Calculating Max Bending Moment: Physics Advice Needed

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SUMMARY

The discussion focuses on calculating the maximum bending moment for a simply supported beam that is 3 meters long, subjected to two point loads: 5 kN at 1 meter and 10 kN at 2 meters. The user initially calculated shear forces and bending moments but received feedback on the importance of precision in calculations and proper unit notation. After recalculating, the maximum bending moment was determined to be +8.334 kN, located 2 meters from point A. The discussion emphasizes the need for accuracy in engineering calculations and the correct use of units.

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  • Understanding of shear force and bending moment diagrams
  • Familiarity with static equilibrium and point loads
  • Knowledge of significant figures in engineering calculations
  • Ability to apply basic structural analysis principles
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  • Study the derivation and application of the bending moment equation for beams
  • Learn how to construct shear force and bending moment diagrams accurately
  • Explore the significance of significant figures in engineering calculations
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Civil engineers, structural engineers, and students studying mechanics of materials who need to understand bending moment calculations and their applications in structural analysis.

charger9198
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Physics advice please?
If a question was to ask, calculate the maximum bending moment

Could I find out the shear force points and graph it, then calculate and plot the bending points and manually find the max by observing the highest peak or is there an equation I should use?

The beam is 3 meters long. Simply supported at either end and carries two point loads, one at 1m (5kn) and the second at 2m (10kn). No u.d.l

Can someone advise me of the best way. Bearing in mind the question says calculate?

For my resistance I get x1 to be 6.7kn and x2 at 8.3kn.

For my shear force diagram I get +6.7 for m1, +1.7 for m2 and -8.3 for m3

Bending diagram I get at m1 to be +6.7, m2 to be +8.4 and m3 to be +0.2

Am I correct so far or have I over complicated things when I could have used an equation?
 
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charger9198: Nice work. However, the unit symbol for kiloNewton is kN, not kn. Lowercase n means nano. Also, always leave a space between a numeric value and its following unit symbol. E.g., 10 kN, not 10kN.

Generally always maintain at least four significant digits throughout all your intermediate calculations, then round only the final answer to three significant digits. E.g., 6.667 kN, not 6.7 kN. Your numbers are too rounded, and this may have caused your final answer to be slightly inaccurate. Also, points are usually labeled with letters (A, B, C, D), so I do not really know what you mean by m1, m2, m3.

From your plot, you can manually see that the maximum bending moment occurs at point C. Therefore, you can compute the maximum bending moment at point C (as I think you already did). Except round it to three significant digits of precision, not two. Also, your moment at point D is currently incorrect.
 
nvn: Many thanks for the advice, i re-calculated accordingly and seemed to get more accurate answers
0
A= +6.667 kN
B= +8.334 kN
c= +0.001 kN

I shall draw the shear force and bending moment diagram inline with the given and show the maximum bending moment to be +8.334 kN 2m from point A
 

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