12/2 N=0 ○ gl2 w= 02 q178 l l= q 1 38 12 ∑ NNDl EA 2 EA 2 EA △ 2y2+0)3y I y1+a2y q22l+122/+1 EⅠ(4343122丿8EⅠ q4 4/ 4 h △ 2EA/8E13Al23b1291 l10 900P=1 1 1 l y1 y2 y3 M 2 3 = l y 3 2 1 2 y = l = y 3 8 12 2 2 3 3 = = ql l ql w 2 2 4 1 2 2 3 1 = = = ql l ql w w 8 3 3 12 2 2 3 4 2 4 1 2 2 2 4 =       = + + EI ql l ql l ql l ql EI ( ) 1 1 1 2 2 3 3 D = + + M y y y EI w w w N =1 ↑↑↑↑↑↑↑↑↑↑↑↑ N =0 q l l ql2 /2 ql2 /8 ql ql/2 ql/2 MP ω1 ω2 ω2 B NP=0 900 1 3 9 4 3 4 8 3 2 10 2 1 2 2 12 2 2 4 3 = = = = = D D = l h bh M N l h Al bhl I EI ql EA ql 2 1 2 2 D =  = × × = P N EA ql EA ql l EA N N l