W=mm-HoCIra+b+R D=(a+r) 丌 a+r d(a+b+r C 1y2-y)m(2.D=4 a+r 2丌 D atb+r l2=常量 r,=onm lc y2-y1 a+R 2丌 +r d(a+r t1,=a+b+ 2I a+R D(a+R) 1、l2=常量 V2-VI uoll,c 34 0t21=a+R 2兀a+b+RD-(a+b+R) t,=a+6+t a b R t a R c y y D t D t t II y y t D a b R D a R a R c a b R W IMI m = + + = + = - - - × - = - + + - + × + + + = = 2 1 2 1 2 1 1 0 2 2 1 2 0 2 ln( ) 2 ( ) ] ( ) ( ) ln[ 2 p m p m ) ( ) 1 1 ( 2 0 2 2 1 2 1 2 2 34 a b R D a b R II c t a b t a R c y y I I t W f m - + + - + + = = + + = + = - = ¶ ¶ = p m 、 常量 ) ( ) 1 1 ( 2 ) ( ) 1 1 ( 2 0 2 0 2 2 1 2 1 2 1 12 a R D a R II c a R D a R II c t a b t a R c y y I I t W f m - + + + = - - + - + = - = + + = + = - = ¶ ¶ = p m p m 、 常量