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paxprobellum
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Homework Statement
Consider a cantilever beam of length L where a force F is applied in compression at the bottom of the beam. (An off-center axial point load.) Determine the stress at the top and bottom of the beam at x=L/2.
Homework Equations
There is both compressive and bending stress in the beam. The compressive stress is -F/A and the bending stress is My/I, where F is the force, A is the cross sectional area, M is the applied bending force, y is the distance to the neutral axis, and I is the second moment of area.
The Attempt at a Solution
Applying this force is the same as a pure bending moment, except you gain additional compressive stress. Thus, at all points in the beam, the stress is:
S = -F/A + My/I
Most of the beam will be in compression, and a smaller part of the beam will be in tension.
My difficulty is determining what M is. In cantilever problems with transverse loads, M = M(x) = F*(L-x). I have a feeling M is not a function of x, but is constant over the whole beam. I think its F*d, where d is the thickness of the beam, but I'm not really sure why this is the case.