40弯曲内力1.长l的梁用绳向上吊起，如图所示。钢绳绑扎处离梁端部的距离为x。梁内由自重引起的最大弯矩|M|max为最小时的x值为：(A)/2l；(B)/6l；(C)(21)/2l；(D)(21)/2l。2.多跨静定梁的两种受载情况如图(a)、(b)所示。下列结论中哪个是正确的？(A)两者的剪力图相同，弯矩图也相同；(B)两者的剪力图相同，弯矩图不同；(C)两者的剪力图不同，弯矩图相同；(D)两者的剪力图不同，弯矩图也不同。3.图示(a)、(b)两根梁，它们的(A)剪力图、弯矩图都相同；(B)剪力图相同，弯矩图不同；(C)剪力图不同，弯矩图相同；(D)剪力图、弯矩图都不同。4.图示梁，当力偶Me的位置改变时，有下列结论：(A)剪力图、弯矩图都改变；(B)剪力图不变，只弯矩图改变；(C)弯矩图不变，只剪力图改变；(D)剪力图、弯矩图都不变。5.图示梁C截面弯矩MC=；为使MC=0，则Me=；为使全梁不出现正弯矩，则Me≥。6.图示梁，已知F、l、a。使梁的最大弯矩为最小时，梁端重量P=。xxllaMe(a)laMe(b)qqa2a(a)qqa2(b)aaaaaFMeaqaaqMel/2BCAl/2al/2al/2PFP417.图示梁受分布力偶作用，其值沿轴线按线性规律分布，则B端支反力为，弯矩图为次曲线，|M|max发生在处。8.图示梁，m(x)为沿梁长每单位长度上的力偶矩值，m(x)、q(x)、FS(x)和M(x)之间的微分关系为：Sd();dFxxd()dMxx。9.外伸梁受载如图，欲使AB中点的弯矩等于零时，需在B端加多大的集中力偶矩（将大小和方向标在图上）。10.简支梁受载如图，欲使A截面弯矩等于零时，则e21e/MM。1-10题答案：1.C2.D3.B4.B5.28e2Mql；42ql；22ql6.alaF247.m0/2；二；l/28.q(x)；FS(x)+m(x)9.10.1/211-60题.作图示梁的剪力图和弯矩图。解：xm=xlABxm0xlm0xdxq(x)m(x)xaaqCABaaqABqa/22Cl/3le1Me2MAq2aqa2qaaaFSxqa/22x3qa/222qa2qa2qa2Mqa2qaq2aqa2qaaaFSxx3qa/222qa2qa2qa2Mqaqaqa242解：解：解：qqa2aaqaqFSxqa/22x5qa/222qa2qa2Mqaqa2qqa2qaaxxFSMqa/22qa/22qa/22qa/42qaqaq2qa3qa22aaxxFSM2qaqa2qa22qa2q2qaqa2aaaxxFSMqaqa/22qaqa/22qa/22qa/22q2aqaqaxxFSMqaqaqa/22qa/22a2aqa2aqqxxFSMqa2qa/22qa/223qa/222qaqa43解：解：解：qa/2a/2xFSxMqa/4qa/2423qa/47qa/242aqa2aqqaxxFSMqa2qa/223qa/22qaqa2qa2aqaqFSMxxqa/62qa/27qa/242qa/2qa/622a2a2q2qa2qFSM3qa4qa2x2qa29qa/42xqa3qa2m2m20kN/mmkN2020kN/mmkN20F/kNSM/mkN2020xx201020203020a4aa2qa4qa2qFSM3qa27qa/22xxqa3qa3qa2qa23qa44解：解：解：aaaqa2qFSM5qa/6qa/6213qa/722xxqa/6qa/625qa/62a0qFSa/Mqa/60qa/30qa/20393xxa/2a/20q0qFSMxxqa/60qa/120qa/60a/12a/1220aq363=0.01620aq0q0qaqa/30aFSMxxqa/60a/3qa/60qa/30qa/309320aq9320aq2m4m8kNmkN162m2kN/m2kN/m4kN/mF/kNSM/mkN4xx128844440qa/2a/2FSMxxqa/40qa/40qa/120245解：解：解：0q0qaaFSMxxqa/20qa/20qa2/602aaaq2qaqaFSMxx9qa/82qa23qa/2qa/2qa/23qa/23qa/22aqaFSMxx7qa/125qa/12211qa/12qa/12121qa/2882aaaqqaqa/22FSMxxqaqa/22qa/2qa/2qa/222aaqqFSMxxqa/2225qa/3225qa/43qa/4qaaaaqaqqa2FSMxxqaqa/223qa/42qa/43qa/4qa/4246解：解：解：2m10kNmkN1m1m1m2kN2kN/m4xxF/kNSM/mkN28477372aaaqqaqa2FSMxxqaqa/423qa/42qa/4qa25qa/4aaaqqqa2FSMxxqaqa/22qa/2qa2qa/82aaaqqqaqa2FSMxxqaqa/223qa/22qa/2qa/23qa/2qa/822m2kN/mmkN2m2m2kN4xxF/kNSM/mkN262144aaaqaaqqa2qa/22FSMqaxxqaqa/45qa/42qa2qa/4247解：解：解：aaaqqqaqa2FSMxxqaqa/223qa/22qa/2qa/22qa3qa/2213qa/823m40kN3m2m50kN/m50kN/mxxF/kNSM/mkN4061.713.388.31.74m46.380a2aaq2qa2qa2FSxMxqa2qa23qa2qa2qa2a2a2aqqa2FSxMxqa/25qa/2qa22qa22qaaaaqqaqa2qaFSMqaqa/22xxqa/2qa2aaaqqqa2FSqaqa/22qa2Mqaxxqa/2248解：aa2aqaqqa2FSqa/82qa2Mxx3qa/2qa/23qa/22qa2qa/222m80kNmkN4m8m2m10kN/m64xF/kNSM/mkNx5822408016080104.2645.8maaaaqqa2FS13qa/722Mqa/65a/6xx5qa/65qa/62qa/62qa/62qa/62a2aqqaqa2FSMxxqa22qa2qa2qaaa/20qFSa/qa/42Mxxqa/60qa/307qa/1200qa/20393mF2m1m1mFS100NmN100Mxx49a/2a/2a/20q0qFSMxxqa/60qa/120qa/60a/12a/1220aq363=0.01620aq20aq/12aaaqqa/22FS5qa/42Mxx7qa/4qa/425qa/45a/43qa/429qa/322a...
