结构设计、可机加工性.docx

《结构设计、可机加工性.docx》由会员分享，可在线阅读，更多相关《结构设计、可机加工性.docx（20页珍藏版）》请在第一文库网上搜索。

1、外文翻译结构设计结构设计Augustine JFredrich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 servi

2、ceable fashion .Ingeneral ,structural design implies the engineering of stationary objects such asbuildings and bridges ,or objects that maybe mobile but have a rigid shape such asship hulls and aircraft frames. Devices with parts planned to move with relation toeach other(linkages) are generally as

3、signed to the area of mechanical Key words: Structure Design ； Structural analysis ； structural scheme ；Project requirementsStructure DesignStructural design involved at least five distinct phases of work: projectrequirements, materials, structural scheme, analysis, and design. For unusualstructures

4、 or materials a six phase, testing, should be included. These phases do notproceed in a rigid progression , since different materials can be most effective indifferent schemes , testing can result in change to a design , and a final design is oftenreached by starting with a rough estimated design ,

5、then looping through severalcycles of analysis and redesign . Often, several alternative designs will prove quiteclose in cost, strength, and serviceability. The structural engineer, owner, or end userwould then make a selection based on other considerations.Project requirements. Before starting des

6、ign, the structural engineer mustdetermine the criteria for acceptable performance. The loads or forces to be resistedmust be provided. For specialized structures, this may be given directly, as whensupporting a known piece of machinery, or a crane of known capacity. Forconventional buildings, build

7、ings codes adopted on a municipal, county , or , statelevel provide minimum design requirements for live loads (occupants and furnishings ,snow on roofs , and so on ) The engineer will calculate dead loads (structural andknown, permanent installations ) during the design process.For the structural t

8、o be serviceable or useful , deflections must also be keptwithin 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 cancause drive shafts to bend , bearing to burn out , parts to misalign , and o

9、verheadcranes 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 havesag limits of span /360 to avoid plaster cracking, or span /240 to avoid occupantconcern (keep visual perception limited ). Be

10、am stiffness also affects floor“bounciness J which can be annoying if not controlled. In addition , lateral deflection ,sway , or drift of tall buildings is often held within approximately height /500 (1/500of the building height) to minimize the likelihood of motion discomfort in occupantsof upper

11、floors on windy days .Member size limitations often have a major effect on the structural design. Forexample, a certain type of bridge may be unacceptable because of insufficient underclearance for river traffic, or excessive height endangering aircraft. In building design,ceiling heights and floor-

12、to-floor heights affect the choice of floor framing. Wallthicknesses and column sizes and spacing may also affect the serviceability of variousframing schemes.Materials selection. Technological advances have created many novel materialssuch as carbon fiber and boron fiber-reinforced composites, whic

13、h have excellentstrength, stiffness, and strength-to-weight properties- However, because of the highcost and difficult or unusual fabrication techniques required , they are used only invery limited and specialized applications . Glass-reinforced composites such asfiberglass are more common, but are

14、limited to lightly loaded applications. The mainmaterials 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 bystructural members , including tension , compression ,

15、 flexure (bending ), shear ,andtorsion (twist) However, the structural scheme selected will influence which of theseforces occurs most frequently, and this will influence the process of materialsselection.Tension is the most efficient way to resist applied loads ,since the entiremember cross section is acting to full capacity and bucking is not a concern . Anytension scheme must also included anchorages for the tension members In asuspension bridge , for example ,the anchorages are usually massive dead weig