材料力学 第零章 绪 论课件

1《工程力学基础》课件2课程介绍课程类别：专业必修课（双语教学）课程代码：BT7680-2总学时：64学;学分：4适用专业：材料科学与工程先修课程：普通物理学，材料科学基础考核方式：闭卷成绩评定：平时30％，期末考试70％3推荐教材：[美]J.M.盖尔材料力学(英文版)（原书第5版）机械工业出版社2004参考书目：1、赵志岗材料力学(中学时)机械工业出版社20032、张少实新编材料力学机械工业出版社20023、岑运鹰工程力学，中国科学技术出版社，19964、范钦珊工程力学教程，高等教育出版社，199841．绪论（2学时）工程力学的任务及研究对象，变形固体的基本假设。外力与内力、截面法与应力等概念杆件变形的基本形式。2轴向拉伸和压缩（8学时）概念和实例，内力、应力、变形、应变等基本概念，以及拉压杆的强度计算，会求解简单静不定问题。3.剪切（8学时）剪切的概念，剪切的挤压的实用计算，剪切胡克定律，了解剪切和挤压的实用计算方法。4.扭转（8学时）扭转的概念，扭转时的内力，园轴扭转时的内力和强度计算，变形和刚度计算。着重讨论扭转应力公式的推导，园轴作简单的强度和刚度计算。5.弯曲内力（8学时）平面弯曲的概念，剪力和弯矩弯曲，剪力图和弯矩图，正应力强度条件，剪应力强度条件，梁的变形，简单静不定梁解法。55.弯曲内力（8学时）平面弯曲的概念，剪力和弯矩弯曲，剪力图和弯矩图，正应力强度条件，剪应力强度条件，梁的变形，提高梁抗弯能力的措施，简单静不定梁的解法。6.组合变形与强度理论问题（8学时）组合变形的概念，弯曲与拉（压）的组合，应力状态分析，强度理论，弯曲和扭转组合时的强度计算。7．应力状态与应变状态分析（8学时）二维应力状态分析的数学解析法与图形解析法，经典强度理论，应变分析，复杂应变状态下的应力-应变分析8.压杆及杆系结构的平衡稳定性（6学时）压杆稳定的概念，细长压杆的临界力，欧拉公式的应用范围，压杆的稳定计算。6

CHAPTER0

INTRODUCTION

INTRODUCTIONMechanicsofMaterials7

第零章绪论材料力学绪论8CHAPTER0INTRODUCTION

§0-1THERESEARCHOBJECTOFMECHANICSOFMATERIALS

§0-2

THETASKSOFMECHANICSOFMATERIALS ANDITSRELATIONWITHENGINEERING

§0-3THEPROPERTIESANDTHEFUNDAMENTAL ASSUMPTIONSOFTHESOLIDDEFORMABLEBODIES

§0-4

BASICTYPESOFTHEDEFORMATIONOFRODSINTRODUCTION9第零章绪论材料力学：研究物体受力后的内在表现，

即，变形规律和破坏特征。§0–1

材料力学的研究对象§0–2

材料力学的任务及与工程的联系

§0–3可变形固体的性质及基本假设§0–4

杆件变形的基本形式绪论10LeonardoDaVincisaid:“mechanicsisamathematicparadise,becauseweacquiredmathematics'sfruithere."LeonardoDaVinciGalileoGalileiHemadeadetailedstudyonthebasicconceptsofmovementincludingthecenterofgravity,speedandaccelerationandcameupwiththerigidmathematicformulas.Especiallytheconceptofaccelerationisthemilestoneinthehistoryofmechanics.

Galileo(1564~1642)isaGermanastronomer,mechanistandphilosopher.HewasborninPisaonFeb151564anddiedonJan.81642atthesameplace.INTRODUCTION11绪论达芬奇说：“力学是数学的乐园，因为我们在这里获得了数学的果实。”达芬奇伽利略12INTRODUCTIONHeonceinformallyproposedlawofinertia,whichestablishedthefoundationforNewtontoproposeformallythefirstlawandthesecondlaw.ItcanbesaidthatGalileoisthePioneerofNewtoninthesettlementoftheclassicalmechanics.Galileoalsobroughtupwiththelawofresultantandtheruleoftheparabolicmotionandsetuptheprincipleofrelativity.Heisthefirstscientisttomakealotofachievementsbythetelescope.Hekeptonfightingwiththeidealismandchurchphilosophyandsuggestedthatweshouldstudythelawofnaturebyspecificexperimentsandthoughtthatexperiencesarethesourceoftheory.GalileoGalilei13绪论达芬奇说：“力学是数学的乐园，因为我们在这里获得了数学的果实。”达芬奇伽利略14Introduction

Herearehiscontributionstomechanics:hemadeafurtherstudyonthebasisofGalileoandotherpeopleandconcludedthethreeprinciplesofobjects’movementandmadeafirmfoundationformechanics.Heisthediscovererofthegravitationlawandsetupthetheoreticalsystemoftheclassicalmechanics.Healsomadeprofoundcontributionstothefieldofmathematics,opticsandastronomy.<Themaththeoryofnaturalphilosophy>ishismostimportantwork.Heconcludedmanyimportantdiscoveriesandstudyresultsinallhislifeinthebook.IsaacNewton(1642~1727)isagreatBritishphysicist,mathematicianandastronomer.HewasborninafamilyofpeasantsinLincolnonDec251624anddiedofKidneystoneinLondononMar201727.15绪论16Introduction

Hebeganhiscreativeworkbetween1903and1906anddidresearchintheUniversityinGermanyeveryyearsupervisedbyfamousscholars.Hewasaprofessorofcollegesbetween1907and1917.HecametoAmericain1922andengagedinthestudyofmechanics.In1928,hefound“themechanicsdepartmentofASME”andheld,variouskindsofmechanicsseminarsperiodically.Hehasmanyworksonappliedmechanics.Especiallysincetheyearoflatetwentieshehaswrittenabout20books,suchas<mechanicsofMaterials>,<AdvancedMechanicsofMaterials>and<MechanicsofStructures>exceptthathehasdonesomeworkinteachingandtrainingmaters.S.PisaRussiandynamicistwithAmericannationality.HewasborninUkraineonDec.231878anddiedinGermanonMay.291972.17绪论18IntroductionHemakesgreatcontributionstotheresearchoflocaldamageandtheengineeringapplicationoffracturedynamics.Hehastrainedsomeresearchersinmechanics.Heisactiveinacademicactivitiesandtakessomepositionsbothathomeandabroad.Heisacouncilmemberofthefirstsessioncouncilconference.Hecouncilchairpersonofthesecondsessioncouncilconferenceandtheexecutivemanagerofthethirdsessioncouncilconference.HewasborninfamilyinShoucity,Anhuiprovince.NowheistheprofessorofSouthwestJiaoTongUniversity.SunXunfangisanengineeringmechanistandmechanicseducationist.Hehasengagedintheresearchoffracture,damage,fatigueandcreepofsolidmechanics.Heisthefirsttoapplyfracturedynamicstopracticeanddevelopedthemethodofanalysisinelasto-plasticfracturedynamicswithsurfacecracksandassessmentinintegrity.19绪论20§0-1THERESEARCHOBJECTSOFMECHANICSOFMATERIALS1、Structuremembers2、Classificationof structuremembersINTRODUCTIONplateOrshellbarorrodclumpbody21§0-1材料力学的研究对象1、构件2、构件分类绪论块体BeamsandrodsarethemainresearchobjectsofmechanicsofmaterialsINTRODUCTION材料力学以“梁、杆”为主要研究对象绪论MoststructuresaremadeupfromthebeamsandrodsINTRODUCTION工程中多为梁、杆结构绪论26§0-2THETASKSOFMECHANICSOFMATERIALS ANDITSRELATIONWITHENGINEERING

Strength、rigidity、stabilityINTRODUCTION27§0-2材料力学的任务及与工程的联系强度、刚度、稳定性绪论28INTRODUCTION29绪论30

ThetasksofmechanicsofmaterialsUndertherequestthatthestrength,rigidity,stabilityaresatisfied,offerthenecessarytheoreticalfoundationandcalculationmethodfordeterminingreasonableshapesanddimensions,choosingpropermaterialsforthecomponentsatthemosteconomicprice.,INTRODUCTION31

材料力学的任务在满足强度、刚度、稳定性的要求下，以最经济的代价，为构件确定合理的形状和尺寸，选择适宜的材料，而提供必要的理论基础和计算方法。绪论32

§0-3THEPROPERTIESANDTHEFUNDAMENTAL ASSUMPTIONOFTHESOLIDDEFORMABLEBODIES

1.Continuity:Thematerialofasoliddeformablebodyiscontinuouslydistributedoveritsvolumesothattherearenotanycracks,defectsorholesetc.

2.Homogeneity:Thematerialofthesoliddeformablebodyishomogeneouslydistributedoveritsvolumesothatthesmallestelementcutfromthebodypossessesthesamespecificmechanicalpropertiesasthebody.

3.Isotropy:Themechanicalpropertiesarethesameinalldirectionsatapoint.materialwiththispropertyiscalledisotropymaterial.Materialthatthemechanicalpropertiesaredifferentinalldirectionsatapointiscalledanisotropymaterial.

4.Smalldeformations:Thedeformationsforasoliddeformablebodycausedbyexternalforcesareverysmallcomparedwiththedimensionsofthebody.Thuswhenwestudytheequilib