M.=9.55=0.35kNm,T=0.35kNm F1==4.12kN,Fn1=1.5kM,F2=1094kN,F2=3.98KN F=2.17KN,F=3.3lkN,M1=7595Nm,M2=258.7Nm FA=1.07KN,FB==789N,My1=3745Nm,M2=512.5Nm Mm=√51252+25872=57409Nm M=√M2+72=672.38Nm 2M d≥ 32×672.38×103 35.7mm v t[] 3.14×150 第19次作业 8-21 F50×103 =663MPa<[] A,3.14×20×12 F.4×50×10 =102MPa<[n A丌×(322-202) 8-25 F Fs=.=20kN, t, F4×20×103 As Tx222=526MPa <[Gl F_20×10 F2=20kNOb-A,22×10 90.9MPa<[o,] FM1_80×10 A110×(80-22) =1379MPa<[a 60×10 =1667MPa<[a] A210×(80-44)F k N F k N M N m M N m F k N F k N M N m M N m k N F k N F k N F k N r M F k N m T k N m n P M A z B z y y A y B y z z r t r e t e 1.07 , 7.89 , 37.45 . , 512.5 . 2.17 , 3.31 , 75.95 . , 258.7 . 4.12 , 1.5 ; 10.94 , 3.98 9.55 0.35 . , 0.35 . 1 2 1 2 1 2 2 1 1 = = = = = = = = = = = = = = = = mm M d M M T N m M N m r r 35.7 3.14 150 32 672.38 10 [ ] 32 672.38 . 512.5 258.7 574.09 . 3 3 3 3 2 2 3 2 2 max =     = = + = = + =   第 19 次作业： 8-21 102 [ ] (32 20 ) 4 50 10 66.3 [ ] 3.14 20 12 50 10 2 2 3 3 bs bs bs bs A S MPa A F MPa A F      =   −   = = =     = = 8-25 166.7 [ ] 10 (80 44) 60 10 137.9 [ ] 10 (80 22) 80 10 90.9 [ ] 22 10 20 10 20 , 52.6 [ ] 22 4 20 10 20 , 4 3 2 2 2 3 1 1 1 3 2 3          =   −  = = =   −  = = =    = = = =     = = = = MPa A F MPa A F MPa A F F k N MPa A F k N F F N N b s b s b s b s b s S S S s