&LDF 3E N/m2 x2b△n 4 Un=△,=0.05cmU,=△,=0.02mm U,=△=0.05cm U,=△=0.005mm E×100 g+()2+(24)2= △n 5U=E×E N/m2 E=E±U N/m2 E3 _______N/m2 4 _______ 5 ________N/m2 ________N/m2 2 8LDF E d b n = =  UD = 仪 = 0.05cm Ub = 仪 = 0.02mm UL = 仪 = 0.05cm Ud = 仪 = 0.005mm UE = EEE = E = E UE = 2 2 2 2 2 100% ( ) ( ) ( ) (2 ) E E D L n b d E U U U U U U E n D L b d          =  = + + + + = 