续) 截面形状 面积A 惯性矩 截面系数W 形心距离e p(ab-a1b) Iv=ab-ab) ab) 3 ah-+br BH Bei +ae2-bh 2(aH +br V王HB-b(5 (续) 截面形状 面积A 惯性矩I 截面系数 e I W = 回转半径 A I i = 形心距离e pab 4 p 4 p 3 y 3 x a b I ab I = = 4 p 4 p 2 y 2 x a b W ab W = = 2 2 y x a i b i = = e a e b = = y x p( ) ab - a1b1 ( ) 4 p ( ) 4 p 1 3 1 3 y 3 1 1 3 x I a b a b I ab a b = - = - a a b a b W b ab a b W 4 p( ) 4 p ( ) 1 3 1 3 y 3 1 1 3 x - = - = A I i A I i y y x x = = e a e b = = y x ( ) b e2 h BH + - 3 3 3 2 3 1 x Be ae bh I + - = 2 x x2 1 x x1 e I W e I W = = 3[ ( )] 2 3 3 2 3 1 HB b e h Be ae bh - + + - 2 1 2 2 1 2( ) e H e aH bt aH bt e = - + + =