中心轴线对称的竖向分布荷载g().梁单位体积重为.梁的受力为平面应力问题。上述连续深梁各跨度内的应力分布是相同的,只需取其中一跨图1.11(6)进行分析就可以了.取图1.11(6)所示直角坐标系oy,测有q()=g(—)。设支座反力均匀分布于支座宽度2c上,其策度为p。取连续深梁半跨长4为参考长度,在式(1.10)无因次量的情形下,并将荷载()和支座反力集度p转化为无因次盘()=(1+-22g(), =(1+2-2) p,则图1.11(6)成为UEUE图1.1l(c),图中b/a,c/a。为了简化计算,将图1.11(c)之边界荷载分解为图1.12(a)X和()所示关于轴云对称和反对称的两种情形。图中()=(((1.10)()(z)宝装网量家(a)r真驾业A-11p(e)(5)图1.11在此情形下,控制方程与式(1.16)相同。根据问题的性质,有如下边界条件:对称荷载携形[图1.12(a)=±=0,,=0(1.84)士,,(),,注意到我(1.13),条件(1.84)可写成21
4-..3p/213P/2P/2p/22.(2)9(2)州mt7/2.p/2fpi271(2)7(r)(a)(b)图1.12元±1,-0-0,at(1.85)aaz叉一±入,- (),aayay反对称荷载情形[图1.12(6)]u=0=±1,7=0,ax(1.86)au3=±x(),Eay苏()连续深梁应力分折的边值问题综合控制方程(1.16)及边界条件(1.85)和(1.86),连续深梁的应力分析归结为如下道个偏微分方程的边值问题:对称荷载情形[图1.12(a)V=01.(1.37)f1(),,f()至一±1,其中()及()为待确定之函数。1+uaV-2.U匠(1.88)2==1,α=0;7=二入,ay1+yae3.Vsu(1.39)2=±1,=0;=入,()aray反对称荷载情形[图1.12(6)29--01.(1.90)2±1,e=g(3)e=名i(y):y=士a,其中gi(y)和g()为待确定之函数。1+u&2.u(1.91)ouJ一士人±,0:Jy花22
1+ua3.V3+27U(1.92)a元=士1,=0:二入,)at仿$1-2和$1-3中所述的方法求解边值问题(1.87)~(1.92)不难得到对称荷载情形和反对称荷载情形的解答,这里不拟赞述,直接给出有关的表达式和计算式。(二)对称荷载情形的解答1.e、立和的表达式cha/zcosa/+B,cosa.tchae4cha,cha,.282F sinaicha3 +A.Esincosy1C,sinp,zchpy台31iS3G.jB.2cosp,g()5:cospzsinay(a,H,chaa-H,)AN3)V(B,sLg/(A)3a,cosp,zg(y)-Hisha,y]_2.N(p,)g,(a)(1.93)aE.1+02p,sha,'cospE, =E,=-式中(a,+3)cha))Uα+a.F.1+"F, = sin(a.- )_ sin(a, +2)F., =3)cha.U(a2-4-3.α, +3q,G.G, - 2a' shaicospG,alty(a+3)cha.U+3a.H..sin(a,-)+sin(a-)LH.-H.=U(a,23)cna,一3a; +3,:J,j=o,:1+j= 012,j可N(2) =5(3)g/()=Ishpy,j0,chji,j#ou;-()cosp,d,a=(i-0.5)元a=(i--0.5)/A,3,-j元常数A,、B.及C.之确定2.节数A.、B:及C、由如下线性代数方程组确定:ZBXuZc,+pLrcosp, =- ZuAA,X.A2B,s2c,a,V,ch2, =- bBin1.2.3,..(1.34)U-1-3SA,Xu+B,Yai-C.p,sh3.Aa,th3.A-1cose,arLucospl-uS一X.-式中N[a'G -E],ZUYAN(B)g(A)coseLNY.u(a,Hachad-Ha')-"a,HaM,+pFaM,2XN(BSLg(A)23
P,FNuchaa,Xy(a,E,-PG,)sina,Yu thpA(a,H,cha,-H,) (βH, +a,F,)shaA, b2a'chaksina,a2sinq,aj=0.M,-2aa+aLu, :2aPchpAsinalasin(a+sin(a+2i*0,N,-a, +p,a+pa,-P,3.应力分SA『cha,icosa'y2p,E,cosP;zcosa/3]6cha!-cosa,icha;Sp,Fucospjrcha.yc.p.cosp.zchpcha,aSB / co5a-cha,7aGucha,rcosa'coszcos+7A.=N3Ccha,cha,a- acospzg/() ico[(a,Higchaa-Hy)-H,a,cha,3])N(B,)g/(A)(PLB/(A)2(PG-a Byjsingisina')-20i1B.2 aF,shay -(aHchaH)Hshasinp,2ch3.inesh2c.Bsinpshy -chp,x1(1.93)(三)支对称荷教情形的解答、及和的表达式I.STA chaisinpi2 + a, cosarshay?=ch3sha,a2csing,zsha3a.ZEsinp,cosp'y--SsF sinp,shay --区一GA31QacosB,zchp3coco5N(3.)H.acpece+ +D1cospjchayi+.N(3923sh3a-(1.96)a,F.23,sh3'cosp+uP/E.1+0FE.-E.-式中(p+chu(a-p)shaa3.2-87GJ-28/shB/.cosB9/G.1+usin(a,-p,)_sin(a+p,)F-Gu(+)chp3+?Ua+p,a;-p,sin(a,-P)sin(a+p,)a;H.1+VHH-a;+3,(a-)shaa,β,U24
aH,shaa-HQu3shpaj=o2,a,=(-0.5)元,β=in/A3,=j、V9)111j02.常数A、B.及C.之确定常效A、B.及C、由如下线性代数方程组确定:EBYu-Ec,B,l,eos, = 2uAX.--1B, 1 -EB,Ya,-Cp,N,shp,=-b1#1,2.3,*(1. 97)-SA,Xau-ZBYu, - CB.chBA=hpxa.=12C2/G. -2.E.,Xy =(g.G -- /E,c03)i-u式X正N3LAy2cospZAFuNashaja2ATa(FaM - LuQ.) -aHaM, Yom-Yu47Fa,L.cosp,gspa, N,inap+sn+e)Z-hpa:3a +3Y=(aF+H)chaa-3Q,ch3a,o-copos2p,sha.acosp.aM=-Lu37+37a+3.D,为代深梁沿轴了方问的刚佳位移,爵利用深梁的位移约束条件来确定。列如,没丝标原点处一0,则有G.广H22ANa+QD, -213.V(3)Jsha3.应力分量:chsinZ p,egcosp,irini3!子A.ch3!SB coa,sha3 +Ea,F,cose.zsha31+c.3.cos.zsh3.ysha,x-S'G.rhina小Biosazshaycos.rsing.yi+1.AVchp!sha.a!wishaylcosp3- acopehe + 27S(3R33V3sha02B,(aF, + DiH,)ehaj(E,PG)sing,cos'+1j-Zc.3ig,ienay+asinpzchpy3chsin:shp,A(1.98)利用上述解析解,我们对连续深梁的应力进行了具体的数值计算。计算分为两种情形35