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.
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。
表1：MIG焊接参数
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.
参考文献
[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).
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中厚板不开坡口的焊接工艺 摘要：中厚板的埋弧自动焊可以采用I型坡口和X型坡口等型式，通过对焊接试板的焊接工艺性能分析以及焊接填充材料用量的分析，说明I型坡口焊接可减少焊接残余变形，节省填充材料，提高劳动效率。 在目前的一些容器和钢结构工程中，中厚板的焊接采用埋弧自动焊的方法。坡口型式可采用I型和X型两种。对于中厚板，坡口直接影响焊缝的截面积及焊接应力的分布，在板厚相同的情况下，坡口尺寸越大(包括间隙和角度)，收缩变形越大，必然会增加焊接成本和拖延施工进度。因此，坡口型式及尺寸的选择是相当重要的，除符合有关国标及设计要求外，还需满足坡口加工及施焊要求。 结合某炼钢工程钢结构制作的实际情况，对中厚板的对接焊缝进行了焊接工艺性能分析与选择，通过工艺试验评定，满足了焊缝的质量要求。 1焊接工艺参数 （1）试板一，钢板厚度为δ=32 mm，Q345C，开X型坡口。（背面碳弧气刨清根）。钢板的尺寸及接头形式简图见图1，焊接工艺参数见表1。
焊接层数为5层，焊接时间为657 s，加上层间清理焊剂、药皮的时间，焊接试板所需时间大致为40 min（经过多次焊接的平均时间）。 （2）试板二，钢板厚度为δ=32mm，Q345C，开I型坡口。钢板的尺寸及接头形式简图见图2，焊接工艺参数见表2。
焊层为2层，焊接时间为355 s，加上清理焊剂、药皮的时间，焊接试板所需时间大致为15 min（经过多次焊接的平均时间）。 采用I型坡口的焊接方法，背面无需碳弧气刨清根。因此大大缩短了施焊时间，加快了施工进度。此外，由于焊接层数少，焊剂的用量也会相对减少。 2无损检测 试板一Ⅰ级合格（检测标准为GB11345），试板二Ⅰ级合格（检测标准为 GB11345）试板一熔合比小，熔深和余高也较小。焊接残余变形小，焊丝用量较小。 3焊接接头的力学性能分析 对焊接接头力学性能试验数据的分析，可直接反映焊接工艺参数的选择对厚板焊接的影响。对于上述两个试板，分别取拉伸试验件2件，侧弯试验件4件，冲击6件（焊缝、热影响区各3件）。 试板一的力学性能见表3，试板二的力学性能见表4。由表3、表4可知，二者的力学性能均符合要求。
中英文对照外文翻译 汽车变速器设计 我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。因此，我们希望发动机总是在最好的状态下工作。但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。为什么减速可以增扭，而增速又要减扭呢？设发动机输出的功率不变，功率可以表示为 N = w T，其中w是转动的角速度，T 是扭距。当N固定的时候，w与T是成反比的。所以增速必减扭，减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比，也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器，它的传动比分别是：1档3.704:１；2档2.202:1；3档1.414:1；4档1:1；5档（超速档）0.802:1。 当汽车启动司机选择1档时，拨叉将1/2档同步器向后接合1档
齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上（红色箭头）。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈，输出轴转1圈。 当汽车增速司机选择2档时，拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1，输入轴转2.2圈，输出轴转1圈，比1档转速增加，扭矩降低。 当汽车加油增速司机选择3档时，拨叉使1/2档同步器回到空档位置，又使3/4档同步器移动直至将3档齿轮锁定在输出轴上，使动力可以从轴入轴—中间轴—输出轴上的3档变速齿轮，通过3档变速齿轮带动输出轴。典型3档传动比是1.7:1，输入轴转1.7圈，输出轴转1圈，是进一步的增速。 当汽车加油增速司机选择4档时，拨叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合，动力直接从输入轴传递到输出轴，此时传动比1:1，即输出轴与输入轴转速一样。由于动力不经中间轴，又称直接档，该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃油经济性。 换档时要先进入空档，变速器处于空档时变速齿轮没有锁定在输出轴上，它们不能带动输出轴转动，没有动力输出。 一般汽车手动变速器传动比主要分上述1－4档，通常设计者首先确定最低（1档）与最高（4档）传动比后，中间各档传动比一
附录A Lathe fixture design and analysis Ma Feiyue (School of Mechanical Engineering, Hefei, Anhui Hefei 230022, China) Abstract: From the start the main types of lathe fixture, fixture on the flower disc and angle iron clamp lathe was introduced, and on the basis of analysis of a lathe fixture design points. Keywords: lathe fixture; design; points Lathe for machining parts on the rotating surface, such as the outer cylinder, inner cylinder and so on. Parts in the processing, the fixture can be installed in the lathe with rotary machine with main primary uranium movement. However, in order to expand the use of lathe, the work piece can also be installed in the lathe of the pallet, tool mounted on the spindle. THE MAIN TYPES OF LATHE FIXTURE Installed on the lathe spindle on the lathe fixture
专业资料 学院： 专业：土木工程 姓名： 学号： 外文出处：Structural Systems to resist (用外文写) Lateral loads 附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 抗侧向荷载的结构体系 常用的结构体系 若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。 这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。 如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类： 1.抗弯矩框架。 2.支撑框架，包括偏心支撑框架。 3.剪力墙，包括钢板剪力墙。 4.筒中框架。 5.筒中筒结构。 6.核心交互结构。 7. 框格体系或束筒体系。 特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。 将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并
不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。 虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。 抗弯矩框架 抗弯矩框架也许是低，中高度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。 我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。 支撑框架 支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。
中国地质大学长城学院 本科毕业设计外文资料翻译 系别：工程技术系 专业：机械制造设计及其自动化 姓名：李旭 学号： 05211501 2015年 4 月 2 日
英文翻译原文: (一)镗削加工和镗床 像车床加工零件一样，镗床能在中空的工件或由钻削加工或其它工艺所加工的孔上进行内轮廓圆的加工。镗削是由那些类似车削的刀具完成的。因为镗头必须达到镗杆的全长，刀具将发生弯曲，因此，尺寸精度的保持性成为了一个重大问题。 镗杆必须有足够的刚度——刀杆是由较高弹性模量的材料制造的，比如碳化钨（硬质合金）——去减小弯曲和避免摇动和振动。镗杆被设计有减振的能力。 镗床既能加工在车床上加工的较小工件，镗铣床又能加工巨大的工件。这类机械既有立式的又有卧式的并且能够完成如：车削、车端面、切槽、和倒角。一台立式的镗床类似一台车床，但它有一根垂直的工件旋转轴。 刀具（通常用于切削的单独切削点是由M-2和M-3高速钢和C-8硬质合金制造的）被安装于能垂直运动（用于镗削和车削）和径向运动（用于车端面）并由十字导轨导向的刀头上。刀头能够旋转去加工圆锥形表面。 在卧式镗床上工件被装夹在能在水平面内两个轴向和径向上移动的工作台上，刀具被安装于能做垂直和纵向两方向上运动的主轴箱上。钻头、铰刀、螺纹刀和铣刀都能安装于机床主轴上。 镗床具有许多优良的性能，它所加工工件的直径是1m-4m(3ft-12ft)，工件尺寸达到20m(60ft)的可在专用的立式镗床上加工。机床功率范围可达到150kw(200hp)。这些可用于所有运动都能编程的数字控制加工。利用这些控制，只需要很少的相关操作，并且稳定性和生产率大大提高了。镗床的切削速度和进给速度和车床比较相似。 坐标镗床是属于具有较高精度支撑的立式镗床。尽管它们可用于各类尺寸的工件加工和拥有夹紧合安装的刀具空间。它们正被多功能的数控机床取代。 镗床的设计要求：导轨的效率，类似于车削的经济型操作，另外，应该考虑以下因素： a.无论何时，应尽可能注意是加工通孔而并盲孔。（盲孔系列是指那些没有穿国工件厚度的孔） b.应该控制径向进给速率，很难去支撑径向，因为切削力引起镗杆的弯曲变形。 c.应该避免交叉的内表面加工。
翻译部分 英文原文 Gear mechanisms Gear mechanisms are used for transmitting motion and power from one shaft to another by means of the positive contact of successively engaging teeth. In about 2,600B.C., Chinese are known to have used a chariot incorporating a complex series of gears like those illustrated in Fig.2.7. Aristotle, in the fourth century B .C .wrote of gears as if they were commonplace. In the fifteenth century A.D., Leonardo da Vinci designed a multitude of devices incorporating many kinds of gears. In comparison with belt and chain drives ,gear drives are more compact ,can operate at high speeds, and can be used where precise timing is desired. The transmission efficiency of gears is as high as 98 percent. On the other hand, gears are usually more costly and require more attention to lubrication, cleanliness, shaft alignment, etc., and usually operate in a closed case with provision for proper lubrication. Gear mechanisms can be divided into planar gear mechanisms and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and power between parallel shafts ,and spatial gear mechanisms between nonparallel shafts. Types of gears (1)Spur gears. The spur gear has a cylindrical pitch surface and has straight teeth parallel to its axis as shown in Fig. 2.8. They are used to transmit motion and power between parallel shafts. The tooth surfaces of spur gears contact on a straight line parallel to the axes of gears. This implies that tooth profiles go into and out of contact along the whole facewidth at the same time. This will therefore result in the sudden loading and sudden unloading on teeth as profiles go into and out of contact. As aresult, vibration and noise are produced. (2)Helical gears. These gears have their tooth elements at an angle or helix to the axis of the gear(Fig.2.9). The tooth surfaces of two engaging helical gears inn planar gear mechanisms contact on a straight line inclined to the axes of the gears. The length of the contact line changes gradually from zero to maximum and then from maximum to zero. The loading and unloading of the teeth become gradual and smooth. Helical gears may be used to transmit motion and power between parallel shafts[Fig. 2.9(a)]or shafts at an angle to each other[Fig. 2.9(d)]. A herringbone gear [Fig. 2.9(c)] is equivalent to a right-hand and a left-hand helical gear placed side by side. Because
毕业设计 外文翻译 题目曲轴的加工工艺及夹具设计学院航海学院 专业轮机工程 学生佟宝诚 学号 10960123 指导教师彭中波 重庆交通大学 2014年
Proceedings of IMECE2008 2008 ASME International Mechanical Engineering Congress and Exposition October 31-November 6, 2008, Boston, Massachusetts, USA IMECE2008-67447 MULTI-OBJECTIVE SYSTEM OPTIMIZATION OF ENGINE CRANKSHAFTS USING AN INTEGRATION APPROACH Albert Albers/IPEK Institute of Product Development University of Karlsruhe Germany Noel Leon/CIDyT Center for Innovation andDesign Monterrey Institute of Technology,Mexico Humberto Aguayo/CIDyT Center forInnovation and Design, Monterrey Institute ofTechnology, Mexico Thomas Maier/IPEK Institute of Product Development University of Karlsruhe Germany ABSTRACT The ever increasing computer capabilities allow faster analysis in the field of Computer Aided Design and Engineering (CAD & CAE). CAD and CAE systems are currently used in Parametric and Structural Optimization to find optimal topologies and shapes of given parts under certain conditions. This paper describes a general strategy to optimize the balance of a crankshaft, using CAD and CAE software integrated with Genetic Algorithms (GAs) via programming in Java. An introduction to the groundings of this strategy is made among different tools used for its implementation. The analyzed crankshaft is modeled in commercial parametric 3D CAD software. CAD is used for evaluating the fitness function (the balance) and to make geometric modifications. CAE is used for evaluating dynamic restrictions (the eigenfrequencies). A Java interface is programmed to link the CAD model to the CAE software and to the genetic algorithms. In order to make geometry modifications to
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施工组织设计的重要性 摘要： 建筑工程在施工过程中，施工组织方案的优劣不仅直接影响工程的质量，对工期及施工过程中的人员安全也有重要影响。施工组织是项目建设和指导工程施工的重要技术经济文件。能调节施工中人员、机器、原料、环境、工艺、设备、土建、安装、管理、生产等矛盾,要对施工组织设计进行监督和控制,才能科学合理的保证工程项目高质量、低成本、少耗能的完成。 关键词： 项目管理施工组织方案重要性 施工组织设计就是对工程建设项目整个施工过程的构思设想和具体安排，是施工组织管理工作的核心和灵魂。其目的是使工程速度快、质量好、效益高。使整个工程在施工中获得相对的最优效果。 1.编制施工组织设计重要性的原因 建筑工程及其施工具有固定性与流动性、多样性与单件性、形体庞大与施工周期长这三对特点。所以，每一建筑工程的施工都必须进行施工组织设计。这是因为：其它一般工业产品的生产都有着自己固定的、长期适用的工厂。而建筑施工具有流动性的特点，不可能建立这样的工厂，只能是当每一个建筑工程施工时，建立一个相应的、临时性的，如同工厂作用性质的施工现场准备，即工地。施工单件性特点与施工流动性特点，决定了每一建筑工程施工都要选择相应的机具和劳动力组织。选择施工方法、拟定施工技术方案及其劳动力组织和机具配置，统称为施工作业能力配置。施工周期的特点，决定了各种劳动力、机具和众多材料物资技术的供应时间也比较长，这就产生了与施工总进度计划相适应的物资技术的施工组织设计内容。由此可见，施工组织设计在项目管理中是相当重要的。 2.施工组织设计方案的重要性 建筑产品作为一种商品，在项目管理中工程质量在整个施工过程中起着极其重要的作用。工程建设项目的施工组织设计与其工程造价有着密切的关系。施工组织设计基本的内容有：工程概况和施工条件的分析、施工方案、施工工艺、施工进度计划、施工总平面图。还有经济分析和施工准备工作计划。其中,施工方案及施工工艺的确定更为重要,如:施工机械的选择、水平运输方法的选择、土方的施工方法及主体结构的施工方法和施工工艺的选择等等,均直接影响着工程预算价格的变化。在保证工程质量和满足业主使用要求及工期要求的前提下,优化施工方案及施工工艺是控制投资和降低工程项目造价的重要措施和手段。 2.1施工组织方案在很大程度上影响着工程质量，因此合理的施工组织方案 不仅是确保工程顺利完成的基础，也是工程安全的依据。施工组织设计是建筑工程设计文件的重要组成部分，是编制工程投资概预算的主要依据和编制招投标文件的
中国地质大学长城学院本科毕业设计外文资料翻译 系别：工程技术系 专业：机械设计制造及其自动化 姓名：路双铭 学号： 05211623 2015 年 4 月 1 日
Shapers, Drilling and Milling Machines A shapers utilizes a single-point tool on a tool holder mounted on the end of the ram. Cutting is generally done on the forward stroke. The tool is lifted slightly by the clapper box to prevent excessive drag across the work, which is fed under the tool during the return stroke in preparation for the next cut. The column houses the operating mechanisms of the shaper and also serves as a mounting unit for the work-supporting table. The table can be moved in two directions mutually perpendicular to the ram. The tool slide is used to control the depth of cut and is manually fed. It can be rotated through 90 deg, on either side of its normal vertical position, which allows feeding the tool at an angle to the surface of the table. Two types of driving mechanisms for shapers are a modified Whitworth quick-return mechanism and a hydraulic drive. For the Whitworth mechanism, the motor drives the bull gear, which drives a crank arm with an adjustable crank pin to control the length of stroke. As the bull gear rotates, the rocker arm is forced to reciprocate, imparting this motion to the shaper ram. The motor on a hydraulic shaper is used only to drive the hydraulic pump. The remainder of the shaper motions are controlled by the direction of the flow of the hydraulic oil. The cutting stroke of the mechanically driven shaper uses 220 deg. Of rotation of the bull gear, while the return stroke uses 140 deg. This gives a cutting stroke to return stroke ratio of 1.6 to 1. The velocity diagram for a hydraulic shaper shows that for most of the tool during cutting stroke is never constant, while the velocity diagram for a hydraulic shaper shows that for most of the cutting stroke the cutting speed is constant. The hydraulic shaper has an added advantage of infinitely variable cutting speeds. The principal disadvantage of this type of machine is the lack of a definite limit at the end of the ram stroke, which may allow a few thousandths of an inch variation in stroke length. A duplicating device that makes possible the reproduction of contours from a sheet-metal template is available. The sheet metal template is used in conjunction with hydraulic control. Upright drilling machines or drill presses are available in a variety of sizes and types, and are equipped with a sufficient range of apindle speeds and automatic feeds to fit the neds of most industries. Speed ranges on a typical machine are from 76 to 2025 rpm., with drill feed from 0.002 to 0.020 in.per revolution of the spindle. Radial drilling machines are used to drill workpieces that are too large or
钢结构中厚板的焊接技术 从20世纪80年代以来，中国建筑钢结构得到了空前的发展，建筑钢结构在国民经济建设中占有非常重要的地位。钢结构由于自身的诸多优点，包括自重轻、建设周期短、适应性强、造型美观、维护方便等，其应用越来越广泛。钢结构的发展与钢产量紧密相关。我国已经成为世界产钢大国，2006年中国生产钢已达4.1亿t，其中钢结构的产量高达1.4亿t，能源、交通、冶金、机械、化工、电力、建筑及基础设施建设等领域的钢结构产业已成为国民经济建设的支柱。我国轻钢钢结构、空间钢结构、高层钢结构、桥梁钢结构和住宅钢结构等工业与民用建筑，如雨后春笋般涌现，遍布全国。 与此同时，建筑钢结构中厚钢板得到越来越大量的使用，如北京新保利大厦工程使用的轧制H型钢翼板厚度达到125mm（ASTMA913Gr60），国家体育场（鸟巢）工程用钢最大板厚达110mm（Q460E-Z35），大量钢结构工程采用厚钢板，促进了厚钢板焊接技术的发展，同时也丰富了建筑用钢的范围。 厚板焊接 厚板、超厚板焊接时填充焊材熔敷金属量大，焊接时间长，热输入总量高，构件施焊时焊缝拘束度高、焊接残余应力大，焊后应力和变形大。焊接施焊过程中，易产生热裂纹与冷裂纹。
厚板在焊接前，钢板的板温较低，在开始焊时，电弧的温度高达1250～1300℃，厚板在板温冷热骤变的情况下，温度分布不均匀，使得焊缝热影响区容易产生淬硬——马氏体组织，焊缝金属变脆，产生冷裂纹的倾向增大，为避免此类情况发生，厚板焊前必须进行加热。 在实际生产制造过程中，应对焊接过程进行控制，以防止焊接裂纹的产生。 1. 定位焊：定位焊是厚板施工过程中最容易出现问题的部位。由于厚板在定位焊时，定位焊处的温度被周围的“冷却介质”很快冷却，造成局部过大的应力集中，引起裂纹的产生，对材质造成损坏。解决的措施是厚板在定位焊时，提高预加热温度，加大定位焊缝长度和焊脚尺寸。 2. 多层多道焊：在厚板焊接过程中，坚持的一个重要的工艺原则是多层多道焊，严禁摆宽道。这是因为厚板焊缝的坡口较大，单道焊缝无法填满截面内的坡口，摆宽道焊接造成的结果是，母材对焊缝拘束应力大，焊缝强度相对较弱，容易引起焊缝开裂或延迟裂纹的发生。而多层多道焊有利的一面是：前一道焊缝对后一道焊缝来说是一个“预热”的过程；后一道焊缝对前一道焊缝相当于一个“后热处理”的过
英文原文： SHAFT AND GEAR DESIGN Abstract: The important position of the wheel gear and shaft can' t falter in traditional machine and modern machines. The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, useding for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many ways Key words : Wheel gear ; Shaft In the force analysis of spur gears, the forces are assumed to act in a single plane .We shall study gears in which the forces have three dimensions.The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid. The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side byside on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft,the hand of the gears should be selected so as to produce the minimum thrust load Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power There is on difference between a crossed heli cal gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is , a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm