中国石油大学工程力学答案合集1演示教学.ppt

2020/6/12,Kylinsoft,Statics-Problems-1,静力学第1章作业/P23-1.1(l)*:,2020/6/12,Kylinsoft,Statics-Problems-2,静力学第1章作业/P23-1.1(g)*:,2020/6/12,Kylinsoft,Statics-Problems-3,静力学第1章作业/P24-1.2(k):,2020/6/12,Kylinsoft,Statics-Problems-4,静力学第1章作业/P27-1.3(c):,2020/6/12,Kylinsoft,Statics-Problems-5,静力学第1章作业/P27-1.3(e)*:,2020/6/12,Kylinsoft,Statics-Problems-6,静力学第2章作业/P58-2.3*:,Solution:,由此得到如下方程组：,解得：,2020/6/12,Kylinsoft,Statics-Problems-7,静力学第2章作业/P60-2.14*:,Solution:,按定义有:,So,expressions(a),(d),(e)arevalid.,2020/6/12,Kylinsoft,Statics-Problems-8,静力学第2章作业/P61-2.20:,Solution:,(a),Invectorform:,2020/6/12,Kylinsoft,Statics-Problems-9,(b),Invectorform:,2020/6/12,Kylinsoft,Statics-Problems-10,+,Solution:,静力学第2章作业/P63-2.28*:,2020/6/12,Kylinsoft,Statics-Problems-11,（a),Solution:,静力学第2章作业/P63-2.30*:,2020/6/12,Kylinsoft,Statics-Problems-12,(b),+,2020/6/12,Kylinsoft,Statics-Problems-13,O,OriginalforcesandcouplecanbereducedtoaforceandacoupleactingatpointO:,静力学第2章作业/P64-2.32:,Solution:,于是得到合力的大小、方向和作用线位置（如图所示）：,(或,或,),2020/6/12,Kylinsoft,Statics-Problems-14,+,Solution:,静力学第2章作业/P64-2.34*:,2020/6/12,Kylinsoft,Statics-Problems-15,静力学第3章作业/P85-3.2*:,Solution:,FromtheFBDofthebeaminFig:,+,2m,2020/6/12,Kylinsoft,Statics-Problems-16,静力学第3章作业/P86-3.11:,Solution:,Studyingpersonandladder,drawFBD,(a)x=1.5m,+,2020/6/12,Kylinsoft,Statics-Problems-17,(b),2020/6/12,Kylinsoft,Statics-Problems-18,静力学第3章作业/P87-3.18:,Solution:,0.5m,(1)Studyingentirestructure,FromtheFBDofentirestructureinFig:,+,(2)StudyingmemberAB,FromtheFBDofmemberABinFig:,0.5m,1.6m,+,2020/6/12,Kylinsoft,Statics-Problems-19,(3)StudyingmemberACE,FromtheFBDofmemberACEinFig:,0.8m,A,E,C,0.8m,0.6m,0.6m,+,2020/6/12,Kylinsoft,Statics-Problems-20,静力学第3章作业/P90-3.28(f)*:,Solution:,(1)StudyingmemberCD,FromtheFBDofmemberCDinFig:,显然，本题中在约束A、B、C、D处没有水平方向的作用力,M,C,3m,1m,+,+,2020/6/12,Kylinsoft,Statics-Problems-21,(2)StudyingmemberABC,A,C,1m,2m,1m,FromtheFBDofmemberCDinFig:,+,+,2020/6/12,Kylinsoft,Statics-Problems-22,静力学第3章作业/P91-3.40:,Solution:,(1)FromtheFBDofjointAinFig:,A,1,2,2020/6/12,Kylinsoft,Statics-Problems-23,(2)FromtheFBDofjointBinFig:,B,2020/6/12,Kylinsoft,Statics-Problems-24,(3)FromtheFBDofjointDinFig:,D,1,2,2020/6/12,Kylinsoft,Statics-Problems-25,(4)FromtheFBDofjointCinFig:,C,2020/6/12,Kylinsoft,Statics-Problems-26,静力学第3章作业/P92-3.43*:,Solution:,(1)FromtheFBDofjointDinFig:,D,(1)FromtheFBDofjointinFig:,H,2,3,2020/6/12,Kylinsoft,Statics-Problems-27,Solution:,+,+,+,静力学第4章作业/P111-4.2*:,2020/6/12,Kylinsoft,Statics-Problems-28,静力学第4章作业/P113-4.12*:,Solution:,FromtheFBDofbentpipeandcableinFig:,2020/6/12,Kylinsoft,Statics-Problems-29,无解！？,2020/6/12,Kylinsoft,Statics-Problems-30,Solution:,静力学第4章作业/P113-4.13*:,2020/6/12,Kylinsoft,Statics-Problems-31,静力学第4章作业/P114-4.14(b):,Solution:,S,令形心坐标为(xc,yc),按定义有:,2020/6/12,Kylinsoft,Statics-Problems-32,静力学第4章作业/P115-4.24:,Solution:,已知crucible的密度rc=2000kg/m3,外径R=0.28m,内径r=0.2m;iron的密度ri=7200kg/m3,O,Studyingcrucible，DrawingFBDinFig.,Gi,Gc,+,2020/6/12,Kylinsoft,Statics-Problems-33,2020/6/12,Kylinsoft,Statics-Problems-34,Solution:,x=0,静力学第4章作业/P116-4.27*:,2020/6/12,Kylinsoft,Statics-Problems-35,静力学第5章作业/P131-5.2:,解：,假设系统是静力平衡的,先研究圆柱，有,得,再研究方块，有,得,而,2020/6/12,Kylinsoft,Statics-Problems-36,Discussion:,1.方块会不会先翻倒?,2.如果圆柱和方块的接触面不光滑,会怎样?,x2,x2=?,2020/6/12,Kylinsoft,Statics-Problems-37,Solution:,总体分析:,分析木条:,圆盘分析:,解之得：,N,f,f,f,C,B,A,.,=22.06,=,=,达到最大静摩擦力时:,解之得：,静力学第5章作业/P132-5.10*:,2020/6/12,Kylinsoft,Statics-Problems-38,静力学第5章作业/P132-5.12:,解：,假设系统是静力平衡的,先研究桩子CBD，有,再研究杆AB，有,2020/6/12,Kylinsoft,Statics-Problems-39,只有当fAfAmax或fBfBmax时，杆AB才能移动，由以上计算结果可知，当P6300(N)，杆AB在A点处开始移动,2020/6/12,Kylinsoft,Statics-Problems-40,静力学第5章作业/P133-5.18*:,Solution:,因此:,2020/6/12,Kylinsoft,Statics-Problems-41,Solution:,木块翻转临界时：,滑动时：,静力学第5章作业/P133-5.19*:,2020/6/12,Kylinsoft,Statics-Problems-42,当P=600lb时：,当P=200lb时：,Solution:,静力学第5章作业/P134-5.22*:,2020/6/12,Kylinsoft,MOM-Problems-43,第六次作业/P34-1.1(b):,Solution,N1=P,N2=0,N3=P,2020/6/12,Kylinsoft,MOM-Problems-44,第六次作业/P34-1.6:,Solution,研究活塞杆，有,研究右挡盖，有,得,2020/6/12,Kylinsoft,MOM-Problems-45,第六次作业/P34-1.7*:,Solution,研究节点B，有,研究杆BC，有,研究杆AB，有,取,2020/6/12,Kylinsoft,MOM-Problems-46,第六次作业/P35-1.13*:,Solution,根据题意列出方程组：,解得,总伸长为,2020/6/12,Kylinsoft,MOM-Problems-47,第六次作业/P37-1.14*:,Solution,B,C,A,(1)AformulaforthedownwarddisplacementdCofpointC,P,P,(2)TheelongationdBoftheentirebar,2020/6/12,Kylinsoft,MOM-Problems-48,(3)Theratioroftheelongationoftheupperhalfofthebartotheelongationofthelowerhalfofthebar,Theelongationoftheupperhalfofthebar,Theelongationofthelowerhalfofthebar,So,2020/6/12,Kylinsoft,MOM-Problems-49,第六次作业/P37-1.21:,Solution,(1)静力平衡方程：,研究右挡板，有,(2)变形协调方程：,(3)求解方程组：,2020/6/12,Kylinsoft,MOM-Problems-50,P,第六次作业/P37-1.23*:,Solution,P,(1)Equationofequilibrium,(2)Equationofcompatibility,(3)Force-displacementrelations,得补充方程,2020/6/12,Kylinsoft,MOM-Problems-51,解得,有,2020/6/12,Kylinsoft,MOM-Problems-52,第六次作业/P37-1.24*:,Solution,变形过程中3根杆的长度始终满足下面的关系：,而3根杆的长度变化满足下面的关系：,(1)静力平衡方程：,研究节点A，有,(2)变形协调方程：,2020/6/12,Kylinsoft,MOM-Problems-53,(3)求解方程组：,2020/6/12,Kylinsoft,MOM-Problems-54,将A点的位移分量向各杆投影.得,变形关系为,(4)讨论：3根杆长度变化关系的另一种求法：,2020/6/12,Kylinsoft,MOM-Problems-55,RB,RA,第六次作业/P37-1.26:,Solution,A1,A2,(1)Equationofequilibrium,(2)Equationofcompatibility,RB,RB,(3)Force-displacementrelations,得补充方程,2020/6/12,Kylinsoft,MOM-Problems-56,解得,2020/6/12,Kylinsoft,MOM-Problems-57,材料力学第2章作业/P58-2.1(b):,Solution,2020/6/12,Kylinsoft,MOM-Problems-58,材料力学第2章作业/P59-2.11:,Solution,(1),对于AB段，,由强度条件得,由刚度条件得,2020/6/12,Kylinsoft,MOM-Problems-59,取,由强度条件得,由刚度条件得,对于BC段，,取,(2),取,(3),齿轮1安放在齿轮2、3中间。,2020/6/12,Kylinsoft,MOM-Problems-60,材料力学第2章作业/P59-2.14:,Solution,方法一（传统法）：,1.解除某些约束，施加相应约束反力，使之成为静定基；,2.扭矩与变形协调方程：,得TB=5T0/4,3.外扭矩3T0和T0作用处的转角分别为：,=,2020/6/12,Kylinsoft,MOM-Problems-61,材料力学第2章作业/P59-2.14:,Solution,方法二（船长法）：,1.解除约束，施加约束反力；,2.扭矩与变形协调方程：,右起第一段：TB右起第二段：TB-T0右起第二段：TB-4T0,得TB=5T0/4,3.可见，右起第一段和第二段的扭矩都大于0，最大转角发生在外扭矩3T0作用处：,2020/6/12,Kylinsoft,MOM-Problems-62,材料力学第3章作业/P72-3.1(c):,Solution,对于1-1截面，有,对于2-2截面，有,2020/6/12,Kylinsoft,MOM-Problems-63,补充：内力图,-,-,2020/6/12,Kylinsoft,MOM-Problems-64,Shear-ForceandBending-MomentEquations,材料力学第3章作业/P73-3.2(a):,Solution,2020/6/12,Kylinsoft,MOM-Problems-65,(2)Shear-ForceandBending-MomentDiagrams,-,(3)MaximumShearForcesandBendingMoments,2020/6/12,Kylinsoft,MOM-Problems-66,材料力学第3章作业/P73-3.3(b)*:,Solution,控制截面法？,2020/6/12,Kylinsoft,MOM-Problems-67,Solution,材料力学第4章作业/P90-4.6*:,1.求约束反力,2.求弯矩,作出弯矩图,3.求许用载荷,由强度条件得,2020/6/12,Kylinsoft,MOM-Problems-68,材料力学第4章作业/P91-4.8:,Solution,AT-beammadeofcastironinpurebending.Knowingtheratiooftensileallowablestresstocompressiveallowablestressisst/sc=1/4.Determinethereasonablewidthboftheflange.,2020/6/12,Kylinsoft,MOM-Problems-69,材料力学第4章作业/P91-4.13:,Solution,1.求剪力和弯矩,作出剪力图和弯矩图,2.根据胶合面强度条件求P,整个截面都是危险截面，考虑剪应力互等定理，有,2020/6/12,Kylinsoft,MOM-Problems-70,3.根据截面剪应力强度条件求P,整个截面都是危险截面，有,4.根据截面正应力强度条件求P,A截面是危险截面，有,5.综上所述，取,2020/6/12,Kylinsoft,MOM-Problems-71,材料力学第5章作业/P110-5.3(c)*:,Solution,1.求约束反力,2.求弯矩方程,2020/6/12,Kylinsoft,MOM-Problems-72,3.求挠曲线方程：,代入边界条件：,得：,最大挠度：,两端转角：,中间挠度：,取合理解,2020/6/12,Kylinsoft,MOM-Problems-73,材料力学第5章作业/P111-5.8:,Solution,ThecantileverbeamshowninthefigurehasmomentsofinertiaI1andI2inpartsACandCB,respectively.(a)Usingthemethodofsuperposition,determinethedeflectiondBatthefreeendduetotheloadP.(b)DeterminetheratiorofthedeflectiondBtothedeflectiond1atthefreeendoftheprismaticcantileverbeamwithmomentofinertiaI1carryingthesameload.,B,A,C,(a),B,C,A,2020/6/12,Kylinsoft,MOM-Problems-74,B,A,C,B,C,A,2020/6/12,Kylinsoft,MOM-Problems-75,B,A,C,(b),2020/6/12,Kylinsoft,MOM-Problems-76,B,A,C,Discussion,Useenergymethod,2020/6/12,Kylinsoft,MOM-Problems-77,材料力学第5章作业/P111-5.9:,Solution,1.解除某些约束，施加相应约束反力，使之成为静定基；,2.变形协调方程：,=,查表得,2020/6/12,Kylinsoft,MOM-Problems-78,3.求其它约束反力：,2020/6/12,Kylinsoft,MOM-Problems-79,材料力学第5章作业/P112-5.13*:,Solution,Thebars1and2havethesametensilerigidityEA.(1)IfthebeamABisconsideredasrigid,determinetheinternalforcesinthetwobars.(2)IfthebeamABisconsideredasdeformablewithbendingrigidityEI,determinetheinternalforcesinthetwobars.,(1)thebeamABisconsideredasrigid,P,P,(a)Equationofequilibrium,(b)Equationofcompatibility,2020/6/12,Kylinsoft,MOM-Problems-80,(1)thebeamABisconsideredasrigid,P,P,(a)Equationofequilibrium,(b)Equationofcompatibility,(c)Force-displacementrelations,得补充方程,解得,2020/6/12,Kylinsoft,MOM-Problems-81,(2)thebeamABisconsideredasdeformable,P,(a)Equationofequilibrium,(b)Equationofcompatibility,(c)Force-displacementrelations,得补充方程,解得,2020/6/12,Kylinsoft,MOM-Problems-82,1.危险点位于圆轴固定端横截面的最上处和最下处（A点和B点）,材料力学第6章作业/P135-6.1(d):,m,d,Solution:,忽略横力弯曲剪力的影响,2.用单元体表示危险点的应力状态,3.用应力圆表示危险点的应力状态,(,),(-,),(0,-),A,B,A点：,或,B点：,或,2020/6/12,Kylinsoft,MOM-Problems-83,材料力学第6章作业/P135-6.3(d):,40,20,40,如右图所示单元体，画出对应的应力圆,Solution,tmax,(-40,-40),(-20,40),1.主应力和主方向,s3,s1,11.23,71.23,2.如图所示在单元体上画出主平面方向,52.02,3.最大剪应力,2020/6/12,Kylinsoft,MOM-Problems-84,材料力学第6章作业/P135-6.4(b)*:,30,30,50,20,如右图所示单元体，画出对应的应力圆,Solution,s1,s2,tmax,(30,-20),(50,20),60,(52.32,-18.66),a=30,2020/6/12,Kylinsoft,MOM-Problems-85,材料力学第6章作业/P136-6.7*:,Solution,30,如右下图所示，在A点取单元体并进行应力状态分析,a=120,Atestofthinwalledtubeisshowninthefigure.IftheloadsareaconcentratedforceP=20kNandatorqueT=600Nm.Thediameterofthetubeisd=50mm,thicknessisd=2mm.(1)DeterminethenormalandshearstressesontheinclinedsectionatpointA.(2)DeterminethemagnitudeandorientationoftheprincipalstressesatpointA.(Drawstresselement.),2020/6/12,Kylinsoft,MOM-Problems-86,(2),(61.21,-70.63),(0,70.63),s3,s1,66.57,33.29,(1),2020/6/12,Kylinsoft,MOM-Problems-87,材料力学第6章作业/P136-6.11:,Solution,Whenatrainpassthroughasteelbridge,thestrainstestedbyinstrumentareex=0.0004,ey=-0.00012atpointA.FindthenormalstressesindirectionsxandyatpointA.(E=200GPa,m=0.3),2020/6/12,Kylinsoft,MOM-Problems-88,材料力学第6章作业/P137-6.17*:,Solution,薄壁上任意一点都是危险点，在薄壁上任一点A取单元体并进行应力状态分析,Athin-walledtubeshowninthefigureismadeofcastiron.KnowingitsoutsidediameterisD=200mm,thicknessofthewallist=15mm,theinnerpressureisp=4MPa,thecompressiveforceisP=200kN.Theallowabletensileandcompressivestressesofcastironarest=30MPaandsc=120MPa,respectively.Examthestrengthofthethin-walledtube.,2020/6/12,Kylinsoft,MOM-Problems-89,由上可知,由第一强度理论可知,强度满足,由第二强度理论可知,强度满足,由莫尔强度理论可知,强度满足,2020/6/12,Kylinsoft,MOM-Problems-90,材料力学第6章作业/P137-6.18:,Solution,1.求A点所在横截面的内力,2.在点A处取单元体并进行应力状态分析,AcantileverbeamofrectangularcrosssectionissubjectedtoaconcentratedloadP=120kN,actingatthefreeend.Thebeamhaswidthb=100mm,andheighth=20