759 自动弯管机及其电气设计(有cad图)
759 自动弯管机及其电气设计(有cad图),759,自动弯管机及其电气设计(有cad图),自动,弯管,及其,电气设计,cad
2011届毕业设计说明书 自动弯管机装置及其电器设计系 、 部: 机械系 学生姓名: 李衍 指导教师: 康煜华 职称 副教授 专 业: 机械制造及其自动化 班 级: 机本0704 完成时间: 2011.6 湖南工学院毕业设计(论文)开题报告 题目自动弯管机装置及其电器设计指导老师康煜华学生姓名李衍班级学号214070437专业机械制造设计及其自动化一、课题的意义现今工业发达,无论是哪一种机器设备、健身器材、家具等几乎都有结构钢管,有导管,用以输油、输气、输液等,而在飞机、汽车及其发动机,健身器材,家具等等占有相当重要的地位。各种管型品种之多、数量之大、形状之复杂,给导管的加工带来了不少的困难。对于许多小企业,家庭作坊,或者大企业中需要配管的场合,如工程机械上的压力油管,机床厂的液压管道发动机的油管健身器材的弯管等等,这些场合可能不需要功能全的弯管机,且加工的管件的难度不高,简易手动型的弯管机很可能适应。这系列弯管机采用手动夹紧,机械弯曲,机器结构简单,控制元件极少,因此价格上比较容易被用户接受。二、课题研究目的和意义市面上现有的自动弯管机大多数是液压的,数控的,也有机械传动的,但它们的占地面积较大(长度在2.54m之间),价格昂贵(25万元人民币或更多),然而大多数用户需求的是占地面积小价格便宜且使用方便的自动弯管机。液压弯管机1-1 数控弯管机1-2本文便是朝这方面的用途面设计的自动弯管机,设计出一种价格和占地面积使用方便的自动弯管机(长0.9M,宽0.8M,高1.1M,价格9000元人民币左右),并着手对弯管机的性能进得进一步的强化,使其能弯曲不同口径或不同的钢型、采用制动电机以提高弯曲机的弯曲精度。大大的简化了电器控制系统,方便操作。三、国内外自动弯管机概述弯管机是我国国防和基础建设的关键设备,为我国的经济发展和国防建设起到了不可估量的作用。弯管机在前期经过了第一步改造,实现了PLC控制、上位计算机监控管理、人机友好界面。但现有的操纵控制系统较为落后,不能很好的满足生产的需要。在此基础上,迫切需要对弯管机进行第二步改造,将整个操作系统改为中频感应加热控制,对弯管机的工作过程实现快速、精确控制以提高弯管机的工作效率和加工精度。 在电力,石油化工等工业和天然气,集中供热等输送工程中,需要大量的弯管,弯头,所以弯管机都作为重要生产设备之一。它的安全、可靠、高效运行,直接关系到白动生产线的生产效率和加工质量。中频加热弯管机具有解热快,氧化少,解热均匀,解热效率高,能保证产品你质量等优点。 弯管机的PLC控制和编程对弯管起着至关重要的作用,它的工作性能对整个控制系统都有着重要的影响,所以研究PLC控制和编程极其重要。 中频加热液压弯管机组采用了先进的计算机网络控制技术,用PLC编程语言及梯形图形进行逻辑控制连接,采用计算机监控系统监视和控制现场设备工作状态,设置工艺参数,下的大工艺命令,整机与其他弯管设备相比:技术含量高,自动化程度先进,控制精度高,能大大的降低生产成本,提高生产率。 控制系统是弯管机的关键组成部分,弯管机的工作性能是系统改造设计的主要目标。弯管机主要由机械装置,液压系统,中频加热系统,PLC控制系统,冷却系统等组成。从系统的观念考虑机械、电气和液压系统之间的匹配问题,得到性能最好的弯管机。我们已经是世界上主要的弯管机生产国家之一,但是目前,管道施工应用的弯管机基本上都是进口的,国外比较著名的弯管机生产厂家有德国的VIETZ公司和美国的CRC公司。通用的技术都是利用静液压传动、气动控制技术来实现弯管机的弯管操作和控制。国内目前仍没有具备生产大型弯管机设计和制造能力的厂家。这主要是国内整体工业化程度不高,国产机械本身的加工精度不够以及专业人才的匮乏,加之国产钢材与进口钢材的差距是导致机械整体质量不高的主要原因。对于弯管机的技术发展有了个基本的了解之后,我们能够更好的发展我国的弯管机行业。四、课题的研究内容、方法、手段与步骤1、研究内容本论文主要是设计出一种价格和占地面积使用方便的自动弯管机(长0.9M,宽0.8M,高1.1M,价格9000元人民币左右),并着手对弯管机的性能进得进一步的强化,使其能弯曲不同口径或不同的钢型、采用制动电机以提高弯曲机的弯曲精度。大大的简化了电器控制系统,方便操作。自动弯管机通用工作流程为: 用起重机将管段放置在弯管机工作台上,操作液压卷扬机实现管段在工作台面上位置的准确调整; 利用液压钳将管段夹住,操作气动胎芯自动行走,使其进入管段,并将胎芯撑起; 操作弯管液压缸,进行管线弯制;松开液压钳,操作液压卷扬机,使弯管在工作台面进行下一个弯管位置的准确调整; 重复 操作,实现下一次弯管动作。一般一根12m 长的管线需要进行152O次左右的弯管动作,才能达到最大l1的弯曲角度。2、步骤弯管机的基本原理与选择弯管机的弯曲原理,在普通情况下有以情二种,即滚弯式与缠绕式。如下图1、2分别是弯管原理图。二者各有优缺点。缠绕式主要用于方管的弯曲其结构复杂,而滚弯式主要用于圆管弯曲也可用于方管弯曲但没有缠绕式好,但结构简单。故本弯管机采用滚弯式。弯管的步骤大致是:1.留出第1段直线段长度,并夹紧管子。2.弯曲。3.松开夹紧块,取出管子,使模具复位。按管形标准样件在检验夹具上检查管形,并校正。4.重复第1步,直至弯完管子为止。 图1 弯管式弯曲 图2 缠绕式弯曲 工件工艺分析此工作件采用的直径为30mm厚为2mm是无缝钢管做为弯管件,材料为10号钢,其最小弯曲半径为60mm。而弯曲件的弯曲半径为100mm,固其符合加工工艺性。其工件如1-3图。弯管件要求不能有裂纹,不能有过大的外凸。不能有趋纹。1、电机选取。由经验选取弯管机的弯管速度为8r/min。2、传动比的计算与各传动装置的运动与参数。3、皮带轮与皮带的计算与选择由电机转速与功率,确定了采用普通A型皮带作为传动带。4、蜗轮蜗杆减速箱的计算与选择因为蜗轮蜗杆的安装为蜗杆在蜗轮的侧面所以选用CWS型的蜗轮蜗杆减速器5、联轴器的计算与选择由于此联轴器承受的力矩相对较大,且顾及性价比轴孔径的配合关系且弹性柱销齿式联轴器的结构简单,制造容易,不需用专用的加工设备,工作是不需润滑,维修方便,更换易损件容易迅速,费用低,因此选用弹性柱销齿式联轴器。6、轴承的选择由于弯管机需要一个平稳的平台且轴承同时受有径向力和轴向力的作用,故不能选用深沟滚子轴承。且轴承受力不大,转速也较低,故可选用圆锥滚子轴承,且可选取外径较小的以使空间更紧凑和降低成本。选用32912和32918二种圆锥轴承。7、轴的初步计算与设计及校核8、齿轮的计算与设计9、大小齿轴前后端盖及轴承座的结构设计10、轴套的结构设计11、机身的结构设计与计算12、弯管机的主要参数 挡料架的结构设计挡料架在弯管机上的作用主要是用来挡弯曲钢管时的反力,同时也具有定位的作用。 有如同夹具一般。由于本弯管机是采用滚弯式的弯管原理,故钢管与挡料轮的接触面较不大,故挡料轮的硬度不能比钢管的硬,故采用黄铜作为挡料轮的材料。挡料轮的结构主要由挡料轮、挡料轴、挡料轮架、轴承、键、轴盖、挡料座、螺纹杆、手轮等一些组成。 用电器选择与电路由于此弯管机采用的是半自动的形式,故采用二个行程开关和二个交流接触电器等组成其电路。由于电机的功率为3KW且电压为380Vh频率为50Hz的交流电。故选用行程开关的型号1LX19-131(B),接触器型选用1CJ-16,2常闭2常开,其工作功率为4KW。按钮使用普通型平钮二个,型号1为LA101P-P。电源开关选用LW8万能转换开关型号1为AC21,其工作功率为3.8KW。短路保护熔断器选用1RL6-25其额定功率为4KW。过载保护采用1JRS1-25/F系列热继电器JRS1-25/F其控制功率为380*3=1124W,因为有二根线所以总功率为1124*3=3372W故合适。电源线采用1BV4(B)即常用铜芯聚氯乙烯绝缘电线4平方毫米的铜线线芯结构为7*0.85。其额定电压为600V其电路设计如下, 任务完成的阶段安排及时间安排毕业设计(论文)进程安排:序号 设计(论文)各阶段名称 日期(教学周)1 外文资料翻译 第4周2 开题报告 第5、6周3 总体方案 第79周4 设计说明书 第15周 总结我们已经是世界上主要的弯管机生产国家之一,但是目前,管道施工应用的弯管机基本上都是进口的,国外比较著名的弯管机生产厂家有德国的VIETZ公司和美国的CRC公司。通用的技术都是利用静液压传动、气动控制技术来实现弯管机的弯管操作和控制。国内目前仍没有具备生产大型弯管机设计和制造能力的厂家。这主要是国内整体工业化程度不高,国产机械本身的加工精度不够以及专业人才的匮乏,加之国产钢材与进口钢材的差距是导致机械整体质量不高的主要原因。希望能通过这次设计对国内的机械方面有所了解,为努力发展中国的机械行业做出自己的一份贡献。 指导教师批阅意见 指导教师(签名): 年 月 日 2011届毕业设计 材 料 系 、 部: 机械工程系 学生姓名: 李衍 指导教师: 康煜华 职 称: 副教授 专 业:机械设计制造及其自动化班 级: 机本0704 学 号: 214070437 2011 年 6 月 外文翻译 结构设计结构设计Augustine J.Fredrich摘要:结构设计是选择材料和构件类型,大小和形状以安全有用的样式承担荷载。一般说来,结构设计暗指结构物如建筑物和桥或是可移动但有刚性外壳如船体和飞机框架的工厂稳定性。设计的移动时彼此相连的设备(连接件),一般被安排在机械设计领域。 关键词:结构设计 ; 结构分析 ; 结构方案 ; 工程要求Abstract: Structure design is the selection of materials and member type ,size, and configuration to carry loads in a safe and serviceable fashion .In general ,structural design implies the engineering of stationary objects such as buildings and bridges ,or objects that maybe mobile but have a rigid shape such as ship hulls and aircraft frames. Devices with parts planned to move with relation to each other(linkages) are generally assigned to the area of mechanical . Key words: Structure Design ; Structural analysis ;structural scheme ; Project requirements Structure Design Structural design involved at least five distinct phases of work: project requirements, materials, structural scheme, analysis, and design. For unusual structures or materials a six phase, testing, should be included. These phases do not proceed in a rigid progression , since different materials can be most effective in different schemes , testing can result in change to a design , and a final design is often reached by starting with a rough estimated design , then looping through several cycles of analysis and redesign . Often, several alternative designs will prove quite close in cost, strength, and serviceability. The structural engineer, owner, or end user would then make a selection based on other considerations.Project requirements. Before starting design, the structural engineer must determine the criteria for acceptable performance. The loads or forces to be resisted must be provided. For specialized structures, this may be given directly, as when supporting a known piece of machinery, or a crane of known capacity. For conventional buildings, buildings codes adopted on a municipal, county , or , state level provide minimum design requirements for live loads (occupants and furnishings , snow on roofs , and so on ). The engineer will calculate dead loads (structural and known, permanent installations ) during the design process. For the structural to be serviceable or useful , deflections must also be kept within limits ,since it is possible for safe structural to be uncomfortable “bounce” Very tight deflection limits are set on supports for machinery , since beam sag can cause drive shafts to bend , bearing to burn out , parts to misalign , and overhead cranes to stall . Limitations of sag less than span /1000 ( 1/1000 of the beam length ) are not uncommon . In conventional buildings, beams supporting ceilings often have sag limits of span /360 to avoid plaster cracking, or span /240 to avoid occupant concern (keep visual perception limited ). Beam stiffness also affects floor “bounciness,” which can be annoying if not controlled. In addition , lateral deflection , sway , or drift of tall buildings is often held within approximately height /500 (1/500 of the building height ) to minimize the likelihood of motion discomfort in occupants of upper floors on windy days .Member size limitations often have a major effect on the structural design. For example, a certain type of bridge may be unacceptable because of insufficient under clearance for river traffic, or excessive height endangering aircraft. In building design, ceiling heights and floor-to-floor heights affect the choice of floor framing. Wall thicknesses and column sizes and spacing may also affect the serviceability of various framing schemes.Materials selection. Technological advances have created many novel materials such as carbon fiber and boron fiber-reinforced composites, which have excellent strength, stiffness, and strength-to-weight properties. However, because of the high cost and difficult or unusual fabrication techniques required , they are used only in very limited and specialized applications . Glass-reinforced composites such as fiberglass are more common, but are limited to lightly loaded applications. The main materials used in structural design are more prosaic and include steel, aluminum, reinforced concrete, wood , and masonry . Structural schemes. In an actual structural, various forces are experienced by structural members , including tension , compression , flexure (bending ), shear ,and torsion (twist) . However, the structural scheme selected will influence which of these forces occurs most frequently, and this will influence the process of materials selection.Tension is the most efficient way to resist applied loads ,since the entire member cross section is acting to full capacity and bucking is not a concern . Any tension scheme must also included anchorages for the tension members . In a suspension bridge , for example ,the anchorages are usually massive dead weights at the ends of the main cables . To avoid undesirable changes in geometry under moving or varying loads , tension schemes also generally require stiffening beams or trusses. Compression is the next most efficient method for carrying loads . The full member cross section is used ,but must be designed to avoid bucking ,either by making the member stocky or by adding supplementary bracing . Domed and arched buildings ,arch bridges and columns in buildings frames are common schemes . Arches create lateral outward thrusts which must be resisted . This can be done by designing appropriate foundations or , where the arch occurs above the roadway or floor line , by using tension members along the roadway to tie the arch ends together ,keeping them from spreading . Compression members weaken drastically when loads are not applied along the member axis , so moving , variable , and unbalanced loads must be carefully considered. Schemes based on flexure are less efficient than tension and compression ,since the flexure or bending is resisted by one side of the member acting in tension while the other side acts in compression . Flexural schemes such as beams , girders , rigid frames , and moment (bending ) connected frames have advantages in requiring no external anchorages or thrust restrains other than normal foundations ,and inherent stiffness and resistance to moving ,variable , and unbalanced loads .Trusses are an interesting hybrid of the above schemes . They are designed to resist loads by spanning in the manner of a flexural member, but act to break up the load into a series of tension and compression forces which are resisted by individually designed tension and have excellent stiffness and resistance to moving and variable loads . Numerous member-to-member connections, supplementary compression braces ,and a somewhat cluttered appearance are truss disadvantages .Plates and shells include domes ,arched vaults ,saw tooth roofs , hyperbolic paraboloids , and saddle shapes .Such schemes attempt to direct all force along the plane of the surface ,and act largely in shear . While potentially very efficient ,such schemes have very strict limitations on geometry and are poor in resisting point ,moving , and unbalanced loads perpendicular to the surface.Stressed-skin and monologue construction uses the skin between stiffening ribs ,spars ,or columns to resist shear or axial forces . Such design is common in airframes for planes and rockets, and in ship hulls . it has also been used to advantage in buildings. Such a design is practical only when the skin is a logical part of the design and is never to be altered or removed .For bridges , short spans are commonly girders in flexure . As spans increase and girder depth becomes unwieldy , trusses are often used ,as well as cablestayed schemes .Longer spans may use arches where foundation conditions ,under clearance ,or headroom requirements are favorable .The longest spans are handled exclusively by suspension schemes ,since these minimize the crucial dead weight and can be erected wire by wire .For buildings, short spans are handled by slabs in flexure .As spans increase, beams and girders in flexure are used . Longer spans require trusses ,especially in industrial buildings with possible hung loads . Domes ,arches , and cable-suspended and air supported roofs can be used over convention halls and arenas to achieve clear areas .Structural analysis . Analysis of structures is required to ensure stability (static equilibrium ) ,find the member forces to be resisted ,and determine deflections . It requires that member configuration , approximate member sizes ,and elastic modulus ; linearity ; and curvature and plane sections . Various methods are used to complete the analysis .Final design . once a structural has been analyzed (by using geometry alone if the analysis is determinate , or geometry plus assumed member sizes and materials if indeterminate ), final design can proceed . Deflections and allowable stresses or ultimate strength must be checked against criteria provided either by the owner or by the governing building codes . Safety at working loads must be calculated . Several methods are available ,and the choice depends on the types of materials that will be used .Pure tension members are checked by dividing load by cross-section area .Local stresses at connections ,such as bolt holes or welds ,require special attention . Where axial tension is combined with bending moment ,the sum of stresses is compared to allowance levels . Allowable : stresses in compression members are dependent on the strength of material, elastic modulus ,member slenderness ,and length between bracing points . Stocky members are limited by materials strength ,while slender members are limited by elastic bucking . Design of beams can be checked by comparing a maximum bending stress to an allowable stress , which is generally controlled by the strength of the material, but may be limited if the compression side of the beam is not well braced against bucking .Design of beam-columns ,or compression members with bending moment ,must consider two items . First ,when a member is bowed due to an applied moment ,adding axial compression will cause the bow to increase .In effect ,the axial load has magnified the original moment .Second ,allowable stresses for columns and those for beams are often quite different .Members that are loaded perpendicular to their long axis, such as beams and beam-columns, also must carry shear. Shear stresses will occur in a direction to oppose the applied load and also at right angles to it to tie the various elements of the beam together. They are compared to an allowable shear stress. These procedures can also be used to design trusses, which are assemblies of tension and compression members. Lastly, deflections are checked against the project criteria using final member sizes. Once a satisfactory scheme has been analyzed and designed to be within project criteria, the information must be presented for fabrication and construction. This is commonly done through drawings, which indicate all basic dimensions, materials, member sizes, the anticipated loads used in design, and anticipated forces to be carried through connections.结构设计结构设计包含至少5个不同方面的工作:工程要求,材料,结构方案,分析和设计。对于不一般的结构或材料,又包含一个方面:试验。这些方面不是严格按步骤进行,因为不同材料在不同方案大多数是有效的,试验会导致设计变更,最终设计由初步估计设计开始,然后经过分析和再设计几个循环后完成。通常,可替代的设计证明在费用,强度和使用性上十分接近。结构工程师,业主或最后住户基于其它的考虑选择一种。工程要求。在开始设计前,结构工程师必须决定容易接受的执行标准。必须提供承担的荷载或力。对于一些专门结构,当支持一台已知载重的机器或起重机时,这可能直接给出,对于普通建筑物,采用市政,县,州的建筑规范,提供了设计所需活载(人群荷载和设备,屋顶雪荷载,等等)的最小值。工程师将计算出设计期间的恒载(结构和已知永久性设备)。对要正常使用的结构,也必须控制其挠度,因为安全的结构可能会存在令人不安的振动。机器的支座有严格的变形限制,因为梁下沉会导致驱动轴弯曲,烧毁,部件错位和上面的吊车熄火。挠度限制在跨度/1000 (梁长的1/1000)以下是很普通的。在传统建筑里,支持板的梁挠度限制在跨度1/360以避免粉刷开裂或跨度1/240以避免人的担忧(保持在可感知的变动范围内)。梁的刚度也影响板“振动”,如果不能控制会令人很头疼。另外,高层建筑的侧面变形,位移或摇摆通常限定在高度/500(建筑物高度的1/500)里,把在有风的日子里上面楼层的人移动的不舒服降到最小。构件尺寸在结构设计里起主要作用。例如,由于下面留作水上交通的净空不够或过高威胁到飞机的特定类型的桥是不可接受的。在建筑设计里,天花板高度和楼板之间高度影响楼板框架的选择。墙厚和柱子尺寸和跨度也影响不同框架方案的适用性。选择材料。技术的进步创造了许多新材料,如碳纤维加强复合材料和硼纤维加强复合材料,它们都具有极好的强度,刚度和强度重量比特性。然而,由于费用高和非通常的制造要求,它们仅用在有限特殊领域。强化玻璃合成物如玻璃纤维是很普遍,但被限制应用在小荷载情况下。用在结构设计上的主要材料更多是普通的,包括钢材,铝,钢筋混凝土,木材,砌体。结构方案。在一个实际方案里,结构构件承担很多力,包括拉,压,弯,剪和扭。然而所选择的方案将会影响这些力产生的概率,也会影响材料选择过程。 抗拉是有效的承担荷载的方法,整个构件的横截面性能得到发挥,并且不涉及到弯曲变形。任何抗拉方案必须也对抗拉构件的锚固。例如,在悬索桥里,锚固体通常是位于主要绳索尾段的强大自重。为了避免在荷载移动或变形时有不期望的几何变形,抗拉方案通常要求是刚性梁和桁架。抗压是另一个很有效的承担荷载方法。全部杆件截面发挥了作用,但是设计时必须避免弯曲,或者是做成粗短构件或者是增加附加支撑。圆顶和拱形建筑,拱桥和柱是很普遍的建筑方案。拱产生了必须抵挡住的水平外推力。这靠设计合适的基础或建在车道或楼板的上面的拱解决,靠沿着车道用抗拉构件把两端的拱连接起来,阻止他们拉开。当荷载不是作用在构件轴线上时,抗压构件显著地被削弱。所以,必须认真考虑移动,变化和不平衡的荷载。基于受弯的方案的效率比受拉和压低,因为弯曲是靠构件一边受拉另一边受压来抵抗。受弯方案如主梁,次梁,刚架和受弯框架在外部锚固或推力限制,与一般基础不同,靠内部刚度阻挡可移动,变化和不平衡的荷载的情况下有利。桁架是上面方案的混合体。它们设计成荷载横跨在受弯构件上,但是分解成一系列拉力和压力,由抗拉和抗压构件承担。桁架方案设计时不需要特殊锚固或推力的限制,并且有很好的刚度抵抗移动或变化的荷载。大量的构件之间连结和抗压构件的附加支撑,看起来有点杂乱,这就是桁架的不利处。板和壳包括圆顶,拱顶,有齿屋顶,双曲抛物面和马鞍形。这样的方案把所有的力直接作用在平板表面并且作用有巨大的剪力。尽管可能效率很高,但是这样的方案对几何有严格的限制,并且在移动,和不平衡垂直作用在表面的荷载的能力很弱。薄壳结构和硬壳结构利用加劲肋,梁之间的壳板抵抗剪力和轴向力。这样的设计在飞机机体和火箭,船体方面很普遍。它在建筑方面也是有利的。这样的设计仅仅在壳是设计的逻辑部分并且永远不会被替代和移除时才实际些。对于桥梁,短跨是很普遍受弯的梁。当跨度增加和梁高变得很大时,通常用桁架和斜拉结构。更长跨时也许用拱,要考虑基础条件和净空要求。最长的跨靠悬索方案处理,因为这可把关键性的自重降到最小并且能索连索地建造起来。对于桥,短跨靠板承担弯矩。当跨度增加时,主梁和次梁被用来承担弯曲。更长的跨要求用桁架,尤其是在工业建筑有吊车荷载时,圆顶,拱和悬索和充气屋顶被用在传统的大厅和竞技场里以获得净面积。结构分析。结构分析要求确定稳定性(静力平衡),构件承担的力和变形。它需要构件形状,大概尺寸,已知或假设的材料特性。分析包括:平衡,应力,应变和弹性模量,线形,塑性和弯曲和板截面。很多方法可以完成分析过程。最终设计。一旦结构分析完成(如果分析是正确的,只用几何方法;反之附加构件尺寸和材料假设)。最终设计可以进行,必须对照业主或政府建筑规范标准来检查变形和允许应力或极限强度。必须计算工作荷载下的安全性。一般方法是可行的,依据所使用的材料类型做出选择。纯抗拉构件检查横截面应力。特别注意螺栓孔或焊接处的应力。拉弯构件中,用应力之和与分析应力作比。受压构件中的允许应力取决于构件强度,弹性模量,长细比和支点间距离。粗短构件由材料强度决定,然而长细构件由弹性弯曲决定。梁的设计由对于最大弯曲应力和允许应力来检验,通常由材料强度控制,但是如果受压一边没有侧向支撑就会被限制。梁,柱或有弯矩的受压构件的设计必须考虑两项。首先,当构件由于承受弯矩而弯曲时,轴力会增加弯曲量,实际上,轴压放大了原始弯矩。其次,对于柱和梁的允许应力是不同的。承受垂直于长轴的荷载的构件。如梁和梁柱,也必须承担剪力。剪应力和荷载的方向相反并且在其右边,把梁的不同部分连接起来。它们与允许剪应力作对比。这些步骤也能用来设计由受拉和受压构件组成的桁架。最后,用工程标准检验变形,使用最后的构件。一旦被分析和在工程标准内的设计方案是令人满意的,必须提出制造和建立信息。通过作图,指明所以基本尺寸,材料和构件大小。设计中预期荷载和节点承担的预期力。
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