Maximizing Bending Moment in Simply Supported Beams: An Experimental Approach

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Discussion Overview

The discussion revolves around the analysis of a simply supported beam, focusing on determining the maximum bending moment, calculating deflections, and verifying results experimentally using strain gauges. Participants engage in a detailed exploration of the theoretical and practical aspects of beam mechanics, including calculations and diagram constructions.

Discussion Character

  • Homework-related
  • Technical explanation
  • Mathematical reasoning
  • Exploratory
  • Debate/contested

Main Points Raised

  • Participants discuss the steps needed to analyze the beam, including setting up free body diagrams and calculating support reactions.
  • Some participants propose methods for constructing shear and bending moment diagrams based on calculated values.
  • There is a discussion about the M/I diagram and its relevance, with some participants explaining its use in calculating deflection when the moment of inertia varies.
  • One participant questions the validity of their bending moment calculations, leading to clarifications about units and the relationship between shear force and bending moment.
  • Participants explore the application of superposition and Macaulay’s Method for calculating deflections due to multiple loads.
  • There is a noted discrepancy in calculated maximum deflection values, prompting discussions about the correct formulas and methods to use.
  • Some participants highlight that the maximum bending moment and maximum deflection do not necessarily occur at the same point along the beam.

Areas of Agreement / Disagreement

Participants generally agree on the methods for calculating bending moments and deflections, but there are disagreements regarding specific calculations and the application of certain formulas. The discussion remains unresolved on some points, particularly concerning the discrepancies in deflection calculations.

Contextual Notes

Participants express uncertainty about the proper formulas to use for specific load cases and the implications of unsymmetrical loading on bending moments and deflections. There are references to external resources for clarification, but no consensus is reached on the best approach to resolve the discrepancies noted.

Who May Find This Useful

This discussion may be useful for students and practitioners in engineering and physics fields, particularly those interested in structural analysis and beam mechanics.

  • #61
Steamking should I be used for the sum of deflections, 5kNm-1 udl load, 20kN or 30kN point loads to determine. What I value for the beam would be required to halve the maximum
deflection of the beam ?
 
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  • #62
Isn't the total deflection the sum of the individual deflections caused by the UDL and the two point loads?

What would happen if you took the formulas for the deflections caused by each of these loads and added them up?

Don't you get [Bunch of Stuff] / EI + [Bunch of Stuff] / EI + [Bunch of Stuff] / EI ?

How does the value of I influence the value of the deflection of the beam?
 
  • #63
Oxon88, how did you do with these questions? Were the answers you provided correct? Seem to be struggling with this and could use some guidamnce...
 

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