The bendi ont B is wx gr dx The bending at point d is w+o-dy Ou aw Ov aw Fromy =Andy,=0 we know 0 z Ox Or can be written as ax az After integral by z, and using u)-=0, )-=0 we get 2 Ox au aw Then the strain components 8 2 can be expressed byW as aw 8.= 2 au e Oy ax Oxay 1515 The bending at point B is dx x w w   + The bending at point D is dy y w w   + From and we know  xz = 0  yz = 0 0, = 0   +   =   +   y w z v x w z u Or can be written as y w z v x w z u   = −     = −   , After integral by z, and using ( ) 0, ( ) ， 0 we get 0 0 = = z= z= u v z y w z v x w u   = −   = − , z x y w x v y u xy    = −   +   = 2  2 Then the strain components can be expressed by as z y w y v z x w x u y x 2 2 2 2   = −   =   = −   =   W