薄城曲 B点的挠度为w+ x D的挠度为w+h Oy Ow 由=0和=0知+ax=0 =0 azOy du 或写成 O 对进行积分,并利用(l)=0.()=0,得 Ox au aw 于是应变分量用w表示为:Ex 2 aw 8…= 2 au 16 e Oy ax Oxay
16 B点的挠度为 dx x w w + D点的挠度为 dy y w w + 由 xz = 0 和 yz = 0 可知 0, = 0 + = + y w z v x w z u 或写成 y w z v x w z u = − = − , 对z进行积分，并利用 (u)z=0 = 0, (v)z=0 = 0 ，得 z y w z v x w u = − = − , 于是应变分量用 表示为: z y w y v z x w x u y x 2 2 2 2 = − = = − = z x y w x v y u xy = − + = 2 2 w
Under small deformation, because of weeny bending, the curvature of stretch flexural plane along the coordinate direction can approximatively be denoted by bending w o-w k=一 o-w k=-2 oy Thus the strain components can also be written as 人z kz 人.z 7
17 Under small deformation, because of weeny bending, the curvature of stretch flexural plane along the coordinate direction can approximatively be denoted by bending : w x y w k y w k x w k xy y x = − = − = − 2 2 2 2 2 2 Thus the strain components can also be written as: k z k z k z xy xy y y x x = = =
薄城曲 小变形下,由于挠度是微小的,弹性曲面在坐标方向的 曲率可近似地用挠度表示为: =-2 Oo) 所以应变分量又可写成 人z -kz =人.z 18
18 小变形下，由于挠度是微小的，弹性曲面在坐标方向的 曲率可近似地用挠度 w 表示为: x y w k y w k x w k xy y x = − = − = − 2 2 2 2 2 2 所以应变分量又可写成 k z k z k z xy xy y y x x = = =
(2) Physical Functions gnoring the strain caused by 0, physical functions become Lo E ELy AOx 2(1+ D E xy Express the stress components with strain components, we have E E、+ALE 1- E O.= 十E E 2(1+) 19
19 （2）Physical Functions Ignoring the strain caused by , physical functions become: z ( ) xy xy y y x x x y E E E + = = − = − 2 1 1 1 Express the stress components with strain components,we have: ( ) xy xy y y x x x y E E E + = + − = + − = 2 1 1 1 2 2
薄城曲 (2)物理方程 不计σ所引起的应变,物理方程为: :-Ao,] E O E 2(1+L E 把应力分量用应变分量表示,得: E[+,] 1-l E t ua E t =vxy 20
20 （2）物理方程 不计 z 所引起的应变，物理方程为： ( ) xy xy y y x x x y E E E + = = − = − 2 1 1 1 把应力分量用应变分量表示，得： ( ) xy xy y y x x x y E E E + = + − = + − = 2 1 1 1 2 2