课后答案详解

1、6. 1解:-450X121 .计算截面特征值工字形截面A=20x500x2+12x450=25400mm23384Ix=500x490/12-488X450/12=11.9629x10mm；384Iy=2x500X2O/12=4.16610mm4mm；ix=217mm；iy=128mm；2 .刚度验算x=6000/217=27.65;初二46.88Zx、Zy打刚度满足要求3 .强度验算因无截面稍弱无需验算截面强度4 .整体稳定验算：焊接工字形截面翼缘焰切边x、y轴都属于b类截面in=*y=0.8704322G=N/锹=4500X10/(0.8704X25400)=203.54N/mmf=20

2、5N/mm杆件整体稳定满足要求5 局部稳定验算：翼缘bi/t=244/20=12.2(10+0.1a)(235/fy)，2=14.69腹板ho/tw=450/12=37.580/12=13.3619X10mm；1二250咒20/12=3.0375咒10mm；ix=228.1mm；iy=113.07mm；/x=6000/236.5=26.3;=3000/112.5=26.53x、/y23760)=199.78N/mmf=205N/mm整体稳定满足要求板件局部稳定验算：泳、/.y30取/=30翼缘bi/t=219/20=10.95(10+0.11/2-一13扎)(235/fy)1/2-腹板ho/t

3、产480/12=407y由b类兀查得0.9153322o=N/瓠二4500X10/(0.9153X25150)-195.48N/mmf=205N/mm(25150-23760)/23760=5.85%翼缘bi/t=193.5/21=9.21(10+0.1A)(235/fy)1/2=13.57腹板ho/t产358/21=177x由b类zy查得0.SS1bN/牡=4500X103/(0.88123550)=216.89N/mm2f整体稳定不满足要求(两个方向长细相差较大)选HN800300(792X300)A=24340mm2lx=25.dXlOmm1；Iy=0.993103mm；ix=323mm

4、：iy=63.9mm；/x=6000/323=18.58；3000/63.9=46.95分由b类养j查得0.87CN/%=4500X107(0.87邈4340)=212.51N/mm2f整体稳定满足要求翼缘bi/t=143/22=6.5(25+0.5/)(235/fy)1/2=48.48腹板局部稳定不满足要求6.3解:rz10(fl)(l)A=320；c2+10c320=16000mm23384lx=320X360/12-310咒320/12=3.9723x10mm；384Iy=2x320x20/12=l.0923x10mm；ix=157.6mm；iy=82.6mm；兀二10000/157.6

5、=63.5;=10000/82.6=121.1焊接工字形截面翼缘为剪切边X、y轴分别属于b、c类截面氧二0.7885半y=0.3746ain=%=0.3746N二fA=205x(0.3746X16000)=1228.69kN(1230)翼缘bi/t=155/20=7.75432/12-392X400/12=5.9645X10mm；ly=2X4OO3X16/12=1.7067X108mm!；ix=193.lmm;iy=103.2mm;Zx=10000/193.1=51.8;Zy=10000/103.2=96.9焊接工字形截面翼缘为剪切边X、y轴分别属于b、c类截面骸二0848%=0.4776幅i

6、n二y=0.4776N=f申A=215X(0.4776X16000)=1642.94kN(1230)翼缘bi/t=196/16=12.25215=2772mm2ix=lox/)=2300X80=28.75mm；i=1oy/k=287OSO=35.88mmh=ib=iy/0.215=167mmx/0.305=94mm；选L100X7A=13.82=27.6cm233.09cmiy=4.53cm/x=230/3.09=74.43)y=287/4.53=63.36b/t=100/7=14.29dO7(O.72352760)=205.32N/mm2f=215N/mm2满足要求局部稳定b/t=100/7

7、=14.29215=9222mm2柱上端较接，下端固接。产0.7x7500=5250mmi=l/=5250/60=87.5mm；hti/O.38=230mm；b/0.44=199mm由A和i选32a；A=48.512=97.02cm2iy=12.5cm/y=1oy/iy=525/12.5=42由等稳得:/ypx、l、!-r-tvtI.得：加仃山孑)s/IC.5亦ax=0.542=21或40取)1=20a=(F-F)1/2=36.93ix=lOx/ix=5250/36.93=142b超0.44=323mm取b320Zo2.24cmIx=2(305+13.76248.51)=1.SgSlOcm*i

8、s=13.99cm/x=525/14=37.5ii=2.50cmlo壬/iii=20X25=500mm取lo=5OOzj=500/25=20221/2221/2/ox=(fx+/!)=(37.5+20)=42.5由/,ox=42.5按b类查得取=0.889322ON/獗=1600X10/(0.8899702)=185.51N/mm6缀板面的剪力Vi=(Af/85)(fy/235)”1/2=(9702X215)/85/2=12.270kN缀板的内力为剪力Vj=ViIi/bi=12270685/275=30.563kN弯矩Mj=Vi11/2=12270X685/2=4.202kN.m(还要验算缀板

9、强度及连接焊缝，而且要画图表示)o6.6解：假定6=60按b类查得知0.807A=N/聊=1600X1070.807X215=9222mm2柱上端钱接，下端固接。1ox=lo.z=O.7X7500=5250mmi=l/Z=5250/60=87.5mm；i/0.4=219mm；b=i/0.5=175mm由A和i选I22b；A=46.632=93.26cm2i=8.78cmfy=1o,/iy=525/8.78=59.79由等稳得：/y=/.ox得：/x=，-27A/A10彳选缀条的角钢L45X4Aix=20.49cm/x=(59.79-2746.63/3.49)1/2=56.69ix=l“/x=5

10、250/56.69=92.68%工/O.5=185.22mm(取b=220mm肢件轴线距离bi=108mm244ix=58o5cinlx=2(239+5.4:x46.63)=0.3197x10cm1/x=525/14=89.66太大，不满足等稳要求取b=300mm肢件轴线距离bi=188mmlx=2(239+9.4:X46.63)=0.8718i=9.67cmXIOcm4/x=525/9.67=54.321/221/2/ox=(/x+27A/Aix)=(54.3+27x46.63/3.49)=57.53v初由为=59.79按b类查得qx=0.8100=N/探=1600X107(0.810X93

11、26)=2U.81N/mm2f=215N/mm2构件整体稳定和刚度满足要求分肢稳定：缀条按45啼置l0i=2X188=376mm)1=37.6/2.27=16.56v0.7).max=0.7X59.79=41.85分肢稳定满足要求A/Q缀件面的剪力Vi=(Af/85)(fy/235)/2=(9702X215)/85/2=12.270kN斜缀条内力MV/cosot斜缀条按轴心压杆计算，考虑偏心的影响乘折减系数。(要验算斜缀条的强度、稳定以及连接焊缝，还要画图表示)6.8解：145aA=10245mmlx=3.22xlOsmm!；ly=8.SSxlO61；Wx=MSxlOmm3；ix=177mm；

12、iy=28.9mm；杆长5m,两端钱接，杆中点侧向有一侧向支承。(1)强度验算：M=Ne=380X0.5=190kN.mc=N/An+Mx/Wnx=N/An+Mx/Wnx=380X10710245+380X0.5X1071.05X14310=37.09+126.54=163.63N/mmf=205赭im(2)平面内稳定验算：7x=5000/177=28.25b/h=l50/450=0.3330.8按a类截面查得%=0.9655222326Nex二兀EA心.1”兀X206X10X10245心,1X28.25)=23.73X10N,PmxMx孑,一十-dYxWxi1-0.8jNEX380X103.

13、190X106十3、0.9655X10245L-38oxiO1.05X143X101_0.8I23.73X10/=38.42+128.18=166.90N/mmcl8)=3.8513(235/fy)腹板边缘的应力00ACFN/AWx/XWnxiiN/An+Mx/ixWw380X10/10245190X10/1410=37.09132.87=169.96(-95.78)N/mm2f01oNomax-bminlbmax=(169.96+95.78)/169.96=1.566ho/tw=414/l1.5=3689.ll2+3002090,892=1.5712咒10,mm1；ly=20X300712+

14、185x340/12=45.1652X106mm4；ix=113.86mm；iy=61.05mm；863Wix=Ix/(90.89+10)=1.5712X10/100.89=1.5573X10mm；853W2x=1.5712X10/259.11=6.0638X10mm；(2)强度验算：Mi=Nei=900X0.15=135kN.m；M2=Ne2=9000.l=90kN.m；翼缘背0=N/An+Mx/痛iWnx=N/An+Mx/XWnx=900X10712120+135X106/l.05咒1.5573z/0622=74.26+82.56=156.82N/mmf=205N/mm腹板尖G=N/An-

15、Mx/X2W*N/AMx/W*900x10712120-135x1071.2X6.0638X10522=74.26-185.53=-lll.37N/mmf=205N/mm截面拉压强度都满足要求(3)平面/陆勖(则皴86二70.26刀=150按b类截面查得qx=0.749pmx=0.65+0.35M2/M1=0.65+0.35x90/135=0.883Nex=；i2EA心.1Zx2)=；fx206xl03X12120心.1x70.262)=4.538X106N+mxMx取AWxi1-0.8N,0fdvnExJ22=99.14+86.65=185.79N/mmf=205N/mm验算腹板尖受拉N丈f

16、900 X10，0.749x12120A一加2h_1.25二vNex%0.883xn5Xl(?屏900X103)1.05XI.5573X1061-0.8614.538X10)900 X1030. 883X135 X10612:2012叵I三石=174.26-217.821=143.56N/mm2f=205N/mm2平面内稳定满足要求(4)平面外稳定验算：).y=4000/6105=65.53刀=150按b类截面查得笑二0.7765两板组成的T形截面了022%=1BO.0022X65.53=0.8558(侧向支撑点间的弯矩)ptx=O.65+0.35M2/Mi=0.65+0.35X112.5/1

17、35=0.9422 2=95.63+95.42=191.05N/mmf=205N/mm平面外的稳定满足要求3 6900x10+0.942x135x100.7765x121200.8558咒1.5573咒106(5)板件局部稳定：1/2bi/t=141/20=7.0513(235/fy)(P238书中解释为什么可采用轴心压杆计算公式)腹板自由边受拉，偏安全采用轴心压杆的计算公式：1/2ho/t产340/18=18.89(13+0.17打(235/fy)=(13+0.T70.26)=24.94局部稳定满足要求。6.11解：L/L100X8rrr11x!50aX.1500-J75截面绕虚轴弯曲N=1

18、700kN,Mx=：OOOkN.m150a截面特性A=119.3cm2；Ix=46500cm1；ix=19.7cm;1k1122cm；iy=3.07(1)截面特性24A=119.3X2=238.6cm；ly=46500X2=93000cm；244Ix=2(1122+75X119.3)=134.4369X10cm；ix=75.1cm；Wx=Ix/y=134.4369咒10/(75+7.9)=1.62168X10;cm3；(2)强度验算：格构式按边缘屈服准则0o%。=N/An+Mx/Wnx=N/An+Mx/Wnx=1700X10/23860+2000X10/1.62168X10=71.25+123.33=194.58N/mm2f=205N/mm2(3)平面内稳定验算：7x=1980/75.1=26.36刀=150)ox=(ix2+27A/Aix)1J(26.36斗27咒119.3/15.64)1/2=