材料力學 第零章 緒 論課件

1《工程力學基礎(chǔ)》課件2課程介紹課程類別：專業(yè)必修課（雙語教學）課程代碼：BT7680-2總學時：64學;學分：4適用專業(yè)：材料科學與工程先修課程：普通物理學，材料科學基礎(chǔ)考核方式：閉卷成績評定：平時30％，期末考試70％3推薦教材：[美]J.M.蓋爾材料力學(英文版)（原書第5版）機械工業(yè)出版社2004參考書目：1、趙志崗材料力學(中學時)機械工業(yè)出版社20032、張少實新編材料力學機械工業(yè)出版社20023、岑運鷹工程力學，中國科學技術(shù)出版社，19964、范欽珊工程力學教程，高等教育出版社，199841．緒論（2學時）工程力學的任務及研究對象，變形固體的基本假設(shè)。外力與內(nèi)力、截面法與應力等概念桿件變形的基本形式。2軸向拉伸和壓縮（8學時）概念和實例，內(nèi)力、應力、變形、應變等基本概念，以及拉壓桿的強度計算，會求解簡單靜不定問題。3.剪切（8學時）剪切的概念，剪切的擠壓的實用計算，剪切胡克定律，了解剪切和擠壓的實用計算方法。4.扭轉(zhuǎn)（8學時）扭轉(zhuǎn)的概念，扭轉(zhuǎn)時的內(nèi)力，園軸扭轉(zhuǎn)時的內(nèi)力和強度計算，變形和剛度計算。著重討論扭轉(zhuǎn)應力公式的推導，園軸作簡單的強度和剛度計算。5.彎曲內(nèi)力（8學時）平面彎曲的概念，剪力和彎矩彎曲，剪力圖和彎矩圖，正應力強度條件，剪應力強度條件，梁的變形，簡單靜不定梁解法。55.彎曲內(nèi)力（8學時）平面彎曲的概念，剪力和彎矩彎曲，剪力圖和彎矩圖，正應力強度條件，剪應力強度條件，梁的變形，提高梁抗彎能力的措施，簡單靜不定梁的解法。6.組合變形與強度理論問題（8學時）組合變形的概念，彎曲與拉（壓）的組合，應力狀態(tài)分析，強度理論，彎曲和扭轉(zhuǎn)組合時的強度計算。7．應力狀態(tài)與應變狀態(tài)分析（8學時）二維應力狀態(tài)分析的數(shù)學解析法與圖形解析法，經(jīng)典強度理論，應變分析，復雜應變狀態(tài)下的應力-應變分析8.壓桿及桿系結(jié)構(gòu)的平衡穩(wěn)定性（6學時）壓桿穩(wěn)定的概念，細長壓桿的臨界力，歐拉公式的應用范圍，壓桿的穩(wěn)定計算。6

CHAPTER0

INTRODUCTION

INTRODUCTIONMechanicsofMaterials7

第零章緒論材料力學緒論8CHAPTER0INTRODUCTION

§0-1THERESEARCHOBJECTOFMECHANICSOFMATERIALS

§0-2

THETASKSOFMECHANICSOFMATERIALS ANDITSRELATIONWITHENGINEERING

§0-3THEPROPERTIESANDTHEFUNDAMENTAL ASSUMPTIONSOFTHESOLIDDEFORMABLEBODIES

§0-4

BASICTYPESOFTHEDEFORMATIONOFRODSINTRODUCTION9第零章緒論材料力學：研究物體受力后的內(nèi)在表現(xiàn)，

即，變形規(guī)律和破壞特征?！?–1

材料力學的研究對象§0–2

材料力學的任務及與工程的聯(lián)系

§0–3可變形固體的性質(zhì)及基本假設(shè)§0–4

桿件變形的基本形式緒論10LeonardoDaVincisaid:“mechanicsisamathematicparadise,becauseweacquiredmathematics'sfruithere."LeonardoDaVinciGalileoGalileiHemadeadetailedstudyonthebasicconceptsofmovementincludingthecenterofgravity,speedandaccelerationandcameupwiththerigidmathematicformulas.Especiallytheconceptofaccelerationisthemilestoneinthehistoryofmechanics.

Galileo(1564~1642)isaGermanastronomer,mechanistandphilosopher.HewasborninPisaonFeb151564anddiedonJan.81642atthesameplace.INTRODUCTION11緒論達芬奇說：“力學是數(shù)學的樂園，因為我們在這里獲得了數(shù)學的果實。”達芬奇伽利略12INTRODUCTIONHeonceinformallyproposedlawofinertia,whichestablishedthefoundationforNewtontoproposeformallythefirstlawandthesecondlaw.ItcanbesaidthatGalileoisthePioneerofNewtoninthesettlementoftheclassicalmechanics.Galileoalsobroughtupwiththelawofresultantandtheruleoftheparabolicmotionandsetuptheprincipleofrelativity.Heisthefirstscientisttomakealotofachievementsbythetelescope.Hekeptonfightingwiththeidealismandchurchphilosophyandsuggestedthatweshouldstudythelawofnaturebyspecificexperimentsandthoughtthatexperiencesarethesourceoftheory.GalileoGalilei13緒論達芬奇說：“力學是數(shù)學的樂園，因為我們在這里獲得了數(shù)學的果實?！边_芬奇伽利略14Introduction

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

Hebeganhiscreativeworkbetween1903and1906anddidresearchintheUniversityinGermanyeveryyearsupervisedbyfamousscholars.Hewasaprofessorofcollegesbetween1907and1917.HecametoAmericain1922andengagedinthestudyofmechanics.In1928,hefound“themechanicsdepartmentofASME”andheld,variouskindsofmechanicsseminarsperiodically.Hehasmanyworksonappliedmechanics.Especiallysincetheyearoflatetwentieshehaswrittenabout20books,suchas<mechanicsofMaterials>,<AdvancedMechanicsofMaterials>and<MechanicsofStructures>exceptthathehasdonesomeworkinteachingandtrainingmaters.S.PisaRussiandynamicistwithAmericannationality.HewasborninUkraineonDec.231878anddiedinGermanonMay.291972.17緒論18IntroductionHemakesgreatcontributionstotheresearchoflocaldamageandtheengineeringapplicationoffracturedynamics.Hehastrainedsomeresearchersinmechanics.Heisactiveinacademicactivitiesandtakessomepositionsbothathomeandabroad.Heisacouncilmemberofthefirstsessioncouncilconference.Hecouncilchairpersonofthesecondsessioncouncilconferenceandtheexecutivemanagerofthethirdsessioncouncilconference.HewasborninfamilyinShoucity,Anhuiprovince.NowheistheprofessorofSouthwestJiaoTongUniversity.SunXunfangisanengineeringmechanistandmechanicseducationist.Hehasengagedintheresearchoffracture,damage,fatigueandcreepofsolidmechanics.Heisthefirsttoapplyfracturedynamicstopracticeanddevelopedthemethodofanalysisinelasto-plasticfracturedynamicswithsurfacecracksandassessmentinintegrity.19緒論20§0-1THERESEARCHOBJECTSOFMECHANICSOFMATERIALS1、Structuremembers2、Classificationof structuremembersINTRODUCTIONplateOrshellbarorrodclumpbody21§0-1材料力學的研究對象1、構(gòu)件2、構(gòu)件分類緒論塊體BeamsandrodsarethemainresearchobjectsofmechanicsofmaterialsINTRODUCTION材料力學以“梁、桿”為主要研究對象緒論MoststructuresaremadeupfromthebeamsandrodsINTRODUCTION工程中多為梁、桿結(jié)構(gòu)緒論26§0-2THETASKSOFMECHANICSOFMATERIALS ANDITSRELATIONWITHENGINEERING

Strength、rigidity、stabilityINTRODUCTION27§0-2材料力學的任務及與工程的聯(lián)系強度、剛度、穩(wěn)定性緒論28INTRODUCTION29緒論30

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

材料力學的任務在滿足強度、剛度、穩(wěn)定性的要求下，以最經(jīng)濟的代價，為構(gòu)件確定合理的形狀和尺寸，選擇適宜的材料，而提供必要的理論基礎(chǔ)和計算方法。緒論32

§0-3THEPROPERTIESANDTHEFUNDAMENTAL ASSUMPTIONOFTHESOLIDDEFORMABLEBODIES

1.Continuity:Thematerialofasoliddeformablebodyiscontinuouslydistributedoveritsvolumesothattherearenotanycracks,defectsorholesetc.

2.Homogeneity:Thematerialofthesoliddeformablebodyishomogeneouslydistributedoveritsvolumesothatthesmallestelementcutfromthebodypossessesthesamespecificmechanicalpropertiesasthebody.

3.Isotropy:Themechanicalpropertiesarethesameinalldirectionsatapoint.materialwiththispropertyiscalledisotropymaterial.Materialthatthemechanicalpropertiesaredifferentinalldirectionsatapointiscalledanisotropymaterial.

4.Smalldeformations:Thedeformationsforasoliddeformablebodycausedbyexternalforcesareverysmallcomparedwiththedimensionsofthebody.Thuswhenwestudytheequilib