材料力学总结PPT课件

1、 强强 度度 计计 算算问问 题题内内容容对对象象 构构 件件基基 本本 变变 形形组组 合合 变变 形形轴向轴向拉压拉压剪切剪切扭转扭转弯曲弯曲拉压拉压弯弯偏心偏心拉压拉压斜弯斜弯曲曲弯扭弯扭组合组合内力内力计算计算内力内力图图应力应力计算计算强度强度计算计算同基本同基本变形变形无无无无无无刚度计算刚度计算压杆稳定压杆稳定压杆分类压杆分类稳定计算稳定计算临界力计算临界力计算临界应力计算临界应力计算外力外力分析分析结 束一、轴向拉伸与压缩总一、轴向拉伸与压缩总结结2sin2sin0 p一、轴向拉伸与压缩总结一、轴向拉伸与压缩总结2.材料拉伸与压缩时的力学性能1. 等截面拉(压)杆横截面上正应力

2、 AFN斜截面上的总应力：cos0p20coscos p正应力：切应力：3.轴向拉伸、压缩时的变形：EAlFlN5.轴向拉伸、压缩的静不定问题6.剪切和挤压的实用计算4.拉伸与压缩时的强度条件：拉伸与压缩时的强度条件：拉伸与压缩时的强度条件：最大工作应力最大工作应力 材料极限应力材料极限应力塑性材料塑性材料脆性材料脆性材料强度条件：强度条件： numaxsbn1 安全因数安全因数 许用应力许用应力强度校核强度校核设计截面尺寸设计截面尺寸确定许用荷载确定许用荷载 maxmaxAFN maxAFN AFNmax, AFNmax,满足满足安全安全否则否则危险危险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、扭转变形二、扭转变形max tmaxppmaxmaxWTITIT maxppIW PIT 二、扭转变形时切应力：二、扭转变形时切应力：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