Internal forces within a structural beam.?

Question

Question for engineers.

I have a question asking me to calculate the maximum stress induced within a loaded beam. The question gives all the relevant information needed for this to be calculated. However it gives a bending moment force AND an axial force. I can easily calculate these separately, however when it comes to giving the overall effect on the beam i have no idea whether to incorporate both of these loading's to give an overall maximum stress, or whether to leave them at max stress due to axial force and max stress due to bending.

In other words I have:

Stress due to bending: Compressive=Tensile= 54x10^6 N/m^2
Stress due to axial force: Tensile= 156x10^3 N/m^2

Can I incorporate these two values into one overall compressive and tensile stress?

Thanks

Answer 1

Yes, these superimpose.

Answer 2

Yes, you can combine them. Just remember that the portion of the beam above the neutral axis will most likely be in compression (given your loading condition and end fixities) and the bottom of the beam will be in tension. So if the beam is also experiencing an axial compressive force, this will add to the stress at the top of the beam and subtract at the bottom of the beam. This is pretty much how a posttensioned member behaves.

Answer 3

You might use shear and bending moment diagrams in any real crisis the place you have been calculating the stresses in a bending member. Examples comprise bridge design and evaluation, the design of a cantilevered help beam, or designing a fishing rod.

Answer 4

The maximum stress is what is asked for. Yes and yes state all maximum values.