A tubular column supports a mass as shown in the diagram below. A
strain gauge is placed transversely on the outside diameter of the bar to
act as a load measuring device.
The column has an outside diameter of 50 mm and an inside diameter of
40 mm. The modulus of elasticity of the tube material is 250 GN m–2 and
the poison’s ratio is 0.33.
Q. Sketch a graph of the expected strain against the applied load, for a
load range from 0 to 500 kg. Make load the horizontal axis on the
graph and strain the vertical axis.
Force,N = M.G
Area,A = ∏/4 . (Do2 - Di2) = ∏/4 (0.05m2) - (0.04m2) = 7.0685834 x10-4 m2
Normal Stress, σ = F / A
Normal Strain, ε = deformation in length / Original Length = l - l0 / l0
Young's Modulus, E = σ / ε = 250 GN m–2 = 250x10-9 N m-2
ε = σ / E
Poisson's Ration, V = 0.33
Transversal Strain, εt = -νε
The Attempt at a Solution
Calculate Force, N, for range 0kg to 500kg using using F=MG
Calculate Normal Stress for the range 0kg to 500kg using σ = F/A
Calculate Normal Strain for the range 0kg to 500kg using ε = σ / E
Calculate Transverse Strain for the range 0kg to 500kg using εt = -νε
Plot a graph using Transverse Strain εt Vs Force, N
Does this look anywhere near correct?