1、會計學1機械工程專業英語機械工程專業英語機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Bolted joints are one of the most common elements in construction and machine design. They consist of cap screws or studs that capture and join other parts, and are secured with the mating o

2、f screw threads.There are two main types of bolted joint designs. In one method the bolt is tightened to a calculated clamp load, usually by applying a measured torque load. The joint will be designed such that the clamp load is never overcome by the forces acting on the joint (and therefore the joi

3、ned parts see no relative motion). The other type of bolted joint does not have a designed clamp load but relies on the shear strength of the bolt shaft. This may include clevis linkages, joints that can move, and joints that rely on locking mechanism (like lock washers, thread adhesives, and lock n

4、uts).第1頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Bolted joint Screw joint Stud joint 第2頁/共46頁Bolt The bolt assembly is used when joint parts are not too thick to drill through holes.螺栓螺栓 用于聯接二通孔薄件用于聯接二通孔薄件第3頁/共46頁 Stud Stud are used in situations

5、 where a part with a through hole and a part with blind tapped hole.雙頭螺柱雙頭螺柱 用于聯接一通孔薄件和一盲孔厚件。用于聯接一通孔薄件和一盲孔厚件。第4頁/共46頁Screw Screws are mostly used for the cases with small bearing forces. such as inspection covers which have to be removed frequently.螺釘螺釘 多用于用于受力不大需要經常拆卸的情況多用于用于受力不大需要經常拆卸的情況第5頁/共46頁Nu

6、t are used to match the other screw fasteners. 螺母螺母 與其他螺紋件配合使用與其他螺紋件配合使用第6頁/共46頁Washer are used to match the other screw fasteners. 墊圈墊圈 與其他螺紋件配合使用與其他螺紋件配合使用第7頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Theory The clamp load, also called preload, o

7、f a cap screw is created when a torque is applied, and is generally a percentage of the cap screws proof strength. Cap screws are manufactured to various standards that define, among other things, their strength and clamp load. Torque charts are available that identify the required torque for cap sc

8、rews based on their property class or grade. When a cap screw is tightened it is stretched, and the parts that are captured are compressed. The result is a spring-like assembly. External forces are designed to act on the parts that have been compressed, and not on the cap screw.第8頁/共46頁機械工程專業英語機械工程專

9、業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Theory The result is a non-intuitive distribution of strain; in this engineering model, as long as the forces acting on the compressed parts do not exceed the clamp load, the cap screw do not see any increased load. This mo

10、del is only valid when the members under compression are much stiffer than the cap screw. This is a simplified model. In reality the bolt will see a small fraction of the external load prior to it exceeding the clamp load, depending on the compressed parts stiffness with respect to the hardwares sti

11、ffness. 第9頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Theory The results of this type of joint design are: Greater preloads in bolted joints reduce the fatigue loading of the hardware. For cyclic loads, the bolt does not see the full amplitude of t

12、he load. As a result, fatigue life can be increased or, if the material exhibits an endurance limit, extended indefinitely. As long as the external loads on a joint dont exceed the clamp load, the hardware doesnt see any motion and will not come loose (no locking mechanisms are required). In the cas

13、e of the compressed member being less stiff than the hardware (soft, compressed gaskets for example) this analogy doesnt hold true. The load seen by the hardware is the preload plus the external load.第10頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints 第

14、11頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Theory The results of this type of joint design are: Greater preloads in bolted joints reduce the fatigue loading of the hardware. For cyclic loads, the bolt does not see the full amplitude of the load.

15、 As a result, fatigue life can be increased or, if the material exhibits an endurance limit, extended indefinitely. As long as the external loads on a joint dont exceed the clamp load, the hardware doesnt see any motion and will not come loose (no locking mechanisms are required). In the case of the

16、 compressed member being less stiff than the hardware (soft, compressed gaskets for example) this analogy doesnt hold true. The load seen by the hardware is the preload plus the external load.第12頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Thread st

17、rength Nut threads are designed to support the rated clamp load of their respective bolts. If tapped threads are used instead of a nut, then their strength needs to be calculated. Steel hardware into tapped steel threads requires a depth of 1.5 thread diameter to support the full clamp load. If an a

18、ppropriate depth of threads is not available, or the threads are in a weaker material than the cap screw, then the clamp load (and torque) needs to be derated appropriately.第13頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Failure modes The most commo

19、n mode of failure is overloading. Operating forces of the application produce loads that exceed the clamp load and the joint works itself loose, or fails catastrophically.Over torquing will cause failure by damaging the threads and deforming the hardware, the failure might not occur until long after

20、ward. Under torquing can cause failures by allowing a joint to come loose. It may also allow the joint to flex and thus fail under fatigue. Brinelling may occur with poor quality washers, leading to a loss of clamp load and failure of the joint. Corrosion, embedment and exceeding the shear stress li

21、mit are other modes of failure.第14頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、一、Background informationLesson 19 Screws, fasteners and joints Notes:Brinelling refers to a material surface failure caused by contact stress that exceeds the material limit. This failure is caused by just one application of a load g

22、reat enough to exceed the material limit. The result is a permanent dent or brinell mark. Embedment is a phenomenon in mechanical engineering in which the surfaces between mechanical members of a loaded joint embed. It can lead to failure by fatigue as described below, and is of particular concern w

23、hen considering the design of critical fastener joints.第15頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、預備知識一、預備知識Lesson 19 Screws, fasteners and joints 1、基本類型、基本類型u普通螺栓聯接：被聯接件上通孔和螺栓桿間留有間隙，故普通螺栓聯接：被聯接件上通孔和螺栓桿間留有間隙，故精度低、結構簡單。精度低、結構簡單。u鉸制孔用螺栓聯接：孔和螺栓桿多采用基孔制過渡配合（鉸制孔用螺栓聯接：孔和螺栓桿多采用基孔制過渡配合（H7/m6、H7/n6）,精確固定被聯接件的相對位置，并可

24、承受精確固定被聯接件的相對位置，并可承受橫向載荷。橫向載荷。u雙頭螺栓聯接：被聯接件之一太厚或經常拆裝雙頭螺栓聯接：被聯接件之一太厚或經常拆裝u螺釘聯接：不用螺母，比雙頭螺柱簡單，用途相似，多用螺釘聯接：不用螺母，比雙頭螺柱簡單，用途相似，多用于受力不大、不需經常拆裝的場合于受力不大、不需經常拆裝的場合u緊定螺釘聯接：固定兩零件的相對位置，可傳遞不太大的緊定螺釘聯接：固定兩零件的相對位置，可傳遞不太大的扭矩和力扭矩和力u螺栓的類型：六角頭螺栓和雙頭螺栓螺栓的類型：六角頭螺栓和雙頭螺栓u螺釘的類型：半圓頭、平頭、六角頭、圓柱頭、沉頭螺釘的類型：半圓頭、平頭、六角頭、圓柱頭、沉頭 第16頁/共46

25、頁機械工程專業英語機械工程專業英語預備知識預備知識 一、預備知識一、預備知識Lesson 19 Screws, fasteners and joints 2、螺紋的預緊、螺紋的預緊u預緊的目的：增強聯接的可靠性、緊密性，防止預緊的目的：增強聯接的可靠性、緊密性，防止受載后被聯接件間出現縫隙或發生相對滑移。選用受載后被聯接件間出現縫隙或發生相對滑移。選用較大的預緊力可提高聯接的可靠性和疲勞強度較大的預緊力可提高聯接的可靠性和疲勞強度u預緊應力不超過其材料的屈服極限的預緊應力不超過其材料的屈服極限的80%。u控制預緊力的方法：控制預緊力的方法： 1）借助測力矩扳手或定力矩扳手）借助測力矩扳手或定力

26、矩扳手 2）測定螺栓伸長量）測定螺栓伸長量第17頁/共46頁機械工程專業英語機械工程專業英語預備知識預備知識 一、預備知識一、預備知識Lesson 19 Screws, fasteners and joints 3、螺紋的防松、螺紋的防松u螺紋升角小于螺旋副的當量摩擦角螺紋升角小于螺旋副的當量摩擦角 ：自鎖性好：自鎖性好u螺母與螺栓頭部等支承面上的摩擦力螺母與螺栓頭部等支承面上的摩擦力u摩擦防松：鎖緊螺母、彈簧墊圈、自鎖螺母摩擦防松：鎖緊螺母、彈簧墊圈、自鎖螺母u機械防松：開口銷與槽形螺母、止動墊圈機械防松：開口銷與槽形螺母、止動墊圈u鉚沖防松：端鉚、沖點鉚沖防松：端鉚、沖點第18頁/共46頁

27、詞詞 匯匯 二、詞匯二、詞匯screw 螺釘、螺紋螺釘、螺紋 bolt 螺栓螺栓 nut 螺母螺母 stud bolt 雙頭螺栓雙頭螺栓 washer 墊圈墊圈 thread 螺紋螺紋機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第19頁/共46頁課文分析課文分析機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints Typical methods of fastening and joining parts include the use of such items as b

28、olts, nuts, cap screws, setscrews, rivets, locking devices and keys. Parts may also be joined by welding, brazing, or clipping together. Studies in engineering graphics and in metal processes often include instruction on various joining methods, and the curiosity of any person interested in engineer

29、ing naturally results in acquisition of a good background of fastening methods. 第20頁/共46頁Typical methods of fastening and joining parts include the use of such items as bolts, nuts, cap screws, setscrews, rivets, locking devices and keys.課文分析課文分析典型的緊固件和聯接件包括諸如螺栓、螺帽、有頭典型的緊固件和聯接件包括諸如螺栓、螺帽、有頭螺釘、緊定螺釘、鉚釘

30、、鎖緊裝置和鍵。螺釘、緊定螺釘、鉚釘、鎖緊裝置和鍵。 Parts may also be joined by welding, brazing, or clipping together. 零件聯接也可以用熔焊、銅焊和夾緊的方法。零件聯接也可以用熔焊、銅焊和夾緊的方法。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第21頁/共46頁Studies in engineering graphics and in metal processes often include instruction on various joining

31、methods, and the curiosity of any person interested in engineering naturally results in acquisition of a good background of fastening methods. 課文分析課文分析在工程圖和金屬加工工藝研究中常常包括關于各種在工程圖和金屬加工工藝研究中常常包括關于各種聯接方法的說明，在工程上對此很感興趣的，求知聯接方法的說明，在工程上對此很感興趣的，求知欲強的任何人自然會獲得關于固緊方法上良好的基欲強的任何人自然會獲得關于固緊方法上良好的基礎知識。礎知識。 機械工程專業英語

32、機械工程專業英語Lesson 19 Screws, fasteners and joints 第22頁/共46頁課文分析課文分析機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints If an uninformed person were asked to choose the dullest and most uninteresting subject in mechanical design that he could imagine, he might well choose the subject of fasteners, th

33、at is, nuts and bolts. In fact, the term “nuts and bolts” is synonymous with hard and monotonous work, necessary but totally uninteresting tasks. Could one seriously imagine a group of nut and bolt manufacturers organizing an association and getting together for annual meeting? What subject could po

34、ssibly be of any interest? 第23頁/共46頁If an uninformed person were asked to choose the dullest and most uninteresting subject in mechanical design that he could imagine, he might well choose the subject of fasteners, that is, nuts and bolts. 課文分析課文分析如果讓一個對緊固件不甚了解的人去選擇他能想象如果讓一個對緊固件不甚了解的人去選擇他能想象的機械設計方面最

35、枯燥無味的學科的話，那么他就的機械設計方面最枯燥無味的學科的話，那么他就會選擇緊固件學科，即螺栓和螺帽。會選擇緊固件學科，即螺栓和螺帽。 In fact, the term “nuts and bolts” is synonymous with hard and monotonous work, necessary but totally uninteresting tasks. 事實上，術語事實上，術語“螺栓和螺帽螺栓和螺帽”是與艱苦、單是與艱苦、單調的工作同義，乏味但必須的工作。調的工作同義，乏味但必須的工作。 機械工程專業英語機械工程專業英語Lesson 19 Screws, faste

36、ners and joints 第24頁/共46頁Could one seriously imagine a group of nut and bolt manufacturers organizing an association and getting together for annual meeting? What subject could possibly be of any interest? 課文分析課文分析可以認真地設想有一群螺栓螺帽制造者組成一個協可以認真地設想有一群螺栓螺帽制造者組成一個協會并在一起召開年會嗎？那么還有什么學科不能讓會并在一起召開年會嗎？那么還有什么學科不

37、能讓人感興趣呢？人感興趣呢？ In spite of this taint, the subject is one of the most interesting in the entire field of mechanical design. 盡管存在這一偏見，但是這一學科在機械設計整盡管存在這一偏見，但是這一學科在機械設計整個領域中卻是最使人感興趣的學科之一。個領域中卻是最使人感興趣的學科之一。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第25頁/共46頁The number of new inventions in t

38、he fastener field over any period you might care to mention has been tremendous. 課文分析課文分析在緊固件領域新發明的數目巨大超過你能注意到的在緊固件領域新發明的數目巨大超過你能注意到的任何時期任何時期There is an overwhelming variety of fasteners available for the designers selection. 數不勝數的緊固件可供設計者任意選擇使用。數不勝數的緊固件可供設計者任意選擇使用。 機械工程專業英語機械工程專業英語Lesson 19 Screws,

39、 fasteners and joints 第26頁/共46頁Another thing: did you know that a good bolt material should be strong and tough, but a good nut material should be soft and ductile? 課文分析課文分析還有，你知道嗎？好的螺栓的材料應該是堅固而有還有，你知道嗎？好的螺栓的材料應該是堅固而有韌性，而好的螺帽的材料應該是軟而有塑性的。韌性，而好的螺帽的材料應該是軟而有塑性的。 Or did you know that there are certain a

40、pplications where you should tighten the bolt as tightly as possible and, if it does not fail by twisting the bolt in two during tightening, there is a very good possibility that the bolt never will fail? 或者你知道嗎或者你知道嗎?在某些應用中你應該盡可能地把它們在某些應用中你應該盡可能地把它們旋緊，如果在上緊過程中，由于旋緊這螺栓過程中旋緊，如果在上緊過程中，由于旋緊這螺栓過程中而未發生失效

41、現象，那么螺栓將可能永遠不會失效。而未發生失效現象，那么螺栓將可能永遠不會失效。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第27頁/共46頁In the material to follow you will discover the why of these questions. You will learn why a nut or bolt loosens and what you must do to keep it tight. 課文分析課文分析在下面的文字中你將發現這些問題的原因。你將掌在下面的文字中你將發現這些

42、問題的原因。你將掌握螺栓、螺帽為什么會松動和你必須怎樣令它保持握螺栓、螺帽為什么會松動和你必須怎樣令它保持旋緊狀態。旋緊狀態。 Methods of joining parts are extremely important in the engineering of a quality design, and it is necessary to have a thorough understanding of the performance of fasteners and joints under all conditions of use and design. 聯接件的聯接方法在保證

43、工程設計質量方面是極端聯接件的聯接方法在保證工程設計質量方面是極端重要的。在設計和使用的各種情況下，充分了解緊重要的。在設計和使用的各種情況下，充分了解緊固件和聯接件的性能那是必要的。固件和聯接件的性能那是必要的。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第28頁/共46頁Jumbo jets such as Boeings 747 and Lockheeds 1011 require as many as 2.5 million fasteners, some of which cost several dollars a

44、piece. 課文分析課文分析大型噴氣發動機客機像被音大型噴氣發動機客機像被音747和洛克希德和洛克希德1011，需要需要250萬個緊固件，有些每個要花數美元。萬個緊固件，有些每個要花數美元。 The 747, for example, needs about 70,000 titanium fasteners, costing about $150,000 in all; 400,000 other close-tolerance fasteners, costing about $250,000; and 30,000 squeeze rivets priced at 50 cents e

45、ach, installed. 例如波音例如波音747，大約需要裝，大約需要裝70000個鈦合金緊固件，個鈦合金緊固件，全部大約要花全部大約要花150000美元；美元；400000個具有精密公差個具有精密公差的其他緊固件，大約要花的其他緊固件，大約要花250000美元；和美元；和30000個個擠壓用鉚釘，安裝后每個價值擠壓用鉚釘，安裝后每個價值50美分。美分。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第29頁/共46頁To keep cost down, Boeing, Lockheed, and their subcont

46、ractors constantly review new fastener designs, installation techniques, and tooling. 課文分析課文分析為了降低成本，波音、洛克希德和他們的承包商為了降低成本，波音、洛克希德和他們的承包商不斷重新審查緊固件的設計、安裝和切削加工。不斷重新審查緊固件的設計、安裝和切削加工。 Cost-saving designs and tooling will find a ready market, which will grow in value as jumbo jets proliferate. 節省的設計和加工成本將

47、開發一個暢銷市場，增長節省的設計和加工成本將開發一個暢銷市場，增長的價值那將像坐上噴氣式飛機一樣。的價值那將像坐上噴氣式飛機一樣。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints pru5lifreitvi. 激增激增; 繁殖繁殖; 增增生生第30頁/共46頁Fasteners are named according to how they are intended to be used rather than how they are actually employed in specific instances. 課文分析課文分

48、析緊固件是根據將如何使用他們來命名的，而不是緊固件是根據將如何使用他們來命名的，而不是根據其在具體例子中的實際應用命名的。根據其在具體例子中的實際應用命名的。 If this basic fact is remembered, it will not be difficult to distinguish between a screw and a bolt. 如果記住了這個基本事實，就將不難區別螺釘和螺如果記住了這個基本事實，就將不難區別螺釘和螺栓。栓。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第31頁/共46頁If a

49、product is designed so that its primary purpose is assembly into a tapped hole, it is a screw. Thus a screw is tightened by exerting torque on the head. If a product is designed so that it is intended to be used with a nut, it is a bolt. 課文分析課文分析如果所設計的產品其主要目的是把它裝入到已攻如果所設計的產品其主要目的是把它裝入到已攻絲的螺紋孔中，那就是螺釘

50、。這樣螺釘是要在螺絲的螺紋孔中，那就是螺釘。這樣螺釘是要在螺釘頭上施加扭矩來旋緊的。如果所設計的產品打釘頭上施加扭矩來旋緊的。如果所設計的產品打算跟螺母配合使用，那就是螺栓。算跟螺母配合使用，那就是螺栓。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第32頁/共46頁A bolt is tightened by exerting torque on the nut. A stud resembles a threaded rod; one end assembles into a tapped hole, the other e

51、nd receives a nut. 課文分析課文分析螺栓是靠在螺母上施加扭矩來旋緊的。雙頭螺栓螺栓是靠在螺母上施加扭矩來旋緊的。雙頭螺栓就像刻了螺紋的桿，一端旋入螺紋孔中，另一端就像刻了螺紋的桿，一端旋入螺紋孔中，另一端再裝上螺帽。再裝上螺帽。It is the intent, rather than the actual use, which determines the name of a product. 因而根據使用的目的來確定產品名稱，并不是根據因而根據使用的目的來確定產品名稱，并不是根據其實際使用來命名的。其實際使用來命名的。 機械工程專業英語機械工程專業英語Lesson 19

52、Screws, fasteners and joints 第33頁/共46頁Thus it may be desirable on various occasions to use a drill to drill a hole through two sheets of steel, say, and joint them using a screw and a nut. 課文分析課文分析這樣，在各種場合用鉆頭給兩塊鋼板鉆通孔，人這樣，在各種場合用鉆頭給兩塊鋼板鉆通孔，人們就會用螺栓和螺帽來連接它們，這可能是人們們就會用螺栓和螺帽來連接它們，這可能是人們所希望的。所希望的。 There ar

53、e four forms of head most commonly used with cap screw: hexagon head, fillister head, flat head and hexagon socket head. 有帽螺釘最常用的四種螺釘頭的形式是：六角頭，有帽螺釘最常用的四種螺釘頭的形式是：六角頭，槽頭，平頭和內六角沉頭。槽頭，平頭和內六角沉頭。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第34頁/共46頁When a connection is desired which can be disa

54、ssembled without destructing the parts assembled and which is strong enough to resist both external tensile load and shear load, or a combination of these, then the simple bolted joint using hardened washers is a good solution. 課文分析課文分析當需要一個螺紋聯接即可以拆開又不破壞被聯接當需要一個螺紋聯接即可以拆開又不破壞被聯接件，而且這個聯接又要有足夠的強度以承受外拉件

55、，而且這個聯接又要有足夠的強度以承受外拉力和剪力或這兩種力的合力時，使用帶淬火墊圈力和剪力或這兩種力的合力時，使用帶淬火墊圈的簡單螺栓聯接是一個很好的解決方法。的簡單螺栓聯接是一個很好的解決方法。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第35頁/共46頁In such a joint the bolt has first been tightened to produce an initial tensile preload, after which the external tensile load and the ex

56、ternal shear load are applied. 課文分析課文分析在這種螺紋聯接中，首先把螺栓上緊以產生一預在這種螺紋聯接中，首先把螺栓上緊以產生一預緊載荷初拉力，而后施加外拉力載荷和剪切載荷。緊載荷初拉力，而后施加外拉力載荷和剪切載荷。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第36頁/共46頁The effect of the preload is to place the parts in compression for better resistance to the external tensile l

57、oad and to create friction between the parts to resist the shear load. 課文分析課文分析預載荷的作用是使被連接件處于壓應力狀態以更預載荷的作用是使被連接件處于壓應力狀態以更好地抵抗外部拉伸載荷和產生摩擦力以抵抗剪切好地抵抗外部拉伸載荷和產生摩擦力以抵抗剪切載荷。載荷。The importance of preloading of bolts cannot be overestimated. A high preload improves both the fatigue resistance of a bolted conn

58、ection and the locking effect. 螺栓預加載荷的重要性不能被過高地估計。較高預螺栓預加載荷的重要性不能被過高地估計。較高預載荷即提高螺栓聯接的抗疲勞能力又改善鎖緊作用。載荷即提高螺栓聯接的抗疲勞能力又改善鎖緊作用。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第37頁/共46頁Having learned that a high preload is very desirable in important bolted connections, we must next consider means

59、of assuring that the preload is actually developed when the parts are assembled. 課文分析課文分析已經知道：高預載荷在重要的螺栓聯接中是非常已經知道：高預載荷在重要的螺栓聯接中是非常希望的。下一步我們要考慮的是，當要裝配零件希望的。下一步我們要考慮的是，當要裝配零件時，如何確保設計情況下該預載荷的產生。時，如何確保設計情況下該預載荷的產生。 機械工程專業英語機械工程專業英語Lesson 19 Screws, fasteners and joints 第38頁/共46頁If the overall length L

60、of a bolt with cross area A can actually be measured with a micrometer when it is assembled, the bolt elongation d due to the preload F can be computed using the formula d=FL/AE, where E is the modulus of elasticity of the bolt material. 課文分析課文分析如果橫截面積為如果橫截面積為A、總長度為、總長度為L的螺栓裝配時，實的螺栓裝配時，實際上是可以用千分尺來測量