材料力學(xué) 第零章 緒 論課件

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

CHAPTER0

INTRODUCTION

INTRODUCTIONMechanicsofMaterials7

第零章緒論材料力學(xué)緒論8CHAPTER0INTRODUCTION

§0-1THERESEARCHOBJECTOFMECHANICSOFMATERIALS

§0-2

THETASKSOFMECHANICSOFMATERIALS ANDITSRELATIONWITHENGINEERING

§0-3THEPROPERTIESANDTHEFUNDAMENTAL ASSUMPTIONSOFTHESOLIDDEFORMABLEBODIES

§0-4

BASICTYPESOFTHEDEFORMATIONOFRODSINTRODUCTION9第零章緒論材料力學(xué)：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(xué)的研究對(duì)象§0–2

材料力學(xué)的任務(wù)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(dá)芬奇說(shuō)：“力學(xué)是數(shù)學(xué)的樂(lè)園，因?yàn)槲覀冊(cè)谶@里獲得了數(shù)學(xué)的果實(shí)。”達(dá)芬奇伽利略12INTRODUCTIONHeonceinformallyproposedlawofinertia,whichestablishedthefoundationforNewtontoproposeformallythefirstlawandthesecondlaw.ItcanbesaidthatGalileoisthePioneerofNewtoninthesettlementoftheclassicalmechanics.Galileoalsobroughtupwiththelawofresultantandtheruleoftheparabolicmotionandsetuptheprincipleofrelativity.Heisthefirstscientisttomakealotofachievementsbythetelescope.Hekeptonfightingwiththeidealismandchurchphilosophyandsuggestedthatweshouldstudythelawofnaturebyspecificexperimentsandthoughtthatexperiencesarethesourceoftheory.GalileoGalilei13緒論達(dá)芬奇說(shuō)：“力學(xué)是數(shù)學(xué)的樂(lè)園，因?yàn)槲覀冊(cè)谶@里獲得了數(shù)學(xué)的果實(shí)?！边_(dá)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(xué)的研究對(duì)象1、構(gòu)件2、構(gòu)件分類緒論塊體BeamsandrodsarethemainresearchobjectsofmechanicsofmaterialsINTRODUCTION材料力學(xué)以“梁、桿”為主要研究對(duì)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(xué)的任務(wù)及與工程的聯(lián)系強(qiáng)度、剛度、穩(wěn)定性緒論28INTRODUCTION29緒論30

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

材料力學(xué)的任務(wù)在滿足強(qiáng)度、剛度、穩(wěn)定性的要求下，以最經(jīng)濟(jì)的代價(jià)，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(jì)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