7-23 O .+ 2 2/947Ma 5.3MPa 1=94.7MPa,a2=50MPa,O3=5.3MPa =+"G-2)2+(a2-01)(01-a)]129m 第16次作业: 7-24 2/+1s2243MPa 27MPa 1=243MPa,2=0,G3=-927MPa 1=243MPa<[o n2=G1-W(2+03)=266MPa<[al 7-26 n3=01-03=-650-(-900=250MPa=[o] a)=229MPa<[7-23 第 16 次作业： 7-24 7-26 650 ( 900) 250 [ ]  r3 =1 − 3 = − − − = MPa =  ( ) ( ) ( )  229 [ ] 2 1 2 3 1 2 2 3 2  r4 = 1 − 2 +  − +  − = MPa     2 3 3 1 2 2 3 2 1 2 1 2 3 2 2 2 2 min max ( ) ( ) ( ) 12.99 . / 2 1 94.7 , 50 , 5.3 5.3 94.7 ( 40) 2 70 30 2 70 30 2 2 k N m m E v MPa MPa MPa MPa MPa d x x y x y − + − − = + = = = =  + − =      −  + = +         −  + =                     ( ) 26.6 [ ] 24.3 [ ] 24.3 , 0, 9.27 9.27 24.3 15 2 15 2 15 2 2 2 1 2 3 1 1 2 3 2 2 2 2 min max r t r t x x y x y MPa MPa MPa MPa MPa MPa                   = − + =  =  = = = − −  + =      =  +         −  + =   