditions, allowing for a more efficient use of resources and increasing the comfort and security of its occupants。An Intelligent Building provides these benefits through automated control systems such as: heating, ventilation, and air-conditioning (HVAC)；fire safety；security；and energy/lighting management。For example, in the case of a fire, the fire alarm communicates with the security system to unlock the doors。The security system communicates with the HVAC system to regulate the flow of air to prevent the fire from spreading。 What benefits do Intelligent Buildings offer their owners and occupants? The introduction in the workplace of computers printers photocopiers, and fax machines has increased indoor pollution。Electrical and telecommunications facilities in office buildings are under pressure to satisfy the demands created by the rapid growth of computer and networking technologies。These factors have a definite impact on productivity. New technology can be used to create Intelligent Buildings that address these problems by providing a healthier, more productive, and less energy-intensive work environment。As these are critical factors for business