Beam Design (max allowable force) - Help

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    Beam Design Force
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Discussion Overview

The discussion revolves around calculating the maximum allowable force for a simply supported I-beam under a central load, specifically in the context of beam design for a gantry. Participants explore the necessary calculations and considerations related to bending moments, bending stress, and material properties.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Post 1 presents the parameters of the beam and requests assistance in calculating the maximum allowable force and assessing the safety of using a 2000N load.
  • Post 2 suggests finding the maximum bending moment as a function of the load and calculating the maximum bending stress using the appropriate formula, emphasizing the need for the yield stress of the material.
  • Post 3 expresses confusion regarding the solution provided and clarifies that the inquiry is for a company project rather than a homework assignment.
  • Post 4 proposes an assumption for the tensile yield strength of mild steel and estimates the maximum allowable midspan point load to be 21.0 kN, while also providing a note on unit formatting.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the calculations or the assumptions regarding material properties. There are differing levels of understanding and clarity regarding the technical details, with some participants expressing confusion.

Contextual Notes

There is uncertainty regarding the specific yield stress value for the type of mild steel being used, and the discussion does not resolve how to apply the safety factor in the calculations. Additionally, the assumptions made about the beam's properties and loading conditions are not fully clarified.

Who May Find This Useful

Individuals involved in structural engineering, mechanical design, or those needing to understand beam design principles in practical applications may find this discussion relevant.

its.me.lah
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Homework Statement



Case:

-Simply supported beam with central load. L = 570cm
- I-Beam. Height = 15cm. Base = 15cm. Thickness = 1cm.
- Material = mild steel. Assuming E = 210GPa.
- Safety Factor = 1.5.
- F = 2000N.

With those information i had obtained the I = 16.56x10^6 mm^4.

Now i don't know how to calculate:
- the max allowable force before it fails.
- If F = 2000N, is it safe to use this beam.

Please help.
 
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You will need to find the maximum bending moment in the beam as a function of F, then find the maximum bending stress under that maximum moment, using the maximum bending stress formula, which you should be familiar with. Now you must know the yield stress for the given material, which must be given to you, since such yield stresses depend on the type of mild steel you are using. Apply safety factor appropriately, watch units, and solve for the allowable load F.
 
Dear PhantomJay...i am totally lost with your solution...would you please explain further..

Actually this is not my homework..my company wants to design a gantry and they want me to calculate the maximum allowable force for the beam.

Thanx again..
 
You could assume tensile yield strength, Sty = 235 MPa. Then you could say the maximum allowable midspan point load is F = 21.0 kN.

By the way, its.me.lah, always leave a space between a numeric value and its following unit symbol. E.g., 2000 N, not 2000N. See the international standard for writing units[/color] (ISO 31-0[/color]).
 

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