习题与课堂练习画剪力弯矩图8-1ARBRABCq=10kN/mm.20m.40QM0BM0602040100602040.R...R..qAAkN.RA3310YkN.RB6721.332.670.27m.1300.36ARBRABm.20m.10C10N·mNRRBA50QM50N10N·m8-2ARBRAa2Caq0BM02212aRaaqaaqAqaRA43qaRB49QM0.28qa23/4qa5/4qa1qaa.7500.5qa28-38-4ARBRADCq2qama2aaQM5/6qa1qaa6111/2qa20AM052332a.aqqaaRBqaRB613qaRA657/6qa5/6qa21/6qa213/72qa2B例1绘制简支梁的内力图q=4kN/m1m1m2mABC2m1m1mM=16kN.mEFGPF=8kND示例(1)求支座反力)(17kNRAF)(7kNRGFF=17kNRA1m1mBACF=8kNP2m2m1mF=7kNRG1mq=4kN/mDHM=16kN.mEFG解:(2)作剪力图控制截面的剪力:kNQ17AFkNRQ9BFkNQ7EFABCF图(单位kN)Q11EF1G798A121BB1CF=17kNRA1m1mBACF=8kNP2m2mEFG1mF=7kNRG1mq=4kN/mDHM=16kN.mEFGABCDF图(单位kN)Q2.25m11EF1G798A121BB1CF=17kNRA1m1mBACF=8kNP1DH2m2mEFG1mF=7kNRG1mq=4kN/mDHM=16kN.mEFG(3)作弯矩图控制截面的弯矩:kN.m17BM0AMkN.m62CMkN.m03EM0GMkN.m3L2FMkN.mR7FMABCABCM图(单位kN.m)DHDF图(单位kN)Q2.25m7EFG11EF1G798A121BB1CF=17kNRA1m1mBACF=8kNP1DH2m2mEFG1mF=7kNRG1mq=4kN/mDHM=16kN.mEFG26173636.13023ABCDF图(单位kN)Q2.25m11EF1G798A121BB1CF=17kNRA1m1mBACF=8kNP1DH2m2mEFG1mF=7kNRG1mq=4kN/mDHM=16kN.mEFGB3C3A1726BCABCF2D3D3H33ED3636.1HDF图(单位kN)2.25mF30237EF7416G11EF1G798A121BB1CF=17kNRA1m1mBACF=8kNP1DH2m2mEFG1mF=7kNRG1mq=4kN/mDHM=16kN.mEFGQM图(单位kN.m)例2作简支梁的内力图q=20kN/m4mA2m2mF=40kNCDPB示例解:)(70kNFAR)(50RkNFB(1)求支座反力q=20kN/mF=70kNRA4mA2mF=50kN2mRBF=40kNCDPBkNFF70ARACQkNFF50BRDBQkNFF1042070CDQCAQ(2)作剪力图各控制截面的剪力值:QF图(单位kN)Ax7010501050ECDBC1ABCABCD1M图(单位kN.m)2DE1DDF图(单位kN)QxFE250F=70kNRABACF=40kNP2m2mRBF=50kNq=20kN/mD4m501010EF100120122.51001F606070(3)作弯矩图0ACMmkNMMCDCA.120mkNMMDBDC.1000BDM选A、C、D、B为控制截面,各截面弯矩值为:AC段有均布荷载作用,用叠加法作M图,竖标F1F2的值为:mkN.40420812q=20kN/mF=70kNRA4mA2mF=50kN2mRBF=40kNCDPBQF图(单位kN)Ax7010501050ECDB练习1作简支梁的内力图练习q=10kN/m2m2mACBq=10kN/m2mF=5kNRA2mACBF=15kNRB(1)支座反力(2)剪力图q=10kN/m2mF=5kNRA5ADF图(单位kN)QC2mAC15BBF=15kNRB(3)弯矩图1055EA10M图(单位kN.m)11.25CDBq=10kN/m2mF=5kNRA5ADF图(单位kN)QC2mAC15BBF=15kNRB8-5检查下列剪力弯矩图是否正确q2qamaaABCa2a2qam23qa2qaqa2qa22qa2qa23qa23qa2qaABqP=qaAa4aqaaaaqaqaqaqaqa2qa22qa2811qa2qa232qa