经典-材料力学结构力学弯矩图-课件.ppt

1、(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(1)P作用下的M图：qL2q作用下的M图：221qL223qLP与q作用下的M图：(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2P

2、PLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(2)P作用下的M图：qL2q作用下的M图：221qLP与q作用下的M图：221qL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(3)P作用下的M图：q作用下的M图：221qL24qL25.4 qLP与q作用下的M图：直线与曲线相切22qL1PPT课件(15)(14)(13)(

3、12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(15)(14)(13)(12)(11

4、)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(4)(5)(6)从右向左作M图：PLPL从右向左作M图：223qL225qL221qL281qL从右向左作M图：PLPL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2P

5、PLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqL

6、PLLPP=2qLLqLPL2PLPLLL/22M=qLqL(7)(8)(9)利用对称性作M图：221qL221qL281qL利用反对称性作M图：M21M21先计算支反力，再作M图：qL41241qL281qL2PPT课件(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(15)(14)(13)(12)(11)(10)(9)(8)(7)(6)(5)(4)

7、(3)(2)(1)一、梁L/2L/4L/4qLqLqL2M=qLP=qLLqLqLP=qLM=PL2PLLqLP=qLMLLqLLLL2PPLLLqLPLLPP=2qLLqLPL2PLPLLL/22M=qLqL(10)(11)(12)叠加法作M图：1.先考虑力偶作用PL2PL2.再叠加P的作用PL41先计算支反力，再作M图：P34P35PL34PL35先计算支反力，再作M图：kN4.1kN6.04.26.11.06.1(13)(14)(15)作M图,只需计算C截面弯矩Fl21作M图,只需计算C截面弯矩221qa曲线在B点与水平线相切281qa不用计算支反力，可快速作M图30303PPT课件(1

8、6)(17)(18)先计算支反力，再作M图：F31FaFa31直接作M图：2qa289qa直接作M图：601020(19)(20)(21)CD段直接作M图，AC段采用叠加法：2qa221qa相切力偶只影响BD段,直接用叠加法作M图：2qa2qa力偶只影响BC段,力只影响AC段,作M图：22qa2qa不与水平线相切4PPT课件aaaaaaam(22)从附属部分开始，直接作M图：mmmmqLL(22)(21)(20)(19)二、悬臂式刚架(18)(17)(16)PPLLL/2L/2L/2L/2030PLL2M=qaP=qaP=2qaqq4a2aaa2a2aa3aM=2qaqa2aa2m2m2m15

9、60q=102mM=PL(23)从附属部分开始，用“局部悬臂梁法”直接作M图：2481aq24qa相切28qa216qa215qa25.8 qa2381aq5PPT课件(24)(25)(26)22qL8qL222qLqL2482qL2qL8PL42qL2qL/8LqM=qL2L/2LLP2PLPLLqLP=2qLPLLPLqLLLP2PLLLLqLLMP=qLLqLL2PM=PLP=qLLqLqLP=qLM=qL2LqLqLqL/4L/4L/2一、梁(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)2PL9qL22PL34pL5pL3qL22

10、M2qL2qL22+pLpL22qL225qL3qL2222qLqL2882qL5qL2323225qL8qL2斜梁各截面弯矩值与所对应简支梁一样，作M图：所对应简支梁为：22qL8qL222qLqL2482qL2qL8PL42qL2qL/8LqM=qL2L/2LLP2PLPLLqLP=2qLPLLPLqLLLP2PLLLLqLLMP=qLLqLL2PM=PLP=qLLqLqLP=qLM=qL2LqLqLqL/4L/4L/2一、梁(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)2PL9qL22PL34pL5pL3qL22M2qL2qL22+

11、pLpL22qL225qL3qL2222qLqL2882qL5qL2323225qL8qL26PPT课件(27)(28)qL22(22)Lq2217qa215qa216qa8qa224qa2qa2PL2PL23qaqa222055530(21)(20)(19)二、悬臂式刚架(18)(16)PPLLL/2L/2L/2L/2030PLM=PLL2M=qaP=qaP=2qaqq4a2aaa2a2aa3aM=2qaq2m2m2m1560q=102mPLPL22PL23PL3PL3PL22PL9qa28a2aa228qa(17)用“局部悬臂梁法”直接作M图，P力通过截面以上部分还有力偶，所以弯矩不为0：

12、用“局部悬臂梁法”直接作M图，P力通过截面弯矩为07PPT课件(29)(30)qL22(22)Lq2217qa215qa216qa8qa224qa2qa2PL2PL23qaqa222055530(21)(20)(19)二、悬臂式刚架(18)(16)PPLLL/2L/2L/2L/2030PLM=PLL2M=qaP=qaP=2qaqq4a2aaa2a2aa3aM=2qaq2m2m2m1560q=102mPLPL22PL23PL3PL3PL22PL9qa28a2aa228qa(17)与杆件轴线相切用“局部悬臂梁法”直接作M图，P力通过截面弯矩为0用“局部悬臂梁法”直接作M图8PPT课件(31)(32

13、)用“局部悬臂梁法”直接作M图：Pl21注：P力通过点弯矩为0Pl21Pl21PlPl2Pl2Pl注：P力通过点弯矩为0用“局部悬臂梁法”直接作M图：9PPT课件(33)(34)(28)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaaPL2LLLLP2LLLPPaaa2PLqa2PaPaPa2AB注：AB段弯矩为常数。(28)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaaPL2LLLLP2LLLPPaaa2PLqa2PLPLPL3用“局部悬臂梁法”直接作M图：用“局部悬臂梁法”直接作M图：10PPT课件(35)(36)(28

14、)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaaPL2LLLLP2LLLPPaaa2PLqa2PL2PLPL3(28)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaaPL2LLLLP2LLLPPaaa2PLqa22qa221qa281qa11PPT课件(37)(38)(28)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaaPL2LLLLP2LLLPPaaa2PLqa22qa2qa221qa与杆件轴线相切(28)(27)(26)(25)(24)(23)qq2aaaa/2qqaa/2aqqaaa

15、PL2LLLLP2LLLPPaaa2PLqa2221qa221qa2qa12PPT课件2m2m2m(34)(33)(32)(31)(30)(29)qqaaaaaLqLL/2L/2qL3m30kN20kN/m3m3m3m40kN10kN/mP=40kN2m2m2maPaa8010060100(39)(40)22qaqa222qa2cos2qL2+2qL22cosqL2qL2222qL90901008060100100PaPa2m2m2m(34)(33)(32)(31)(30)(29)qqaaaaaLqLL/2L/2qL3m30kN20kN/m3m3m3m40kN10kN/mP=40kN2m2m2

16、maPaa13PPT课件(41)(42)22qaqa222qa2cos2qL2+2qL22cosqL2qL2222qL90901008060100100PaPa2m2m2m(34)(33)(32)(31)(30)(29)qqaaaaaLqLL/2L/2qL3m30kN20kN/m3m3m3m40kN10kN/mP=40kN2m2m2maPaa331514PPT课件(43)(44)415qa221qa2822qa22qaqa2qa22qa2qa2PLPLPa22Pa2PaPa(40)(39)(38)(37)L(36)(35)三、简支式刚架aaqq2aqa2a2qaa2qaqaaqq/2a/2qa

17、aaa/2PLPPaaa/2a2Pa2Paqa227qa415PPT课件(45)(46)(47)支座B无反力，AB段无变形2m2m2m(34)(33)(32)(31)(30)(29)qqaaaaaLqLL/2L/2qL3m30kN20kN/m3m3m3m40kN10kN/mP=40kN2m2m2maPaaBAPaPa180180不用计算支反力，直接作M图AB计算A支座水平反力，即可作M图155.228451516PPT课件(48)(49)415qa221qa2822qa22qaqa2qa22qa2qa2PLPLPa22Pa2PaPa(40)(39)(38)(37)L(36)(35)三、简支式刚

18、架aaqq2aqa2a2qaa2qaqaaqq/2a/2qaaaa/2PLPPaaa/2a2Pa2Paqa227qa4计算A支座水平反力，即可作M图ABABA、B支座无水平反力，直接作M图17PPT课件(51)(50)415qa221qa2822qa22qaqa2qa22qa2qa2PLPLPa22Pa2PaPa(40)(39)(38)(37)L(36)(35)三、简支式刚架aaqq2aqa2a2qaa2qaqaaqq/2a/2qaaaa/2PLPPaaa/2a2Pa2Paqa227qa4无水平支反力，直接作M图无水平支反力，直接作M图18PPT课件(52)(53)(46)2.595q7qL2

19、4qL24223qL345453904806906904Pa334Pa4Pa2qa225qaqa22qa22qa22(45)(44)(43)(42)(41)3m4m4mqqLqLLL40kN10kN/m3m3m3m3m3m4Paaaa2aqaqaa2a2M=qaqa/2a/2a3qa22先计算A支座水平支反力，再作M图ABAB先计算B支座水平支反力，再作M图19PPT课件(54)(55)(46)2.595q7qL24qL24223qL345453904806906904Pa334Pa4Pa2qa225qaqa22qa22qa22(45)(44)(43)(42)(41)3m4m4mqqLqLLL

20、40kN10kN/m3m3m3m3m3m4Paaaa2aqaqaa2a2M=qaqa/2a/2a3qa22先计算支反力，再作M图先计算支反力，再作M图20PPT课件(57)(56)(46)2.595q7qL24qL24223qL345453904806906904Pa334Pa4Pa2qa225qaqa22qa22qa22(45)(44)(43)(42)(41)3m4m4mqqLqLLL40kN10kN/m3m3m3m3m3m4Paaaa2aqaqaa2a2M=qaqa/2a/2a3qa22先计算支反力，再作M图先计算支反力，再作M图21PPT课件MM2Pa2PP2无弯矩N=P/222qL2q

21、L2PLPL2qLqL22(52)(53)(50)(51)(48)(47)aaaaMaa2aPPLLL1.5LLLLqLPPL2LLqLLMPa2先计算支反力，再作M图无支反力，直接作M图(58)(59)22PPT课件(60)(61)MM2Pa2PP2无弯矩N=P/222qL2qL2PLPL2qLqL22(52)(53)(50)(51)(48)(47)aaaaMaa2aPPLLL1.5LLLLqLPPL2LLqLLMPa2AA处无支反力，直接作M图利用反对称性，直接作M图10510510510523PPT课件(62)(63)先计算A或B处支反力，再作M图AB、CD段没有弯曲变形，直接作M图MM

22、2Pa2PP2无弯矩N=P/222qL2qL2PLPL2qLqL22(52)(53)(50)(51)(48)(47)aaaaMaa2aPPLLL1.5LLLLqLPPL2LLqLLMPa2ABABCD24PPT课件APLMM/2M/2M/225kN.m25kN.mPa/25qa/29qa/2(58)(57)(56)(55)(54)LL/2L/2PL/2L/2LML/2q=20kN/m50kN50kN0.5m0.5m2m4m4ma/2a/2Pa/2a/2a3a3a2aqqa2qaPa/265kN.m25kN.m25kN.mPLPLPL四、三铰式刚架AAB以B为矩心，计算A处水平支反力，再作M图计

23、算A处支反力为0，直接作M图(64)(65)25PPT课件(66)(67)MM2Pa2PP2无弯矩N=P/222qL2qL2PLPL2qLqL22(52)(53)(50)(51)(48)(47)aaaaMaa2aPPLLL1.5LLLLqLPPL2LLqLLMPa2PLMM/2M/2M/225kN.m25kN.mPa/25qa/29qa/2(58)(57)(56)(55)(54)LL/2L/2PL/2L/2LML/2q=20kN/m50kN50kN0.5m0.5m2m4m4ma/2a/2Pa/2a/2a3a3a2aqqa2qaPa/265kN.m25kN.m25kN.mPLPLPL四、三铰式刚

24、架B、A处无水平支反力，直接作M图AABB、A处无水平支反力，AC、DB无弯曲变形，EC、ED也无弯曲变形ABCDE26PPT课件A图。支座水平反力，即可作计算出段弯矩为常数。点为直线，弯矩图过向相反；支座反力大小相等，方、特点：MADECBA图。即可作支座水平反力，或。计算出处弯矩为图对称，荷载，特点：对称结构，对称MBACM0PLMM/2M/2M/225kN.m25kN.mPa/25qa/29qa/2(58)(57)(56)(55)(54)LL/2L/2PL/2L/2LML/2q=20kN/m50kN50kN0.5m0.5m2m4m4ma/2a/2Pa/2a/2a3a3a2aqqa2qaP

25、a/265kN.m25kN.m25kN.mPLPLPL四、三铰式刚架(68)(69)ABCDEABCPL41PL4127PPT课件A图。支座水平反力，即可作计算出形。为二力折杆，有弯曲变形；为二力杆，没有弯曲变特点：MBCBAC22qa/32qa2qa/2PL(65)(64)(63)(62)(61)(60)(59)qaaaaq1.5aaaM1.5aaaq1.5aaaaa1.5aq2aaaPLLqa/22qa/222qa/2MMMMqa2qa2/8MMMM/82qaqa2/82qa/322qa/3222qa/3qa/22PL2MMMqa(70)(71)ABABC图。即可作支座水平反力，或。计算出

26、处弯矩为图对称，荷载，特点：对称结构，对称MBACM0C28PPT课件A22qa/32qa2qa/2PL(65)(64)(63)(62)(61)(60)(59)qaaaaq1.5aaaM1.5aaaq1.5aaaaa1.5aq2aaaPLLqa/22qa/222qa/2MMMMqa2qa2/8MMMM/82qaqa2/82qa/322qa/3222qa/3qa/22PL2MMMqa(72)(73)ABCABC图。即可直接作。处弯矩为。也反对称，称荷载，反力特点：对称结构，反对MCXXBA00图。即可直接作处弯矩为。，列平衡方程计算得力很重要，特点：计算支座水平反MCXXAB00029PPT课件

27、图。，即可直接作弯矩为、。弯矩图对称。也对称，荷载，反力特点：对称结构，对称MBAYC00图。，即可直接作弯矩为处、弯矩图对称。荷载，特点：对称结构，对称MCBA022qa/32qa2qa/2PL(65)(64)(63)(62)(61)(60)(59)qaaaaq1.5aaaM1.5aaaq1.5aaaaa1.5aq2aaaPLLqa/22qa/222qa/2MMMMqa2qa2/8MMMM/82qaqa2/82qa/322qa/3222qa/3qa/22PL2MMMqaABCABC(74)(75)30PPT课件22qa/32qa2qa/2PL(65)(64)(63)(62)(61)(60)(

28、59)qaaaaq1.5aaaM1.5aaaq1.5aaaaa1.5aq2aaaPLLqa/22qa/222qa/2MMMMqa2qa2/8MMMM/82qaqa2/82qa/322qa/3222qa/3qa/22PL2MMMqa(76)ABC图。，即可直接作弯矩为，计算出方程，为矩心，列写力矩平衡。以征得为二力折杆，由几何特特点：MCXAXYCBBBB031PPT课件(77)(78)M/43M/4M/2M/2M/2M/236kN.m36kN.m2q2q对称23qa/82qa/82qa/2100kN.m200kN.m300kN.m300kN.m3m1.5m1.5m(71)(70)(69)(68

29、)(67)(66)aaaaL/2L/2L/2L/23m2m3m12kN2mq2q2m2m2m2mqa/2a/2a2aa1.5m5m3m60kN100kN.mqa/22qa/823qa/82M/2M/2M/2qq2q2qABCABC图。即可直接作的水平反力，或，计算出弯矩为、。弯矩图对称。也对称，荷载，反力特点：对称结构，对称MBABAYC00图。即可直接作的水平反力，或计算出，弯矩为、特点：MBACBA083003100310032PPT课件A(80)(79)M/43M/4M/2M/2M/2M/236kN.m36kN.m2q2q对称23qa/82qa/82qa/2100kN.m200kN.m3

30、00kN.m300kN.m3m1.5m1.5m(71)(70)(69)(68)(67)(66)aaaaL/2L/2L/2L/23m2m3m12kN2mq2q2m2m2m2mqa/2a/2a2aa1.5m5m3m60kN100kN.mqa/22qa/823qa/82M/2M/2M/2qq2q2qABCABC图。即可直接作的水平反力，、计算出，弯矩为、特点：MBACBA0图。即可直接作的水平反力，、计算出，弯矩为、特点：MBACBA033PPT课件图。即可直接作，弯矩为、，计算出方程，为矩心，列写力矩平衡。以征得为二力折杆，由几何特特点：MCBAXAXYCBBBB0(82)(81)M/43M/4M

31、/2M/2M/2M/236kN.m36kN.m2q2q对称23qa/82qa/82qa/2100kN.m200kN.m300kN.m300kN.m3m1.5m1.5m(71)(70)(69)(68)(67)(66)aaaaL/2L/2L/2L/23m2m3m12kN2mq2q2m2m2m2mqa/2a/2a2aa1.5m5m3m60kN100kN.mqa/22qa/823qa/82M/2M/2M/2qq2q2qABCABCM图。即可直接作，弯矩为、，计算出方程，为矩心，列写力矩平衡。以征得为二力折杆，由几何特特点：MCBAXAXYCBBBB0234PPT课件(84)(83)2qa22qa2qa

32、2qL/2PaPa/4Pa/4(77)(76)(75)(74)(73)(72)五、复杂刚架qa2a2aqa/2aaaqL/2L/2L/2qLLLLaaaPaPPa/2a/2aaPaPaqL/822qL/322qa/8qa/222qaqa2ABCDEABCDEE图。即可直接作段没有弯曲变形，、形，为二力杆，没有弯曲变。弯矩图对称。也对称，荷载，反力特点：对称结构，对称MCEDCABYC0图。即可直接作水平反力，内力、支座计算出段没有弯曲变形。形，为二力杆，没有弯曲变特点：MDABBEAB35PPT课件图。即可直接作为斜梁。没有弯曲变形，为二力杆，、特点：MACBCABE2qa22qa2qa2qL

33、/2PaPa/4Pa/4(77)(76)(75)(74)(73)(72)五、复杂刚架qa2a2aqa/2aaaqL/2L/2L/2qLLLLaaaPaPPa/2a/2aaPaPaqL/822qL/322qa/8qa/222qaqa2(85)(86)ABCABC图。即可直接作杆如同简支梁。，处弯矩为、特点：MACCBA036PPT课件2qa22qa2qa2qL/2PaPa/4Pa/4(77)(76)(75)(74)(73)(72)五、复杂刚架qa2a2aqa/2aaaqL/2L/2L/2qLLLLaaaPaPPa/2a/2aaPaPaqL/822qL/322qa/8qa/222qaqa2E(87

34、)(88)ABCDEABCD。处弯矩为、为二力杆，为悬臂刚架，基本部分为外伸梁，附属部分，特点：0CAACCDEAB相切，弯矩图在处弯矩为、。为悬臂刚架，基本部分为简支梁，附属部分，特点：BBABCDAB037PPT课件E三处反力是必须的。、。计算处弯矩为、为悬臂刚架，基本部分为二力杆，附属部分，、特点：DBABAABDBCAC0,2qa/82qaPa/2Pa/2Pa/2Pa/2PaaaaaPaaaaqqaa2a2aaqaqaaaaaP2kNq=10kN/m2m2m2m2m4m4m(78)(79)(80)(81)(82)Pa/2Pa/2对称qa222qa2qa/23qa24Pa6Pa4P-8P

35、a12kN.m4kN.m8kN.m80kN.m24kN.m56kN.m(89)(90)2qa/82qaPa/2Pa/2Pa/2Pa/2PaaaaaPaaaaqqaa2a2aaqaqaaaaaP2kNq=10kN/m2m2m2m2m4m4m(78)(79)(80)(81)(82)Pa/2Pa/2对称qa222qa2qa/23qa24Pa6Pa4P-8Pa12kN.m4kN.m8kN.m80kN.m24kN.m56kN.mABCDABCDE四处反力是必须的。、。计算处弯矩为、为基本部分为附属部分，特点：ECBAECBAABCDBE0,38PPT课件。处弯矩为、悬臂梁为基本部分为二力杆，梁，杆为附属

36、部分，为简支特点：0,CBACDBCAB2qa/82qaPa/2Pa/2Pa/2Pa/2PaaaaaPaaaaqqaa2a2aaqaqaaaaaP2kNq=10kN/m2m2m2m2m4m4m(78)(79)(80)(81)(82)Pa/2Pa/2对称qa222qa2qa/23qa24Pa6Pa4P-8Pa12kN.m4kN.m8kN.m80kN.m24kN.m56kN.m(92)(91)ABCDABCDEF。处弯矩为、荷载的简支梁，为中间有集中。再计算先计算，为二力杆，容易判断、特点：0,0FBAFBXXYCDEFABB39PPT课件可直接作弯矩图。处弯矩为为外伸梁，为外伸斜梁，为二力杆，特

37、点：0CCBACAB为矩心列方程。以和分别取水平反力即可。、的简支梁，计算布荷载为中间受集中荷载和分支梁，为中间受集中荷载的简图。为简支梁，直接作弯矩为二力杆，、特点：C,CEFBADBABEADCFCEDEPa4PaPa2Pa2qa2qa/22qa/4220kN.m8kN.m(86)(85)(83)2m2m2aaaaaa2aPqa/2aqaaa/210kN1mq=4kN/m1m2m2m21.82kN.m21.82kN.m(84)5kN5kN5kN4X3m=12m3m8m-3.536kN2.27kN2.27kN-5kN-10kN10.61kN2.27kN2.27kN-5kN10.61kN-3.

38、536kN-10kNPa4PaPa2Pa2qa2qa/22qa/4220kN.m8kN.m(86)(85)(83)2m2m2aaaaaa2aPqa/2aqaaa/210kN1mq=4kN/m1m2m2m21.82kN.m21.82kN.m(84)5kN5kN5kN4X3m=12m3m8m-3.536kN2.27kN2.27kN-5kN-10kN10.61kN2.27kN2.27kN-5kN10.61kN-3.536kN-10kN(94)(93)ABCABCDEF40PPT课件Pa4PaPa2Pa2qa2qa/22qa/4220kN.m8kN.m(86)(85)(83)2m2m2aaaaaa2a

39、Pqa/2aqaaa/210kN1mq=4kN/m1m2m2m21.82kN.m21.82kN.m(84)5kN5kN5kN4X3m=12m3m8m-3.536kN2.27kN2.27kN-5kN-10kN10.61kN2.27kN2.27kN-5kN10.61kN-3.536kN-10kN(95)ABCDE部分弯矩图。可进一步作，点。容易判断一直到点开始直接作弯矩图，附属部分，从为基本部分，其它都为特点：ABPYPXBEABBB,41PPT课件P/2PPP/280kN.mP3P80kN.m100kN.m60kN.m30kN.m70kN.m10kN.m40kN.m30kN.m2m2m2m2m2

40、m2m2m2m2m2m(90)(89)(88)(87)P2m2m2m2m1.5m20kN/m40kN2m2m4m4m22PP2m4m4m2m10kN/mm40kN20kN20kN10kN/m10kN/m10kN/m20kN.m20kN.m40kN.m80kN.m80kN.m2P(96)ABCDEFG力都是必不可少的。算各处支反部分开始作弯矩图，计部分，从处集中力作用在复杂刚架。以此增加二元体，完成三铰刚架为基本部分，特点：FGDEFFABC90kNm50kNm70kNm110kNm42PPT课件(97)(98)P/2PPP/280kN.mP3P80kN.m100kN.m60kN.m30kN.m

41、70kN.m10kN.m40kN.m30kN.m2m2m2m2m2m2m2m2m2m2m(90)(89)(88)(87)P2m2m2m2m1.5m20kN/m40kN2m2m4m4m22PP2m4m4m2m10kN/mm40kN20kN20kN10kN/m10kN/m10kN/m20kN.m20kN.m40kN.m80kN.m80kN.m2PABCDE弯矩图。考虑为简支梁，直接作点。到出发作弯矩图，可一直从然简支梁为附属部分，显三铰刚架为基本部分，特点：DEACXBCABDEB0ABCDE即可。再计算出、可计算出为矩心部分，以考虑容易判断为二力杆，、为基本部分，特点：BEEEEXXYCCDEX

42、YDECDAB,2243PPT课件图可顺利作出。变形，。只有中间矩形有弯曲处弯矩为、处只有水平反力，去掉不影响计算，也为二元体，、为二元体，、处反力都为、特点：容易判断MKHKIEEFCGCDBA0,0图。，即可作和可计算出为矩心，列写方程。杆，以考虑为矩心，列写方程；杆，以考虑为二力杆、特点：MYXHBCGABEFDEBB,(99)(100)P/2PPP/280kN.mP3P80kN.m100kN.m60kN.m30kN.m70kN.m10kN.m40kN.m30kN.m2m2m2m2m2m2m2m2m2m2m(90)(89)(88)(87)P2m2m2m2m1.5m20kN/m40kN2m

43、2m4m4m22PP2m4m4m2m10kN/mm40kN20kN20kN10kN/m10kN/m10kN/m20kN.m20kN.m40kN.m80kN.m80kN.m2PMPa/2Pa/2Pa/2Pa/2Pa/2Pa/24P4PPL/22qL/223qL/2(95)(94)(93)(92)(91)aaaaaaaaPaaaaaP2m4m4m2m4m030030PPL/2L/2LLqLLLMMM4P4P4P4P4PPL/2MABCDEFGHIJKABCDEFGH44PPT课件P21P21P21P21Pa21Pa21P21P21P21P21P21P21无弯曲变形部分无需计算反力。即段当然也无弯曲

44、变形。杆无弯曲变形弯矩图对称，容易判断逐段绘制弯矩图。结构法，力，再按照局部悬臂梁特点：应先计算支座反ABCDECE,ADBC,ABABCDE45PPT课件5.75.711301130kNm11240kNm1124055101061.1061.1054.354.3228.0228.0228.0228.0弯矩、轴力对称。桁架部分得解。处对桁架作用了，由此以及处反力，杆，计算梁式杆弯矩图。考虑绘制支座反力先计算三铰，看成三铰结构，特点：由EDAEAEAABCABCDE46PPT课件qL23qL23qL25qL25qL25qL212qL212qL230qL225。各杆轴力顺利计算出来反力后、，计算出

45、杆轴力为容易判断弯矩图和杆内力，就可作特点：先计算FC0FDDECBABABCDEF47PPT课件2qL212qL21ABCD0DABDCBAC内力为杆部分为二元体，特点：48PPT课件P4ABCD征直接作弯矩图可由刚架弯矩图基本特处都没有水平反力、特点：DCBA49PPT课件P21P21P21P21曲变形。忽略轴向变形时，无弯，弯矩图反对称。结构对称，荷载反对称Pa21的。第二层、第三层是一样后，做完第一层刚架弯矩图Pa21Pa2150PPT课件有弯曲变形。忽略轴向变形时，只有ABCPABCPa251PPT课件于计算支座反力。为二力杆，此题关键在、BCABABCDE52PPT课件BCBYCY

46、CX,0X 0XC,0MC0604Y1210620BkN20YB杆弯矩图可顺利作出）（DEBDBYBCNDYDX,0MD04N2Y420BCBkNNBC10,0Y 0YD,0X kNXD10kN20kN10kNm60402020206053PPT课件弯矩图可直接作出就不用计算支座反力，如果只做弯矩图的话，1005554PPT课件P2P4PP3P6P2P4图可直接作出先计算支座反力，弯矩PLPL2PL4PL3P2P4P655PPT课件计算支座反力是关键ABCDEGFAYBYCY,0MA0Ma4Ya3YCB,0Y 0YYYACBAED考虑ADEAYDGNEXEY,0ME0aYa5.0NADGGFB

47、C考虑BCGFBYCYDGN,0MF0a5.0Na2YaYDGCB解得：aM2YCaM3YBaMYAaM2NGDMMM2MMM56PPT课件计算支座反力是关键kN5.4YB kN5.10YA kN12MD(112)57PPT课件ABCD步骤为计算支座反力是关键，kN10YCDC：考虑ABCD30kNm弯矩图单位：30 kN20Y,0MAB考虑整体：1057530(113)58PPT课件步骤为计算支座反力是关键，qa21Y,0MABAD：考虑0aXa2XaY,0MCFAB 考虑整体：0XX,0XCF qa21XC qa21XF2qa212qa212qa2qa81(114)59PPT课件H步骤为计

48、算支座反力是关键，kN18Y,0MCBBC：考虑013181426610M,0MAA 考虑整体：kN10X,0XA 顺时针kNm6MA kN6Y,0YA 压：考虑结点kN10NCCH 拉kN8NCD 是零杆、FHDH(115)60PPT课件H步骤为计算支座反力是关键，kN18Y,0MCBBC：考虑013181426610M,0MAA 考虑整体：kN10X,0XA 顺时针kNm6MA kN6Y,0YA 压：考虑结点kN10NCCH 拉kN8NCD 6361824612是零杆、FHDHkNm弯矩图单位：61PPT课件步骤为计算支座反力是关键，逆时针：考虑kNm60M,kN30N,kN230NGHH

49、HDG kN18NC考虑整体：kN34NA(116)62PPT课件步骤为计算支座反力是关键，逆时针压：考虑kNm60M,kN30N,kN230NGHHHDG kN18NC考虑整体：607260 kN34NA446kNm弯矩图单位：63PPT课件步骤为计算支座反力是关键，：、分别考虑EGCE(117)64PPT课件步骤为计算支座反力是关键，：、分别考虑EGCEHEXEYEXEYkN1YE 65PPT课件步骤为计算支座反力是关键，：、分别考虑EGCEkN1YE 2211kNm弯矩图单位：66PPT课件杆的内力，步骤为、关键是计算CDGH,0MA 考虑整体：kN16NBD,0NDF 考虑下图可知DF

50、NCDNGHN 压kN16NCD ,0MF 拉kN22NGH 328896kNm弯矩图单位：(118)67PPT课件杆的内力，步骤为关键是计算CDABCDEF,0X 考虑整体：AXBX020XXBA ACEBDFAXCDNEFN,0MAEE ：考虑02N6XCDA BXCDNEFN,0MBFF ：考虑02N2204XCDB （拉）kN60NCD(119)68PPT课件ABCDEF杆的内力，步骤为关键是计算CD,0X 考虑整体：020XXBA ,0MAEE ：考虑02N6XCDA ,0MBFF ：考虑02N2204XCDB （拉）kN60NCD 8080kNm弯矩图单位：69PPT课件m2m2m