衢州学院本科毕业设计(论文)外文翻译

1、衢州学院本科毕业设计(论文)外文翻译译文：建筑材料建筑材料必须具有对结构有用的某些物理性质。 首先，建筑材料必须能够承受荷载或重量，而不会永久改变其原有的形状。当荷载施加到结构单元上时，材料将发生变形，也就是说，线材将伸长或梁将会弯曲。然后卸载后，线材和梁将恢复原状。材料的这种性质称为弹性。如果某种材料是非弹性的，在卸荷后结构将残留变形，重复加荷和卸荷，结构的变形将持续增加，直至最后结构失效。用于建筑结构的所有材料，诸如砖石、木材、钢材、铝材、钢筋混凝土的塑料等，在一定范围的荷载作用下均表现出弹性如果荷载增加超过这个范围，材料将表现出两种类型的性质：脆性和塑性。若为前者，材料将会突然断裂；若为

2、后者，材料在达到某一荷载（屈服强度）开始塑性流动，最后破坏。例如，钢材表现出塑性，石材则是脆性的。材料的最终强度用材料破坏时的极限应力来表示。建筑材料第二个重要性质是刚度。这一性质用弹性模量来表示，弹性模量是应力（单位面积上的力）和应变（单位长度上的变形）的比值。因而弹性模量是衡量材料在荷载作用下抵抗变形能力的指标。对于相同荷载作用下相同面积的两种材料，弹性模量越高者变形越小。结构钢材，其弹性模量是3*108LB/IN2，或21000000kg/cm2，是铝材刚度的3倍、混凝土刚度的10倍、木材刚度的15倍。砌体，砌体包含天然材料，如石材、人造产品如混凝土砌块。砌体出现在远古时期。在古巴比轮城

3、市，泥土砖用于建造非宗教性建筑物，而石材被广泛用语尼罗河流域雄伟的寺庙。高及481ft(147m)的埃及大金字塔是最为壮观的石工材料。最初，砌块的叠砌是不用胶粘剂的，但所有现代土砖或页岩砖以及混凝土砌块。砌体材料基本上属于受压材料，不能承受张拉力，亦即拉力。砌体的极限抗压强度取决于砌体和砂浆。极限强度在1000到4000lb/in2(70280 kg/cm2)之间变化，其值取决于所有块体和砂浆的具体结合。木材，木材是一种最古老的建筑材料，是少数具有抗拉性能的天然材料之一。全世界已经发现的木材种类有数百种，每一类都表现出不同的物理特性。只有少数木材在建筑中被用做结构构件。例如，在美国，600多中

4、木材中仅有20种被用于结构。这些木材通常是一些针叶树或软木材，主要因为这两种木材资源丰富以及易于成型。在美国建筑中较为普遍使用的木材树种是花期松、南木松、云杉和红木。这些木材的极限抗拉强度变化范围为50008000 lb/in2（350560 kg/cm2）。硬木材主要用于细木工或用于铺地板之类的室内装修。由于木材本身有细胞状结构，其顺纹强度要大于其横纹强度，木材顺纹的抗拉强度和抗压强度尤其高，并且有很好的抗弯强度。这些性质使得木材成为建筑结构中柱和梁的理想材料。但是，由于桁架杆件中抗拉强度取决与各种杆件的连接，所以木材不能有效地在桁架中用作受拉构件。尽管为了利用木材的抗拉强度制造出许多金属节

5、点，但很难设计出与顺纹剪切强度或抗裂强度关系不大的接头。钢材，钢材是一种优异的结构材料。与其他材料相比，钢材有高强度质量比（单位质量的强度），即在相同体积条件下其质量是木材的10倍以上。钢材具有较高的弹性模量，这就使得钢筋在荷载作用下变形较小。钢材可被轧制成各种不同的结构形状，如工字型梁、钢板和压型钢板，还能被铸造成复杂形状，也能用以生产出钢丝和钢绞线，用作悬索桥和旋索屋面的钢缆，电梯升运机缆索，或用作预应力混凝土的钢丝绞线。钢制构件可以用多种方法进行连接，如螺栓连接、铆接或焊接。碳素钢易遭氧化导致腐蚀，必须防止其与大气的接触，可采用在其上刷防锈或将其埋入混凝土的办法。当温度高于700F（37

6、1）时，钢材将迅速丧失其强度，因而必须在其外包裹上防火材料（通常为混凝土）对其加以保护。合金元素如硅或锰的加入使钢材强度变得更高，其抗拉强度可达250000 LB/IN2（17500kg/cm2）。当结构构件的尺寸变得重要时，如摩天大楼的柱子，就要使用这类合金钢。铝材，当轻质、强度和防腐蚀能力成为建筑考虑的重要因素时，铝材作为一种建筑材料就显得特别有用。因为纯铝极软，易延展，必须在其中加入锰、硅、锌和铜这些合金元素，使其获得结构所要求的强度。建筑用铝合金表现出弹性，其弹性模量是钢材的1/3，因而在相同荷载作用下，其变形为钢材的3倍。铝合金的密度为钢材的1/3，因而在相似强度条件下，铝合金构件比

7、钢材构件轻。铝合金的极限抗拉强度范围在20006000lb/in2(14004200kg/cm2)。铝材能被加工成各种状态，可以被挤压成工字型梁，拔成线材和杆件，辊压成铝箔和板材。铝构件可以像钢材一样采用铆接、螺钉连接以及（较少地）焊接等方式进行连接。铝除了用作建筑和预制房屋的框架构件以外，还被广泛地用作窗框，以及幕墙建筑物的幕墙材料。混凝土，混凝土是水、砂石子和波特兰水泥和混合物。碎石、人造轻骨料、贝壳经常被用以代替天然石料。波特兰水泥，是将由钙质材料和黏土质材料形成的混合物在窑中进行煅烧然后进行粉磨而形成的。混凝土强度即源于磨细的水泥与水混合时经水化而硬化的过程。在理想的混合状态下，混凝土

8、由占其体积大约3/4的砂、石子和占其体积1/4的水泥浆组成。混凝土的物理特性对其组成成分变化是极其敏感的，所以为了获得混凝土在强度和收缩等方面特定的效果，必须对这些组成材料的配料进行特定的设计。当往模具或模板中浇注时，混凝土中含有大量并非用于水化而是要蒸发掉的水。混凝土硬化时，经过一段时间将蒸发掉多余的水而产生收缩，这种收缩通常将导致细裂缝的发展。为了将这些裂缝减至最少，混凝土硬化时必须保持潮湿状态至少在5天以上。以为混凝土的水化过程能持续进行多年，故其强度能够持续增长。事实上，常把混凝土28天的强度视为标准强度。混凝土在荷载作用下会发生弹性变形。尽管混凝土的弹性模量是钢材的1/10，但由于其

9、强度也大约是钢材的1/10，所以它们有相似的变形。混凝土主要用作抗拉材料，其抗拉强度可不予考虑。钢筋混凝土，钢筋混凝土中配有钢筋，用以承受混凝土构件中的拉力。这些钢筋的直径范围在0.25in（0.64cm）2.25in(5.7cm)，其表面带肋，以保证与混凝土的黏结。尽管钢筋混凝土在很多国家得到发展，但其发展一般归功于约瑟夫，一位法国园丁，他在1868年曾使用钢筋网片来加强混凝土管，因为温度变化时，钢材与混凝土胀缩系数相同，所以这种做法是可行的，如若不然，钢材与混凝土的黏结会因温度的变化导致两者变形不一致而破坏。钢筋混凝土可以浇注成各种形状，如梁、柱、板和拱，因而适用于特殊形态的建筑物。钢筋混

10、凝土的极限强度抗拉强度可能会超过10000lb/in2(700kg/cm2)，尽管产生的大部分商品混凝土的强度低于6000lb/in2(420kg/cm2)。塑料，塑料因其多样性、强度、耐久性和轻质而迅速成为一种重要的建筑材料。塑料是一种合成材料或树脂，能按要求塑造成各种形状，采用有机物作胶粘剂。有机的塑料分为两大类：热固性塑料和热塑性塑料。热固性塑料受热时发生化学变化而变硬，一旦成型，着类塑料不能在塑成型。热塑性塑料在高温时仍保持柔软，冷却后才变硬，这类塑料通常不能用作建筑材料。原文：Build materialsMaterials for building must have certai

11、n physical properties to be structurally useful. primarily ,they must be able to carry a load , or weight , without changing shape permanently . when a load is applied to a structure member , it will deform ; that is , a wire will stretch or a beam will bend . however , when the load is removed ,the

12、 wire and the beam come back to the original position ,this material property is called elasticity ,if a material were not elastic and a deformation were present in structure after removal of the load , repeated loading and unloading eventually would increase the deformation to the point where the s

13、tructure would become useless . all material used in architectural structure , such as stone and brick , wood , steel , aluminum , reinforced concrete ,and plastics , behave elastically within a certain defined range of loading . if the loading is increased above the range , two type of behavior can

14、 occur ; brittle and plastic . in the former , the , material will break suddenly . in the latter , the material begins to flow at a certain load (yield strength) , ultimately leading to fracture . as example , steel exhibits plastic behavior , and stone is brittle . the ultimate strength of a mater

15、ial is measured by the stress at which failure (fracture) occurs .A second important property of a building is its stiffness . this property is defined by the elastic modulus ,which is the ratio of the stress (force per unit area) , to the strain (deformation per unit length) . the elastic modulus ,

16、 therefore , is a measure of the resistance of a material to deformation under load . for two material to equal area under the same load , the one with the higher elastic modulus has the smaller deformation .structural steel , which has an elastic modulus of 30 million pounds per square inch (psi) ,

17、 or 2100000 kilograms per square centimeter , is 3 time as stiff as aluminum , 10 times as stiff as concrete , and 15 times as stiff as wood .Masonry consists of natural materials , such as stone , or manufactured products , such as brick and concrete block . masonry has been used since ancient time

18、s ; mud brick were used in the city of Babylon for secular buildings , and stone was used for the great temples of the Nile Valley . the great pyramid in Egypt . standing 481 feet (147 meters) high , is the most spectacular masonry construction . masonry units originally were stacked without using a

19、ny bonding agent , but all modern construction uses a cement mortar as a bonding material . modern structural materials include stone , brick of burnt clay or slate , and concrete blocks .Masonry is essentially a compressive material ; it cannot withstand a tensile force , that is , a pull. The ulti

20、mate compressive strength of bonded masonry depends on the strength of the masonry until and the mortar. The ultimate strength will vary form 1000 to 4000 psi (70 to 280 kg/sq cm), depending on the particular combination of masonry unit and mortar used.Timber is one of the earliest construction mate

21、rials and one of the few natural materials with good tensile properties. Hundreds of different species of wood are found throughout the world , and each species exhibits different physical characteristics. Only a few species are used structurally as framing members in building construction. In the u

22、ntied states, for instance, out of more than 600 species of wood, only 20 species are used structurally. These are generally the conifers, or softwoods, both because of their abundance and because of the ease with which their wood can be shaped. The species of their more commonly used in the untied

23、states for construction are Douglas fir, southern pine, spruce, and redwood. The ultimate tensile strength of these species varies form 5000 to 8000 psi (350 to 560 kg/sq cm). Hardwood are used primarily for cabinetwork and for interior finishes such as floors.Because of the cellular of wood, it is

24、stronger along the grain than across the grain. Wood id particularly strong in tension and compression parallel to the grain. And it has great bending strength. These properties make it ideally suited for columns and beams in structures. Wood is not effectively used as a tensile member in a truss, h

25、owever, because the tensile strength of a truss member depends upon connections between members. It is difficult to devise connections which do not depend on the shear or tearing strength along the grain, although numerous metal connectors have been produced to utilize the tensile strength of timber

26、s.Steel is an outstanding structural material. It has a high strength on a pound-for-pound basis when compared to other materials, even thought its volume-for-volume weight is more than times that of wood. It has a high elastic modulus, which results in small deformations under load. It can be forme

27、d by rolling into various structural shapes such as I-beams, plates, and sheets; it also can be cast into complex shapes; and it is also produced in the form of wire strands and ropes for use as cables in suspension bridges and suspended roofs, as elevator rope, and as wire for pestering concrete. S

28、teel element can be joined together by various means, such as bolting, riveting, or welding. Carbon steels are subject to corrosion through oxidation and must be protected form contact with the atmosphere by painting them or embedding them in concrete. Above temperatures of about 700F(371), steel ra

29、pidly loses its strength, and therefore it must be covered in a jacket of a fireproof material(usually concrete) to increase its fire resistance.The addition of alloying elements, such as silicon or manganese, results in higher strength steels with tensile strengths up to 250000 psi(17500kg/sq cm).

30、These steels are used where the size of a structural member become critical, as in the case of columns in a skyscraper. Aluminum is especially useful as a building when lightweight, strength, and corrosion are all important factors. Because pure aluminum is extremely soft and ductile, alloying eleme

31、nts, such as magnesium, silicon, zinc, and copper, must be added to it to impart the strength required for structural use. Structural aluminum alloys behave elastically. They have an elastic modulus one third as great as steel and therefore deform there times as much as steel under the same load. Th

32、e unit weight of an aluminum alloy is one third that of steel, and therefore an aluminum member will be lighter than a steel member of comparable strength. The ultimate tensile strength of aluminum alloys ranges form 20000 to 60000 psi (1400 to 4200kg/sq cm).Aluminum can be formed into a variety of

33、shapes; it can be extruded to form I-beams, drawn to form wire and rode, and rolled to form foil and plates. Aluminum members can be put together in the same way as steel by riveting, bolting, and (to a lesser extent) by welding. Apart form its use for framing members in buildings and prefabricated

34、housing, aluminum also finds extensive use for window frames and for skin of the building in curtain-wall construction.Concrete is a mixture of water, sand and gravel, and Portland cement. Crushed stone, manufactured lightweight stone, and seashells are often use in lieu of natural gravel. Portland

35、cement, which is a mixture of materials containing calcium and clay, is heated in a kiln and then pulverized. Concrete derives its strength form the fact that pulverized Portland cement, when mixed with water, hardens by a process called hydration. In an ideal mixture, concrete consists of about thr

36、ee fourths sand gravel (aggregate) by volume and one cement paste. The physical properties of concrete are highly sensitive to variations in the mixture of the components, so a particular combination of these ingredients must be custom-designed to achieve specified results in terms of strength or sh

37、rinkage. When concrete is poured into a mold or form, it contains free water, not required for hydration, which evaporate. As the concrete hardens, it releases this excess water over a period of time and shrinks. As a result of this shrinkage, fine cracks often develop. In order to minimize these sh

38、rinkage cracks, concrete must be hardened by keeping it moist for at least 5 days. The strength of concrete in time because the hydration process continues for years; as a practical matter, the strength at 28 days is considered standard.Concrete deform under load in an elastic manner. Although its e

39、lastic modulus is one tenth that of steel, similar deformations will result since its also about one tenth that of steel. Concrete is basically a compressive material and has negligible tensile strength.Reinforced concrete, Reinforced concrete has steel bars that are placed in a concrete member to c

40、arry tensile force. These Reinforced bars, which range in diameter form 0.25 inch(0.64cm) to 2.25 inches (5.7cm), have wrinkles on the surfaces to ensure a bond with the concrete. Although reinforced concrete was developed in many countries, its discovery usually is attributed to Joseph Monnier, a French gardener, who used a w