《【材料力學(xué) 課件】PPT-第五章 彎曲應(yīng)力》由會(huì)員分享,可在線閱讀,更多相關(guān)《【材料力學(xué) 課件】PPT-第五章 彎曲應(yīng)力(49頁珍藏版)》請(qǐng)?jiān)谘b配圖網(wǎng)上搜索。
1、 mm Mmm m m M + +F F+FaF Fa aC DA B 中 性 軸 dxyz xO d yz y xO Ob byb bOOxbb d OO OO d yy d dd)( d)( ybb y zO xE yE y z xOM zy FNMzMy dA dA zy AA AF dd NNF iyMizM AA y AzM dd AA z AyM dd 0 0 M NdF yMd zMd Ad zIEM1 0dN AyEF A 0d A AyE 0d A AyzS0d AyzEM Aiy 0d A AyzE 0d A AyzyzIMAyyEM Aiz d MIE z MAyE A
2、d2 zEIM1 yE zIMy 討 論IyM zmaxmax WM maxmaxyIW z bh zy zdy zDdy322/ 64/2/ 34 ddddIW z 62/ 12/2/ 23 bhhbhhIW z DdDW )1(32 43 zyy maxcy maxt My maxty maxc zIMy maxc tmax IMy zmaxcmaxc IMy zmaxtmaxt WxM )( 5/ hl maxmax WM maxMW max WM max WM ct maxcmaxt tmaxt cmaxc A CB Fa2a 203014FRA FRB Fa433 cm07.112
3、)cm2)(cm4.1(12 )cm2)(cm3( zI 34max cm07.11cmcm07.1 yIW zz max WM z kN3 aWF WFa z z 80y 1y 2 20 20120zF1=9kN F2=4kNA C B D1m 1m 1m FRA FRBF1=9kN F2=4kNA C B D1m 1m 1m-+ 4kN2.5kN kN52R .F A kN510R .F B mkN5.2 MC mkN4 MB MPa2.27 t1maxt I yM zB MPa2.46 c2maxc I yM zB MPa8.28 t2maxt I yM zC 80y 1y 2 20 2
4、0120z zbFl hnbhFlnhb lnFWM z 22maxmax 6)(61nF / zbFl hbhFlbhFlWM z 22maxmax 661 q(x)F1 F2 q(x)F1 F2 mm nnx dxm nnm xyz O b dxmmh ny A BA1 B1A BB1A1 m nxz yy FN2FN1 m nnm xyz Oy A BA1 B1b dxmmh n A BB1A1 m nxz yyFN1 FN2dFS A BB1A1 m nxz yy mFN1 FN2dFS 1 d11N A AF AyIMAIMy AzA z dd 11 11 zz SIM zzA SI
5、 MMAF dd1 22N 1 d1Az AyS Ad1 zz SIMF 1N zz SI MMF d2N xbF dd s 0 xF 0d S1N2N FFFbISxM z z dd Sdd FxM bI SFz zS A BB1A1 m nxz yy mFN2 FN1dFSAd1 b bI SF z zS yA* zzISz Sz yd 1y1 nBmA xyz Oy A1 B1m1 1 d1Az AyS )4(2d 2212/ 1 yhbAbyhy )4(2 22SS yhIFbI SF zz z zbhFbhhFIhF z S32S2Smax 231288 AF23 Smax zy A
6、z yAAyS d H o y xbzhbI SF z zS * y Oz y dxyA*dI SFz zS Sz* 8)(8 22Smax hbBBHbIFz oz yminmax bhFS dISF zzS *maxmax Sz*max ydz O k Ok Oz y ydz O kOkAFbI SF z z S*Smax 34 24dA z yr0 z yr0 AFSmax 2 max Smax *maxmax bI SF z z F+37.5 kNm5mA B2.5m F CmkN5.37max M 3cm237W z MPa158maxmax WM z +FSmax 5mA BF C
7、kN30RmaxS FFF Acm2.17*max SIz z MPa9.24 *maxmaxSmax dI SF z z q BA C DElF Fa a8kN210kN 208kN41.8 kNm 41.8 kNm45 kNm363max cm28110160 1045 MWz ,cm9.18*max z zSIMPa100MPa148 1075.0109.18 10210 22 3maxmaxSmax bI SF z z ,cm9.18*max z zSI MPa100MPa6.98101103.21 10210 22 3max 2.2m 200z 220120 10 4cm2370zI
8、 62.5kNm2.2mF1.41m 2.5m 5mA BCD1.4m FRBFRAmkN5.62max M 200z 220 120 1048m105020 10)5110(120 102102730 128 zI m10456 36max yIW zz maxcmax 137MPazMW 2.2mF1.41m 2.5m 5mA BCD1.4m FRBFRA 50.4 kNmmkN4.50 lFabMD cm237 3W z MP213max aWM zDD SmaxF F maxmax WM z Fl F a alqlq 32 31 DWz )2/(,4 1221 DaaD 1322 1.
9、18 6 )(6 zz WRbhW zD za aa 12a 1 z112121 2,24 DaaD 13123 67.1 646 zz WabhW 12222221 05.1,6.18.024 DaaaD 14 57.4 zz WW 0.8a2a21.6a 22a 2 z FbhWW 21 b h123 1 bhW b h 1232 hbW z max 1 t1 max 2 c2z zyM y I yM y Itmaxcmax bh(x) zFl/2 l/2 )()61( )2()( )( 2max xbh xFxW xM 3)( bFxxh 22323 minSmax bhFAF 43min bFh bh(x) zFl/2 l/2 3)( bFxxh F