§91轴向拉压杆的变形及刚度计算 解 b kN 8IN 5kN 3kN 作出杆的轴力图 m 2 m 1.5m 由4l=4l1=∑ EA (b I的团 =4l1+42+Al 7图(单位kN FNIL+FN2 42+FN343 EA (6×103)01)-(2×103)(2)+(3×103)(1.5) (2×10)(500×10 =65×10m 0.065mmc9-1 ᅀ຿ࣸགئԅέ໹ذރէޙസ
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⬅ i i i i EA F l l l N ∆ = ∆ = 0.065 mm 65 10 m (2 10 )(500 10 ) (6 10 )(1)-(2 10 )(2) (3 10 )(1.5) 6 9 -6 3 3 3 N1 1 N2 2 N3 3 1 2 3 = = × × × × × + × = + + = = + + − EA F l F l F l ∆ l ∆ l ∆ l ∆ l