工程力学组合受力及变形时的强度计算

1、Nanjing University of TechnologyNanjing University of Technology PzPyC()PPPPyzsincosPzPyC()sincosyzPPPzyP以 为中性轴弯曲以 为中性轴弯曲()cos ()cos()sin ()sinyzzyMP lxPlxMMP lxPlxM M yIM yIzzzsin MzIM zIyyycos M yIM yIzzzsin MzIM zIyyycosPMyzPMzy cossinyzcIzIyM000 MyIzIzysincossincosIyIzzy0001D2DtgtgzyIIyz00 )coss

2、in(2, 12, 1maxzIyIMyz yzMzMmaxMmaxM22maxyzMMMWW22maxyzMMMWW cossinPPPPFFFFyz,dc4sin4PPPmaxlFlFFMxz4cos4)(PPPmaxlFlFFMyy+d+czyyzWFMWFMcbPmaxPmaxmax,zyWlFWlF4cos4sinPPmaxMmaxM max217 8MPa160MPab c ,.30 22max0.96 sin303.60.78kN m88zyqlM22max0.96 cos303.61.35kN m88yzq lM maxmaxmaxyzyzMMWW2266yzhbWbhWh/b

3、=3/2b=0.0876mh=0.131mb=90mm h=135mmmaxmax NFAzMyINzFMyAI注意中性轴的偏移情况，最大正应力点的位注意中性轴的偏移情况，最大正应力点的位置及其数值，正负号置及其数值，正负号MWNFAMW max 0 xF 0CM 7.07MPaPa107.07Pa1012800446622NNNdFAFxxxxF70.7MPaPa1070.7Pa10121232326633maxdMWMMzzzzxMPa877Nmax.FzxxxxMMPa663Nmax.FzxxxxM00NzzxxIyMAF0.6mmm100.6m1264101280044643-6224

4、NN0dMdFAMIFyzxzzx10KN1.2m1.6m1.6mABCXYAA34kNkN任意横截面 上的内力x:3kN4kN( )4NAAAFXQYM xYxx 1 13kN8kN mNFM 截面上危险截面，其上：，33max23max81.13 108 10MPa81.9432NFMddAW 位置？位置？5kNXA10KN5kNYAxBAC3454cm10360128kNNFP36128 10Pa40MPa320 10 10NNFA32128 102 10 N mM 262560Pa15MPa10 320106MMWN40MPaM15MPamax55MPaNMmin25MPaNM4cmP

5、P两侧开口时是轴向拉伸两侧开口时是轴向拉伸360103max6128 10Pa45.7MPa280 10 10NNFA128kNNFP本题中：两侧开口好于一侧开口，为什么？本题中：两侧开口好于一侧开口，为什么？1.5m2.5mDCBA60AXAYCDF0AM25.6kNCDFCXsin6022.17kNCCDXF12kNm22.17kN maxmaxmax3322.17 1012 10NFMAWAW 100MPa 33maxmaxmax22.17 1012 10100MPaNFMAWAW2230.6 10 mmA33185 10 mmW max72.1MPa2226.1 10 mmA 3314

6、1 10 mmW max93.6MPaOxzyTMyMzOxzyTMyMzM P,MTWW16323P3dWdW, 2214212223421202 2231421323222121 223 224 223 22MTW 220.75MTW22222r3yzMMTTMM22222r40.750.75yzMMTTMM WM3r WM4r注意：注意：mN2120r/min715kW995499549e.nPMe120.2N mMePP222MDFDFN696110mm250mN2120223eP.DMF -3maxRPe33 961.6N 120mm 10346.2N m120.2N mMFlFlT

7、M 22223-3346.2N m120.2N m 40mm 103258.32MPaMTWFP5 kNMeFPa1500 Nm MzFPb2500 NmTMeFPa1500 Nm 32233r1010 xzMMMd59.3mmm0593010MPa140mN1500mN2500103622. 22r433100 7510.zxMMMd52.2mmm0522010MPa140mN1500750mN2500103622.7.595499549716.2N m100PTn12()2PPDTFF1213900N5400NPpPFFF，5400N716.2Nm716.2Nm5400N716.2Nm71

8、6.2NmMzB=3600 0.4=1440NmMyB=1120 0.4=448NmMyD=1120 1.2=1440NmMzMyT=716.2Nm 22maxwBzyMMMMT22222330.7161.440.448101669N mrwMMT33 rrMW333363232 166959.7 10 m 80 10rMd t100101002001050000201620362.MPaAA=QA= QAbsbs=FAAt dbs bsbsbs=FA bsbs maxPdh ( ) 1( )( ) .12424得：dhPd242 ( )bsPDd440104402042422322()(). MPaPdh401020106373. MPaPAbminba t64 2157.5kN22PQ P2t QA42675002.510m 3010QA2ttt2442.5 10