(2)卡氏第二定理求位移 △=∑ FN; aFN EA OF F a 1 Fa 2 2 +×1+2 /-3Fx√2a (-√2) EA 2 EA EA 2 Fa(3 +√2 EA 2(2)卡氏第二定理求位移 = + − − + + = = 2 2 3 2 ( 2) 2 2 2 1 2 2 1 2 2 EA F a EA F a EA F a EA a F F F EA F l Ni i Ni B