材料力学第二章

1、Chapter2 Chapter2 FFFFmmFFmmFFNmmFFmmFFmmFFNFNmmFFmmFFNmFmFNmFFmmFFNmFmxFNOCABD600300500400E40kN55kN 25kN20kNCABD600300500400E40kN55kN 25kN20kNCABDE40kN55kN 25kN20kNFRAkN100202555400RR AAxFFFCABDE40kN55kN 25kN20kN10R1N AFF)()kN(10R1N AFF F40kNFN220kNCABDE40kN55kN 25kNF2040R2N AFF)()kN(5040R2N AFFFN3

2、20kN25kNCABDE40kN55kN 25kN20kNF30 0202025253 3 NF)()kN(53N F20kNFN440kN55kN 25kN20kNF4)(kN)204N F5010520+CABD600300500400E40kN55kN 25kN20kN(kN)50Nmax FFFabcdFFabcda b c d F FNAFN Fkk F coscos AFAFpFkkFp AFp cosAA FF 2coscosp sinsin22p Fkk FFkkxn p Fkk FFkkxn p max2 2 max2 2 min0 00 0 ,2coscospsinsin

3、22p xnFkk Nmaxmax AFNmax FA NmaxAF AFmaxN FABCFF3000400037024021kNN50501 1 FFkNN1501503 32 2 FFFABCFF300040003702402150kN150kNMPa.N/m.2N87870 0101087870 024240 024240 050000500006 61 11 11 1 AF MPa.N/m.2N1 11 110101 11 137370 037370 01500001500006 62 22 22 2 AF max ABCF1mABCF1mFAxyFAxy0 030300 01 1

4、FFFysinN0 00 01 12 2 cos30NNFFFxFFFF7327321 12 22 21 1.NN 22mm6 62 26 61 11010286028602 2143014301010217221722 210861086 AAAFmaxN FFFF732. 122N1N kN.N24243693691 11 1 AF kN.N20204864862 22 2 AF kN.N6 61841842 21 11 1 FFkN.N7 72802807327321 12 22 2 FF2aaFABDC2aaFABDCCDFACBFFMCDA230N /N232119MPa4CDFFA

5、d N AFCDCDF=33.5kN2aaFABDCCDFACB2 23 3FAFCD N N AFCDCD/N 2 23 3FFACD / 2324dF dl标距标距FOlefhabcddgfl0 p E p fOfhae p fOfhab es s b b e p fOfhabce s b e p fOfhabce %1001001 1 lll %1001001 1 AAA abcefOgfhddpe abcdefOdgfhd 0.2 0.20.2% tan E2 20 0. oO /MPa/% dh0 03 35 51 1. dh sO O /% nu ssn bbn max max m

6、ax max Kmax FFbh h1 lllll 1 1bbbbb 1 1 FFbhh1 bbb 1 AFN ll E EAlFlN F1F2F3l1l2l3ABCDF1F2F3l1l2l3ABCDF1FN1)(kN2001N1N1 FFFF2F1FN2F1F2F3l1l2l3ABCD)(kN1502N2N21 FFFFFFN3)(kN5003NR3N FFFDFN2 =-15kN （-）FN1 =20kN （+）FN3 =- 50kN （-）15+-2050F1F2F3l1l2l3ABCDFN2 =-15kN ( - )FN1 =20kN （+）FN3 =- 50kN ( - )F1F2F

7、3l1l2l3ABCD)(MPa.N 8 81761761 11 1AFAB )(MPa.N 6 674742 22 2AFBC )(MPa.N 5 51101103 33 3AFDC F1F2F3l1l2l3ABCDm102.534-N 1 11 11 1EAlFlABm101.424-N 2 22 22 2EAlFlBCm101.584-N 3 33 33 3EAlFlCD-0.3mm BCCDBllumm10-0.474- CDBCABADllllABC12 ABC12 , ,FyA12 x0coscos00sinsin02N1N1N2N FFFFFFFyx cos22N1NFFF AA

8、BC12 ABC12 cosNEAFlEAlFll2 21 11 12 21 1 ABC12 A A2 2A1Al 1 12AAAAA )(mm293. 1cos2cos21 EAFllAAAF FA12x30yA1 1l 12mABCF301 12 2FFFF732. 122N1N A2 2l 2mm.mm.NN7657650 01981981 12 22 22 22 22 21 11 11 11 11 1 EAlFlAAEAlFlAA3030AA1A2l 1l 2A30A1 1l 12mABCF301 12 2A2 2l 2A330cos1222llAAAAAA 30sin30tantan

9、3012232llAAAA mm.)()(78783 32 23 32 22 22 23 3 AAAAAACABDF 1 12 23 3xyFA 2 21 10 0NNFFFx 0coscos03N2N1N FFFFFy CABDF 1 12 23 3xyFA CABD 1 12 23 33 3l A1 12 23 3 CABDF 1 12 23 3CABD 1 12 23 31 1l cos3 31 1ll 1 11 11 11 1EAlFlN 3 33 33 33 3AElFl cosN 2 23 33 33 31 1cosNNAEEAFF CABDF 1 12 23 33 3l A1 1

10、2 23 3 1 1l 2 23 33 32 21 12 21 1coscosNNAEAEFFF 2 21 1NNFF 0 03 32 21 1 FFFFNNNcoscos 2 23 33 33 31 1cosNNAEEAFF 2 23 33 33 32 21 1cosNAEEAFF ABCF3aal21ABCF3aal21FABC3aa21FN1FN2FN3F 0 xF0 xF 0 0yF03N2N1N FFFF 0 0BM0 02 22 21 1 aFaFNNABCF3aal21ABCl 3l 2l 1ABC3212 23 31 12 2 lll 1 11 11 11 1EAlFlN EA

11、lFl3 33 3N EAlFl2 22 2N 2 23 31 12 2NNNFFF ABCF3aal21ABCl 3l 2l 1ABC321N2N3N1FFF2 2 0 0 xF0 0 FFFFN3N2N102N2N1 aFaF6/53/6/N3N2N1FFFFFF AABCD 2 21 13 3l AABCD 2 21 13 3ll 3l 13 3l1l3l 1cosl cos1 13 3ll3 33 33 31 11 11 1AElFlAElFlN3N1cos AABCD 2 21 13 3ll 3 l 1 2 21 11 13 33 3cosN1N3AElFAElF0coscos0si

12、nsinN2N1N3N2N1 FFFFF ABC12aaB1A1C1l3C1Cl3C1CABC12B1C1A1ell 3 31 1aaxEAlFl1 11 1N1 3 33 33 3AElFlN3 AElFeAElFN1N3 3 33 3CAB0 0 N2N1N3FFFN2N1FF AB ABABB0 0 lABABAB0 0 FTlllEAlFlBFR lTllT EAlFlTBlR TEAFlBR TEAFlBTR BAB（FFFFFFmFFAB d 1 1 1nnFFnnFFmmF剪切面剪切面FS FFmm00S FFFxFF SAFS mmF剪切面剪切面FFmm AFSnu u FFFFFF bsbsbs AFAFbsbs hbsAdh bsbs FA bsbs SFA AFbsbs SFA u bhlMeFMee2MdF kNe57571010707010102 22 22 23 33 3 dMF MPa6 .281010020105763SblFAFFF S bsbsbsMPa. 3 3959510106 6100100101057572 26 63 3hlFAFMeFbhl 1FFA 1Bd 1FFA 1Bdd2F2FF剪切面剪切面d2F2FFF2SFF 24dA MPa51SAF1 2 bsbsb