Unit 3 Application of Mechanics of Materials and Its Study Method
材料力学(双语)Torsion
∑m
x
= 0, T =m
T −m =0
m
m
m 3). Sign conventions for internal torque (扭矩的符号规定)： 扭矩的转向与截面外法线方向满足右手螺旋规则为正，反之为负。 8
T
x
4). Internal torque diagram(扭矩图)： 表示沿杆件轴线各横截面上扭矩变化规律的图线 ① 扭矩变化规律 ②|T|max值及其截面位置，可用于确定危险截面及强度计算
A0：Area of the circle with an average radius
16
3. 剪应力互等定理：
a dy
γ
τ´
b
∑ mz = 0
τ ⋅ t ⋅ dxdy = τ ′ ⋅ t ⋅ dxdy τ = τ ′ (a) Thus,
τ τ´
c z dx d t
τ
Formula (a) is called theorem of conjugate shearing stresses (剪应力互等定理). 该定理表明：在单元体相互垂直的两个平面上，剪应力必 然成对出现，且数值相等，两者都垂直于两平面的交线， 其方向则共同指向或共同背离该交线。 单元体的四个侧面上只有剪应力而无正应力作用，这种应 力状态称为纯剪切应力状态。
=
π
32 4 πD 4 = (1 − α ) 32
(D − d )
4 4
d (α = ) D
27
④ Distribution of the shearing stresses (应力分布)
（solid section）
（hollow section）
In engineering the members with hollow section are widely used to increase the strength, save materials and decrease the weight of structures.
新职业英语 土建英语 Unit 3
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Unit 3 Designing a Building
Reading A
Step Two: Investigate Local Conditions The design of any civil engineering structure is greatly influenced by local conditions. Even if the performance requirements are the same and the same type of structures is selected for different locations, each structure will exhibit differences in design so as to comply with the local conditions. Site elevations, foundation characteristics, water tables, immediate surroundings, and the environment as a whole are some of the local conditions that will need to be investigated.
Unit 3 Designing a Building
Warming-up
Task 2 Match the phrases with their Chinese equivalents.
1. preliminary design 2. specifications 3. comparison of drafts
Failure modes&failure theories_Mechanics of Materials
Theories of FailureFailure is generally perceived to be fracture or complete separation of a member. However, failure may also occur due to excessive deformation (elastic or inelastic) or a variety of other reasons.Failure Modes 3Excessive elasticdeformationYielding Fracture•stretch, twist, or bending •buckling •vibration •plastic deformation atroom temperature•creep at elevatedtemperatures•yield stress is theimportant design factor•sudden fracture of brittlematerials•fatigue (progressivefracture)•stress rupture at elevatedtemperatures•ultimate stress is theimportant design factorDuring the latter part of the 19th century and continuing up to the present, a number of basic failure theories were proposed and tested on a few materials.1Most of the theories were based on the assumption that failure occurs when some physical variable such as stress, strain, or energy reaches a limiting value.Deformation:•Elastic deformation is temporary (reversible) and involves bond stretching.•Plastic deformation is permanent (irreversible), and involves bond breaking.•Fracture is catastrophic./matse81/Spring%202003/LectureNotes/ Classification System for Mechanical Failure Modes 4Manifestations of Failure elastic deformationplastic deformationrupture or fracturematerial change Failure-Inducing AgentsCommonly Observed Mechanical Failure Modes Force and/or Temperature-Induced Elastic DeformationYieldingBrinnellingDuctile RuptureBrittle FractureFatigueforcetimetemperaturereactive environmentFailure Locationsbody typesurface type CorrosionWearImpactFrettingCreepThermal RelaxationStress RuptureThermal ShockGalling and SeizureSpallingRadiation DamageBucklingCreep BucklingStress CorrosionCorrosion WearCorrosion Fatigue Combined Creep and FatigueStress TheoriesMaximum Principal Stress Theory (Rankine, Lamé)Applied satisfactorily to many brittle materials, the theory is based on a limiting normal stress. Failure occurs when the normal stress reaches a specified upper limit.1Failure is predicted when either ofthe principal stresses, σ1or σ2,equals or exceeds the yield strength,σyp , of the material.3σ1< σypσ2< σypExamplesClick on image for full size.Maximum Shear Stress Theory (Tresca, Guest, Coulomb)Applied satisfactorily to ductile materials, the theory is based on the concept of limiting shearing stress at which failure occurs.1Failure by yielding in a more complicated loading situation is assumed to occur when the maximum shearing stress in the material reaches a value equal to the maximum shearing stress in a tension test at yield.This yield criterion gives good agreement with experimental results for ductile materials; because of its simplicity, it is the most often used yield theory.2The main objection to this theory is that it ignores the possible effect of the intermediate principal stress, σ2. However, only one other theory, the maximum distortional strain energy theory, predicts yielding better than does the Tresca theory, and the differences between the two theories are rarely more than 15%.Failure is predicted when any of the three shear stresses corresponding to the principal stresses, σ1,2, equals or exceeds the shear stresscorresponding to the yield strength, σyp , of the material in uniaxial tension or compression.3Maximum Octahedral Shearing Stress TheoryFailure by yielding in a more complicated loading situation is assumed to occur when the octahedral shearing stress in the material reaches a value equal to the maximum octahedral shearing stress in a tension test at yield.Plane stress caseUniaxial stress caseNote: This theory gives the same results as the maximum distortion energy theory.Strain TheoriesMaximum Principal Strain Theory (Saint-Venant )The theory is based on the assumption that inelastic behavior or failure is governed by a specified maximum normal strain.1 Failure will occur at a particular part in a body subjected to an arbitrary state of strain when the normal strain reaches a limiting level.Failure is predicted when either of the principal strains, resulting from the principal stresses, σ1,2, equals or exceeds the maximum straincorresponding to the yield strength, σyp , of the material in uniaxial tension or compression.3 σ1 - ν(σ2 + σ3) < σypTotal Strain Energy Theory (Beltrami-Haigh)Applicable to many types of materials, the theory predicts failure or inelastic action at a point when the strain energy per unit volume exceeds a specified limit.1Failure is predicted when the total strain energy associated with the principal stresses, σ1,2, equals or exceeds the total strain energy corresponding to thatfor the yield strength, σyp , of the material in uniaxial tension or compression.3 σ12 + σ22 +σ32 -2ν(σ1σ2 + σ2σ3 + σ1σ3) < σyp 2Maximum Distortion Energy Theory (Huber-Henky-von Mises )The theory is based on a limiting energy of distortion, i.e. energy associated with shear strains.1Strain energy can be separated into energy associated with volume change and energy associated with distortion of the body. The maximum distortion energy failure theory assumes failure by yielding in a more complicated loading situation to occur when the distortion energy in the material reaches the same value as in a tension test at yield.This theory provides the best agreement between experiment and theory and, along the Tresca theory, is very widely used today.2Note: This theory gives the same results as the octahedral shear stress theory.Failure is predicted when the distortional energy associated with the principal stresses, σ1,2, equals or exceeds the distortional energy corresponding to thatfor the yield strength, σyp , of the material in uniaxial tension or compression.3 0.5 ( (σ1 - σ2)2 + (σ2 - σ3)2 + (σ3 - σ1)2) < σyp 2SummaryOf the failure criteria, the Tresca is the most conservative for all materials, the von Mises the most representative for ductile materials, and the Rankine the best fit for brittle materials.3Laminated-Composite Failure EnvelopesMore on failure theoriesBelow is a summary of two of most popular theories of failure applied to a simple uniaxial stress state and to a pure shear stress state.Failure CriteriaReferences1. Mechanics of Wood and Wood Composites, by J. Bodig & B.A. Jayne, KriegerPublishing, 1993, pp. 314-5.2. The Science and Technology of Civil Engineering Materials, by J.F. Young, S.Mindess, R.J. Gray, & A. Bentur, Prentice Hall, 1998, pp. 115-7.3. "Failure Prediction and Avoidance," Experimental Stress Analysis Notebook,Issue 22, Dec. 1993, Measurements Group, pp. 6-11.4. Failure of Materials in Mechanical Design - Analysis Prediction Prevention, byJ. A. Collins, John Wiley and Sons, 1981, pp. 6-8.。
土木工程专业英语-单词
土木工程专业英语Ch 1Ch 2Ch 3Ch 4Ch 5 Ch 6Ch 7Ch 8Ch 9Ch 10 Ch 13Ch 17Ch 33Ch 39Ch 47Ch 1 Introduction to Mechanics of MaterialsWords and Expressionstorque扭矩, 转矩；扭转impose将……强加于，施加，强使composite合成的，复合的；复合材料，合成物sag下垂，凹陷deflect偏转，弯曲，下垂，倾斜excessively过多地，极度地misalignment不重合，安装误差，调整不当plaster灰泥，灰浆，涂层stiffness刚度，刚性，坚硬性constructor设计者，建造者，施工人员precedent先例，惯例；在先的，领先的contradistinction对比，截然相反，区别in contradistinction to M与M截然不同，不同于Mrational合理的，理性的，理论的，有理解能力的tension张力，拉力，拉伸；拉紧compression压缩，压力，凝缩indelible不能消除的，不可磨灭的，难忘的blended混合的，混杂的postulate假定，设定，先决条件，基本原理presume假定，推测，以为visualize观察，检验，（使）具体[形象，直观]化，设想，想象diagrammatic图解的，图表的，概略的，轮廓的diagrammatic sketch示意图dividend股息，利息，收获aerodynamic空气动力的，气动的Ch 2 Overview of Engineering MechanicsWords and Expressionsceramics陶瓷，陶瓷材料perceive感觉，觉察，发觉，领会，理解，看出inertia惯性，惯量，惰性lifetime使用寿命，使用期限，持续时间，生存期interactive相互作用的，相互影响的，交互的iterative反复的，迭代的，重复的durability耐久性，持久性，耐用期限pinpoint针尖；极精确的，细致的；准确定位，正确指出，确认，强调evolve开展，发展，研究出，（结果试验研究等）得出substance物质，材料，内容，要点，梗概lucrative可获得的，赚钱的，有利的statics静力学strength of materials材料力学deformation变形，形变，畸变dynamic动力的，动力学的，冲击的appreciate正确评价，理解，体会到，懂得(be) inherent in 为……所固有，是……的固有性质false假的，不真实的，似是而非的render提出，给予，描绘，表现tractable易处理的，易加工的prohibitive禁止的，抑制的，起阻止作用的meld融合，汇合、组合，合并，归并order of magnitude数量级influx流入，涌进，汇集，灌注Ch 3 Stress-Strain Relationship of MaterialsWords and Expressions distortion变形，挠曲，扭曲，歪曲thousandth第一千的，千分之一的boring machine镗床boom吊杆，起重杆，悬臂；繁荣，兴旺dragline拉铲挖土机，挖掘斗gray cast iron灰铸铁concrete具体的，坚实的，混凝土的；混凝土modulus of elasticity弹性模量rigidity刚性，刚度，稳定性slip滑动，滑移，打滑creep爬行，蠕变，徐变yield产生，屈服于；屈服，弯曲rupture破裂，断裂，破坏Ch 4 Stress Limits in DesignWords and Expressions withstand抵抗，经受，耐得住，顶得住springy有弹性的，似弹簧的diving跳水的，潜水，潜水的subjective主观的；主观事物turbulent骚动的，湍流的，汹涌的decimal小数的，以十为基础的；小数slip滑动，疏忽，遗漏tolerance公差，容许极限，容许间隙coffee break休息，喝咖啡的时间（通常为十五分钟）crash崩溃，毁损lubricate润滑，起润滑作用safety factor安全系数diligence勤奋，勤劳，努力，注意enviable可羡慕的instill浸染，逐渐灌输humility谦卑ethical伦理的，道德的，合乎道德的legal法律的，合法的，法定的Ch 5 Load ClassificationWords and Expressions load carry capacity承载能力unprecedented无先例的，史无前例的，崭新的terminology专用名词，术语，词汇sustain支撑，支持，持续，保持helical螺旋面，螺线，螺旋状的helical spring螺旋形弹簧concentrated集中的，浓缩的distribute分布，分发，散布resultant合成的，综合的，总的；合力centroid矩心，质心，重心，行心torsional扭的，转的bending挠曲，弯曲，扭弯flexural弯曲的，挠性的couple对，爽，力偶，力矩Ch 6 Testing of MaterialsWords and Expressions destruction破坏，破裂，毁坏non-load-bearing非承重，不承重durability耐久性，持久性，使用年限brittle脆的，脆性的ASTM美国材料试验学会BSI英国标准学会SAA澳大利亚标准学会passage通过，行程，一段，一节plastic deformation塑性变形minute微小的，细微的，精密的，细致的moisture content含水量timber木材，木料；用木材建造veracity诚实，真实性，准确性，精确性ready-mixed concrete预拌混凝土building contractor建筑承包商hydraulic press水压机grading分等，分级，分类，级配fatigue疲劳ductility可延展性，延度，韧性toughness韧性，韧度stress-strain curve应力-应变曲线deduce推断，推定，导出，演绎Ch 7 Durability of ConcreteWords and Expressions durable耐久的，经久的，永久性的；耐用的物品durability耐久性，经久性，耐用年限chloride氯化物，漂白粉sulphate硫酸盐alkali碱，碱性，强碱absorption吸收，吸取，吸水性permeability渗透性，透气性，渗透deterioration变坏，变质，损坏，损伤weathering风化（作用，层），自然老化，大气侵蚀disruptive分裂的，摧毁的，破坏的thaw使融化，解冻，熔化entrain携带，传输，使（空气）以气泡状存于混凝土中，产生leaching浸出，浸析作用，浸滤，溶析carbonation碳化作用，碳酸盐化blasting破裂，吹风，气流加速运动，喷砂attrition磨损，磨耗，损耗hydraulic水力的，水压的；水力cavity空腔，空穴，孔穴，洞穴cavitation气蚀，空蚀，空化作用impermeability不渗透性，防水性，气密性hydraulic structure水工建筑物pervious透水的，透光的，有孔的，能通过的aggregate集料，骨料，总计，合计homogeneous均质的，均匀的，单相的compact紧密的，密实的；压实，捣实kerb路缘，道牙，建筑物上的边饰air-entrained concrete加气混凝土Ch 8 Durability of Building MaterialsWords and Expressionsglaze釉面，珐琅质，上釉，半透明薄涂层stainless steel不锈钢galvanize电镀，镀锌于gutter排水沟，水槽，漏斗plaster灰泥，灰浆humidity湿度，湿气，水分含量thaw融化，解冻，使缓和；温暖气候porous多孔的，疏松的，有孔的，可透水的spectrum谱，频谱，领域，范围，各种各样infrared红外的，产生红外辐射的；红外线ultraviolet紫外的，紫外线的；紫外线辐射radiation发射，辐射，照射，放射线gravel砾石，沙砾，石子，卵石fade衰减，（使）褪色，逐渐消失anodized受过阳极化处理的（金属表面）hydrate水合物；（使）成水合物reinforcement加强，加固，钢筋，构架spall剥落，散裂，裂开；裂片，碎片carpet地毯，磨耗层；铺毡，铺毯，铺层erosion侵蚀，腐蚀，冲刷，冲蚀abrasion磨损，磨耗，磨蚀quarry方形砖，方形瓦domestic家庭的，民用的，地方的，局部的passive被动的，消极的，无源的eddy（水，风，尘等的）涡流，漩涡运动Ch 9 Reinforcing Steels for ConcreteWords and Expressions reinforcing steel钢筋reinforced concrete钢筋混凝土reinforcing bar钢筋longitudinal长度的，纵向的，轴向的dispose处置，安排，配置，布置incline倾斜，弄斜，有……倾向moment力矩，弯矩，转矩，动量bond结合，结合力，粘合力，握裹；结合，粘结interlock连动，连结，结合，相互关系forestall阻止，预防，占先，先下手corrosion腐蚀，侵蚀，锈impair削弱，损害，减少embed放入，埋入，埋置，嵌入prestressing steel预应力钢筋rebar = reinforcing bar 钢筋splice拼接，联接，连接，接合；拼接，接头congestion充满，拥挤，密集form模板ACI美国混凝土学会(American Concrete Institute)Code法规，规程，规范Galvanize电镀，镀锌于Ch 10 ReinforcementWords and Expressions undue过度的，过分的，不相称的，不适当的BS英国标准(British Standard)bending machine弯筋机mandrel芯棒，心轴，紧轴jig夹具，夹紧装置，模具dowel榫钉，夹缝钉，暗销，传力杆，合缝钢条，外伸的短钢筋wire clip钢丝剪interweave使交织，交叉，织进，使混杂prefix词头，字首，前缀；加在……前头reference number参考号数formwork样板，模板，模壳，支模mill scale热轧钢表面的氧化皮spacer隔离物，垫片，隔板，定位架，横柱clip夹子，支架，夹板，剪刀；夹住，钳劳，固定slab板，块，楼板cradle吊架，托架，支架chair椅子，托架，座板，垫板spall剥落，散裂，裂开，分裂；裂片；碎片mild steel低碳钢comply同意，遵守，履行，根据tack图钉，平头钉，点焊焊缝；定位焊，绑住Ch 13 Design of Simple StructuresWords and Expressions code法典，法规，规程，规范，代码ordinance规格，条例，法令，布告shell壳，壳体，外壳skeleton骨架，框架（的）suspended structure悬吊结构arena圆剧场，表演场，活动舞台feasibility可行性，可能性，现实性joist梁，搁栅，桁条diaphragm膜，隔膜，隔板，遮光板，遮水板pedestrian行人，步行者；行人的，步行的deck bridge上承桥，跨线桥through bridge下承桥chord弦，弦杆，弦长bracing拉条，撑条，支撑，支柱pony小型的，矮的web-girder腹板大梁box-girder箱梁geological地质的，地质学的geographical地理学的，地理上的，地区的aesthetic美术的，美学的Ch 17 Loading ConditionsWords and Expressions concentrated集中的，浓缩的impose将……强加于，强使，施加，产生影响acceleration加速度，加速度值stochastic随机的，不确定的，偶然的provision预备，措施，规定，条款erection安装，装配，建设prestress预加应力于，预应力，预拉伸plaster灰泥，墁灰，墙粉，灰浆merchandise商品，货物seismic地震的，与地震有关的collision碰撞，冲突single load集中荷载Ch 33 Tall Building StructureWords and Expressions civilization文明，开化，文化ecclesiastical基督教会的，教士的landmark路标，界标，界桩，里程碑prestige威信，声誉mobility可动性，机动性，流动性，迁移topographical地形的，地形测量的，地志的subservient辅助性的，只作为一种手段的tax税，负担，压力；使负重担，使受压力ingenuity巧妙，机敏，创造性，才干shear wall core剪力墙筒体parasitic派生的，附加的radical根本的，基本的，主要的erection树立，建立，安装，建设prefabrication预制，预制品slip-formwork滑膜crane起重机；用起重机起吊sprawl蔓生，展开，散开，扩展，（无计划）延伸codify编成法典，编纂，整理Ch 39 FoundationsWords and Expressions superstructure上层结构，上部结构earth fill土堤substructure下部结构，下层建筑，基础工事demarcation分界线，标界，划界，区分demarcation line界线，边界线interfacing交界的，相邻的，相互联系的；接口技术dilemma困境，进退两难statute法令，法规，规定，条例conservative保守的，有裕量的；谨慎的sanitary环境卫生的，清洁的sanitary fill垃圾堆积场reclamation废料回收，改造，垦殖，填筑disposal处理，整理，清理，处置client委托人，当事人，买方，买主boring钻探，打眼，地质钻孔试验mat席，垫，垫块，钢筋网，垫层caisson沉箱soil profile土壤剖面，土层剖面Ch 47 BridgesWords and Expressions esthetically美学地，审美地cable-stayed斜拉的，张拉的girder梁，桁，梁杆cast-in-place现场浇注的，就地浇注的AASHTO美国洲际公路及运输工作者协会AREA美国铁路工程师协会crossing交叉，十字路口，交叉建筑物asphalt沥青，柏油，铺路用沥青混合料pier桥墩elevated高架的，高的；高架铁路viaduct高架桥，跨线桥clearance间隙，净空，间距，距离segment部分，段。
Unit 3 Mechanical Properties of Materials
category [ˈkæti əri] n. 类型，部门，种 ɡ 类，类别 acidity [əˈs ɪdɪti:] n. 酸性 layman [ˈleimən n.门外汉，外行；俗人； 一般信徒 decay [diˈkei] vt.& vi.（使）腐烂，腐 朽
axis [ˈæksis] n.轴，轴线
翻译的基本技巧-词ห้องสมุดไป่ตู้的引申
The records have been brought up to date. 记录已经过修改，包括最新的数字。 —— up to date 的原意是“最新的”。 Laptop computers are now available. 现在已经有了笔记本电脑。 ——available的原意是“可利用的”。 Robotics is certainly one of the most significant scientific developments of moden times.
Unit 3 Mechanical Properties of Materials
mechanical [miˈkænikəl] adj.机械的， 机械学的；呆板的；体力的；手工操作的 property [ˈpr ɔpəti] n. 特性，属性；财产， 地产 specific gravity [spiˈsifik ˈ viti]比重 ɡræ moisture [ˈm ɔistʃə] n. 水分；湿气；潮 湿；降雨量 content [ˈk ɔntent] n. 内容；（书等的） 目录；满足；容量
机器人技术当然是现代意义最大的科学成就 之一。 ——development的原意是“发展”。 The advantages of nano-structured materials do not end here. ——do not end here的原意是“不在这里终 止” 纳米材料的优点，不仅仅如此。 The twentieth century saw the greatest scientific achievements in human history. 20世纪取得了人类历史上最伟大的科学成就。
机械工程英语翻译Unit 3
Unit 3数控编程Unit 3 Programming for Numerical ControlA program for numerical control consists of a sequence of directions that causes an NC machine to carry out a certain operation, machining being the most commonly used process. Programming for NC may be done by an internal programming department, on the shop floor, or purchased from an outside source. Also, programming may be done manually or with computer assistance.数控编程由一系列方向构成，这些方向导致数控车床执行某种操作，加工是最常用的进程。
数控车床编程由内部编程部门来完成，在车间里，或者从外部源购买。
编程还可以手动或者在计算机辅助下来完成。
The program contains instructions and commands. Geometric instructions pertain to relative movements between the tool and the workpiece. Processing instructions pertain to spindle speeds, feeds, tools, and so on. Travel instructions pertain to the type of interpolation and slow or rapid movements of the tool or worktable. Switching commands pertain to on/off position for coolant supplies, spindle rotation, direction of spindle rotation, tool changes, workpiece feeding, clamping, and so on.程序包括指令和命令。
《化学工程与工艺专业英语》课文翻译-Unit 3 Typical Activities of Chemical Engineers
Unit 3 Typical Activities of Chemical Engineers化学工程师的例行工作The classical role of the chemical engineer is to take the discoveries made by the chemist in the laboratory and develop them into money--making, commercial-scale chemical processes. The chemist works in test tubes and Parr bombs with very small quantities of reactants and products (e.g., 100 ml), usually running “batch”, constant-temperature experiments. Reactants are placed in a small container in a constant temperature bath. A catalyst is added and the reactions proceed with time. Samples are taken at appropriate intervals to follow the consumption of the reactants and the production of products as time progresses.化学工程师经典的角色是把化学家在实验室里的发现拿来并发展成为能赚钱的、商业规模的化学过程。
化学家用少量的反应物在试管和派式氧弹中反应相应得到少量的生成物，所进行的通常是间歇性的恒温下的实验，反应物放在很小的置于恒温水槽的容器中，加点催化剂，反应继续进行，随时间推移，反应物被消耗，并有生成物产生，产物在合适的间歇时间获得。
Unit3WritingJobApplicationLetter
Unit3WritingJobApplicationLetterUnit3 Writing Job Application LetterI. Review the different styles of personal letter and business letterUsurally, there are eight parts in a letter. They are sender’s address, date receiver’s address, opening, body, closing, signature and title. If necessary, we should include encloure. How to orgnize a letter? There are there styles: block styles; modified block style and indented style.II. Objectives:Students will be able to1.understand the main idea and the structure of the text2.Learn how to write a job application letter and the characteristic of theapplication letter.3.Grasp some key language points in the text.III. leading-inEvery college graduate is sure, sooner or later, to meet the greatest challenge in their life: looking for a job that can earn them a livelihood. Before doing this, they have to prepare application letters. The process of preparation is time-consuming, and, for many of them, might not be pleasant at all. But they have to face it. Then, how to write a job application letter? And what are the main points we should pay attention to when writing an application letter? With the two questions in our minds; let us look at the text.IV. Analyze the text1. Detailed study of the textThe purpose of an application letter is to persuade people toread your resume, so how to write it will directly reflect how suitable you for the job. An application letter should be brief, no more than one page in length. It should be easy to read and include only the necessary information. Here is a most effective method of writing job application letter, and it is outlined below.1). addessing job application letters.There are many different styles for you to choose. What style you choose is really a matter of personal preference. However, somewhere on the top, whether on the right-hand side or left-hand side, you should have your address and the date. Then on the left hand side, you should include the name of the person you are writing to. Y ou should write his/her title, company name, address, and position reference number.Here you should pay attention to an important point that is you should make sure you do not make any mistakes in spelling their name. Such a mistake will make a poor first impression on the reader. The reader may be your boss in the future. And the bad impression is difficult to change.2). the introductory paragraphAfter your opening salutation, the first paragraph should simply state why you are writing to him/her. If it is an advertised position, please mention the position title and where it was advertised. If you are making phone calls or playing visit to the company for a job without an appointment made in advance, then you should make it clear that you are applying for any current or future employment opportunities.An easy way to state this paragraph is with the following statement: “please find encoused my resume, which I amf orwarding to you as an application for the position of…”3). the main bodyAfter introductory paragraph, there is main body. The main body of the letter should be two to three paragraph at most. Here is where you illustrate what you have to offer and why he/she should read your resume. Analyze your career and summarize it in a few sentences. It is important to be selective,highlighting things like what you are specialize in, or how many years in the industry you might have. The first part should direst the reader to your resume, pointing out some unique points that you might have.The next part of the body should be a brief description of you personal skills. It is a good ideato read the advertisement and use their specification as a target. For example, if the company is asking for someone with good communication skills, then make sure you mention something to that effect. If it is perhaps, leadership skills that are valued then write about these.4). closing paragraphAfter the main body, there should be closing paragraph. This is where you ask for an interview. Because getting a interview is the first step you can really get the position you have always wanted. Y ou should also state where and how the employer can reach you, and express thanks for giving you the opportunity to apply.Finish the letter by adding a closing remark, either “yours sincerely”“yours faithfully”or whatever you feel comfortable with, as long as it obeys the general principles of good letter-writing. Leave a few space for your signature, and then place your full name.Before you mail the application letter, read it over again, making sure that it is perfect. Y ou have to ensure that the letter:1)is not too long2)has no errors3)has responded to the job requirements and4)flows well and is easy to readY ou may have read and revise the letter many times before you are satisfied with it. However, when you finally send this letter, it will be an invitation for others to read more about you in your resume, and in turn, to get an interview for you, hopefully.2. the character of a job application letter1) a job application should be brief and should generally be one page in length2) its purpose is to persuade the reader to see your resume3) it should appeal to its reader and show your cofidence in your ability to do thejob but don’t go too far.4) its tone should be friendly and confident5) never beg for the job.6) do remember to ask for an interview in your letter.3 text structureThis text is an expositiry essay, which explains how to write an appropriate jobapplication letter. The whole text is made up of three parts: introduction, body and conclusion.4 some important language points in the text1). No more than: only; at mostEg: No more than 3,000 college graduates are allowed to go abroad every year.每年至多允许3000名大学毕业生出国。
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Application of Mechanics of Materials and Its Study Method
材料力学应用和学习方法Unit 3
Paragraph 1
physical size实际尺寸
pressure vessel 压力容器
Adequate: enough, suitable
plaster 灰泥、石膏
slender 细长
buckling 屈曲
Configuration 构形 T orque 扭矩
Aerodynamic 空气动力学 deflect 偏离
sag 下垂
Misalignment ？error manufacturing equipment 制造设备
He was best known for developing Coulomb's law, the definition of the electrostatic force of attraction and repulsion. The SI unit of electric charge, the coulomb, was named after him.
21 June 1781 –25
when a sample object is stretched (or squeezed), to an
extension (or contraction) in the direction of the applied
load, it corresponds a contraction (or extension) in a
direction perpendicular to the applied load. The ratio
formulated the general theory of elasticity in a mathematically usable form (1821). His name is one of the 72 names inscribed on the formulated the general theory of elasticity in a mathematically usable form (1821), making it available to the field of construction with sufficient accuracy for the first time. In 1819 he succeeded in determining the zero line of mechanical stress, finally correcting
Adhémar Jean Claude Barré de Saint-Venant, August 23, effects of two different but statically equivalent loads
was a French mathematician who was an early pioneer
of analysis
Cauchy stress tensor。