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stress and strain calculation?
hi, please help me solve this:
A composite bar is 350mm long and consists of a copper tube butt-welded to the end of a steel bar. The copper tube dimensions are: 30mm dia x 10mm bore dia x 200mm long, and the steel bar is 30mm dia x 150mm long. If the composite bar supports an axial force of 4kN, determine:
a) the stresses in the steel and copper
b) the change in length of the composite bar (Esteel = 200GN/m2, Ecopper = 120GN/m2)
It's so confusing..thanks!!!!!!!!!
1 Answer
- BrambleLv 79 years agoFavorite Answer
a) Stress in copper = force /area = 4000 ͯ 4 ͯ 10^6/[π.(30²-10²)] = 6.366 ͯ 10^6 N/m²
Stress in steel = 4000 ͯ 4 ͯ 10^6/[π ͯ 30²] = 5.659 ͯ 10^6 N/m²
b) change in length ∆L= stress ͯ original length / E
For copper ∆Lc = 6.366 ͯ 10^6 ͯ 0.2 / (120 ͯ 10^9) = 10.610 ͯ 10^-6 m
For steel ∆Ls = 5.659 ͯ 10^6 ͯ 0.15/(200 ͯ 10^9) = 4.244 ͯ 10^-6 m
Total change in length = 10.610 + 4.244 = 14.85 μm.
