第17次作业: 8-1 M=EL+F-3kNmm -el=0.8kn m 2 W=102cm3,W,=16.lcm 3×1060.8×10° W102×10316.1×10 294+791=128.8MPa 8-5 F FN F=-21.65kN.M==1625kNm A=306cm2,W=185cm3 FM21.65×10316.25×10 185×10 708+874=949MPa(压应力) 8-7 Fx=16kN,M=16×0.14=224kNn F 6M 第18次作业: F Fe 4F 32F6 [ mEx A w nd2 nd3 -s[] -=140.5kN 4(d+32e) 8-16 52 F 4=2xx×0 0.3925kN M=F×0.8=0.314kNm,T=F×06=02355kNm M2+T232×0.3925×10° xx60(-a)s60→a=0.91185 60-54.7 =265mm 8-18
第 17 次作业： 8-1 MPa W M W M W cm W cm k N m M F l k N m Fl M Fl y y z z z y z y 29.4 79.1 128.8 16.1 10 0.8 10 102 10 3 10 102 , 16.1 3 . , 0.8 . 2 3 6 3 6 max 3 3 2 1 1 = + = + = + = = = = + = = = 8-5 7.08 87.4 94.9 (压应力） 185 10 16.25 10 30.6 10 21.65 10 30.6 , 185 16.25 . 4 21.65 , 2 3 3 6 2 3 max 2 3 MPa W M A F A cm W cm k N m Fl F F k N M z N z N = + = + = + = = = = − = − = = 8-7 b mm ab M ab F F kN M kN m N N [ ], 86 6 16 , 16 0.14 2.24 . max 2 = + = = = = 第 18 次作业： 8-11 kN d e d F d Fe d F W Fe A F t 140.5 4( 32 ) [ ] [ ] [ ] 4 32 3 max 2 3 = + = = + = + 8-16 mm W M T M F k N m T F k N m F pA k N r 2.65 2 60 54.7 60 0.91185 60 (1 ) 32 0.3925 10 0.8 0.314 . , 0.6 0.2355 . 0.3925 4 0.5 2 3 4 2 2 6 3 2 = − = = − = + = = = = = = = = 8-18
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