材料力学第八章组合变形-2015正式

1、12 345= =+ + += =+ +6 7O 8AFN zzIyM zzIyMAF N O92NFF l/2l/241maxlFM xxFN图图M图图F2F1l/4 10AF2 WlFWM41maxmax WlFAF412maxmaxt AF2 -WMmax 11max tmaxt cmaxc 12FACD1.2m1.2mB30FFRAyFRAxFNBC3002 . 14 . 230sin0FFMBCAN FFBCNFFFFFFFFFNBCAyyNBCAxx5 . 030sin0866. 030cos000RR13AFAFAx866. 0R zzAyWFWF6 . 02 . 1Rmax M

2、Pa37.946 . 0866. 0maxc zWFAFFACD1.2m1.2m30BFFRAyFRAxFyxFNAB30FFFFAyAx5 . 0866. 0 RR AB梁满足强度要求。梁满足强度要求。14yzz0z15050150150350FF15yzz0z15050150150350FF16nnFNMyyFFMFFy22N105 .4210)5 . 735( yzz0z15050150150350FF17MPa15NFAF nnFNMyyzz0z1505015018)(MPa53105 . 74250maxt FIzMyy)(MPa53105 .124251maxc FIzMyy505

3、0150150yzz0z1拉拉nnFNMy1953105 . 742515tmaxtmaxt FF5050150150yzz0z1拉拉压压nnFNMy2053105 .12425cmaxcmaxc FAF5050150150yzz0z1拉拉压压nnFNMy21aaaa221122N14)2(aFaFAFAF aa22N222612/2aFaaFaaaFWMAF 8 84 42 22 22 2 aFaF/23O1yzFA(yF,zF)24 eO1yzA(yF,zF)FFzFyFyMFZM (yF,ZF)25yzO1Fx26 yO1nnyzMyMz FzFyFyMFzMF27yzMyMzAFAF

4、N yFyyIzzFIzM zFzzIyyFIyM (y,z)C28 ,zFyFIyyFIzzFAF yzMyMz(y,z)C29zFyFIyyFIzzFAF 22zzyyiAIiAI )1(22zFyFiyyizzAF 30012020 zFyFiyyizzOz中性轴中性轴)1(22zFyFiyyizzAF 31中性轴中性轴(yF , zF )012020 zFyFiyyizzFyzFzyziayia22 yz32O中性轴中性轴外力作用点外力作用点中性轴中性轴1(1,1)2(2,2)33(abcyyzzyzFyF/WzNF yM zM FzF/Wy34yz1D2中性轴中性轴zFyFWyFWz

5、FAF minmax max 35laABCF36BFMxlaABC37AAFMMFl38A截面截面 C3C4TC3C4C2C1 C2C1139C1 2222314212)2(2 02 422313r 2243r 2 22 22 22 2xyyxyx )(minmax40 22313r4 224r3141 WTMWTWM2222223)(4)(4tr WTMWTWM222222475. 0)( 3)(3tr132 23dWWWt 42ABCD1.4m0.6m15kN10kN0.8mABFemkN e156 . 0104 . 115MkN251510F43ABFMe+15kNm-20kNmmkN

6、20max MmkN15 T)1(3243 DWMPa26.157223r WTMTMAB杆满足第三强度理论杆满足第三强度理论44BACDyz5kN10kN300mm300mm100mmx1.82kN3.64kNCD45BACDyz5kN10kN300mm300mm100mmx1.82kN3.64kNxyzACBD5kN1kNm1.82kN3.64kN10kN1kNm461CT 图图-My0.57CB0.36xyzACBD5kN1kNm1.82kN3.64kN10kN1kNm0.57kN m-0.36kN myCyBMMmkN1mkN227. 0 zBzCMMMz0.2271CB47mkN22

7、7. 0mkN57. 0 zCyCMMCT图图-My图图0.57kNmCB0.36kNm-0.36kN m1kN myBzBMMmkN1 CBTTmkN063. 122 zByBBMMMmkN61. 022 zCyCCMMMMz图图0.2271CB48 WWTMBB137275. 0224r323dW .3632 137251 9mm100 10d 4940050400400400mkN4 . 0kN1e2 MFmkN4 . 0mkN8 . 04 . 08 . 0max21max TFFM WTM2max2max3rmm5 .38 d51400400400mkN4 . 0mkN8 . 04 . 08 . 0max21max TFFMkN203N FF52400400400MPa143Nmaxmax AFWMz MPa8 .31tmaxmax WT MPa1574223r53作业：作业：8-6/8/11/ 8-14（第四强度理论）（第四强度理论）/15/2454yzebhmm55yze2 21 1FFF eFMz 221FFF eFMz 256AFFAF21N 6/22bheFWMzz 06/2221 bheFAFF6/ )(2212bhFAFFe