材料力學(xué)總結(jié)PPT課件

1、 強強 度度 計計 算算問問 題題內(nèi)內(nèi)容容對對象象 構(gòu)構(gòu) 件件基基 本本 變變 形形組組 合合 變變 形形軸向軸向拉壓拉壓剪切剪切扭轉(zhuǎn)扭轉(zhuǎn)彎曲彎曲拉壓拉壓彎彎偏心偏心拉壓拉壓斜彎斜彎曲曲彎扭彎扭組合組合內(nèi)力內(nèi)力計算計算內(nèi)力內(nèi)力圖圖應(yīng)力應(yīng)力計算計算強度強度計算計算同基本同基本變形變形無無無無無無剛度計算剛度計算壓桿穩(wěn)定壓桿穩(wěn)定壓桿分類壓桿分類穩(wěn)定計算穩(wěn)定計算臨界力計算臨界力計算臨界應(yīng)力計算臨界應(yīng)力計算外力外力分析分析結(jié) 束一、軸向拉伸與壓縮總一、軸向拉伸與壓縮總結(jié)結(jié)2sin2sin0 p一、軸向拉伸與壓縮總結(jié)一、軸向拉伸與壓縮總結(jié)2.材料拉伸與壓縮時的力學(xué)性能1. 等截面拉(壓)桿橫截面上正應(yīng)力

2、 AFN斜截面上的總應(yīng)力：cos0p20coscos p正應(yīng)力：切應(yīng)力：3.軸向拉伸、壓縮時的變形：EAlFlN5.軸向拉伸、壓縮的靜不定問題6.剪切和擠壓的實用計算4.拉伸與壓縮時的強度條件：拉伸與壓縮時的強度條件：拉伸與壓縮時的強度條件：最大工作應(yīng)力最大工作應(yīng)力 材料極限應(yīng)力材料極限應(yīng)力塑性材料塑性材料脆性材料脆性材料強度條件：強度條件： numaxsbn1 安全因數(shù)安全因數(shù) 許用應(yīng)力許用應(yīng)力強度校核強度校核設(shè)計截面尺寸設(shè)計截面尺寸確定許用荷載確定許用荷載 maxmaxAFN maxAFN AFNmax, AFNmax,滿足滿足安全安全否則否則危險危險5010520+CABD6003005

3、00400E40kN55kN 25kN20kN(kN)50Nmax FFABCFF3000400037024021kNN50501 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 F1F2F3l1l2l3ABCDFN2 =-15kN （-）FN1 =20kN （

4、+）FN3 =- 50kN （-）15+-2050F1F2F3l1l2l3ABCDFN2 =-15kN ( - )FN1 =20kN （+）FN3 =- 50kN ( - )F1F2F3l1l2l3ABCD)(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 BCCDBllumm1

5、0-0.474- CDBCABADllll二、扭轉(zhuǎn)變形二、扭轉(zhuǎn)變形max tmaxppmaxmaxWTITIT maxppIW PIT 二、扭轉(zhuǎn)變形時切應(yīng)力：二、扭轉(zhuǎn)變形時切應(yīng)力：pmaxmaxWTpmaxWTmaxpTW pmaxWT (pddGITx xGITllddp pTlGI () prad mTlGI max ()maxmaxprad mTGI ABCMeAMeBMeC22 14 +_MPa84.6416/ )12. 0(102216/33311t11max1 dTWTMPa3 .7116/ )1 . 0(101416/333222t2max2 dTWTD+Me2Me3Me1180

6、)2(pepe GIaMGIaMMPa7 .69tmaxmax WT mkN292e M33. 2180)23(pepe GIaMGIaMCBBACA D+Me2Me3MeIyMzmaxmax WM maxmaxyIWz zzzWMyIMIMymaxmaxmaxzIMy 80y1y22020120zF1=9kNF2=4kNACBD1m1m1mFRAFRBF1=9kNF2=4kNACBD1m1m1m-+4kN2.5kNkN52R.FA kN510R.FB mkN5 . 2 MCmkN4 MB MPa2 .27t1maxtIyMzB MPa2 .46c2maxcIyMzB MPa8 .28t2ma

7、xtIyMzC 80y1y22020120z 2cos2sin22sin2cos22xyyxxyyxyx 2 22 22 22 2xyyxyx )(minmax 02tan2xyxy 02sin2cos2 2dd xyyxxyyx 2 22 21 1 tan 90901 11 1 2 22 22 2xyyx )(minmax)()()(21)(2132322214r313r3212r11r r t3ct1 Fl/2l/2Fl/2l/2S213aFzyzyFSyxzAFWT34St2 zzxWM 1 1 t1WT t3WT zyFSzyzzxWM 3 3 A alA50500 07070 xyy

8、x ,429. 10)70(50222tan0 yxxy 5 562625 527270 0. xA A MPaMPa)(minmax969626262 22 22 22 2xyyxyx MPa,MPa96960 026263 32 21 1 n3030efMPa3 .58 )60sin()50()60cos(2604026040 2sin2cos2230 xyyxyxMPa3 .18)60cos()50( )60sin(260402cos2sin230 xyyx1 16060404050502 22 22 20 0 )(tanyxxy20 0 5 567675 52

9、2220 0. MPa7 .60MPa7 .80)2(222minmaxxyxyx MPa7 .60 0 MP7 .80321 1 yxxy 2 22 20 0tan 909090902 20 0 454545450 0 45 2 22 22 22 2xyyxyx)(minmax 1 ACB(-1,-0.2)DD(-0.4,0.2)ADC BD12015152709z250kN1.6m2mABC+200kN50kN+80kNm250KN1.6m2mABCzIMy 4633mm1088 1227011112300120 zImm135 aydISFzz*S 3 32560002560005 57

10、 71501501515120120mm).(* zaS12015152709zMPa5 .122 azCayIM MPa.*S6 66464 dISFzzaa a CAB(122.5 , 64.6)D(0 , - 64.6)A1 A2MPa27MPa1502211 OAOA 4520 5 .220 MPa MPa227270 01501503 31 1 5 522220 0. a12015152709zMPa5 .136 bzCbyIM 0 b mm150 byb 0,MPa5 .136321 b(136.5 , 0)D(0 , 0)MPa20 z 40MPaxyz20MPa20MPa20M

11、PaMPaMPaMPa MPa2020202020204040 yxyxyx A1A2 O C 1 3MPamax3636 MeMeA45xyxyx 22minmax)2(2 02tan2xy EE1)(1311 3210450 451 11 EMPa2 .802121)1(2te11 WMEG 1 3AF2 WlFWM41maxmax WlFAF412maxmaxt AF2 -WMmax lFcr2l()2cr22EIFl Fcrl0.3l0.7l( . )2cr207EIFl Fcrl2cr2EIFl l 22cr)(lEIF lFcrl/4l/4l/2( / )2cr22EIFl l 22crlEIF 22cr)7 . 0(lEIF 22cr)5 . 0(lEIF 22cr)2(lEIF 22cr)(lEIF 22cr)(lEIF AlEIAF22crcr)( ()()(/ )2222crcr222FEIEEiAlAll iil AIi 22cr E crcrAF 2crp2 E 1pE 2p E 916p206 10100200 10E scr ba 12 ba