Understanding Moment in Beam: Analysis and Solution | Beam Homework

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Discussion Overview

The discussion revolves around the analysis of bending moments in a beam, specifically addressing the interpretation of a distributed load and the corresponding equations used in the author's method. Participants are attempting to understand the author's approach and clarify their own calculations related to the beam's moment analysis.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion over the author's calculations regarding the moment, suggesting an alternative equation for the moment analysis.
  • Another participant questions the author's interpretation of the distributed load, asserting that it starts from a specific point and extends to a certain distance.
  • Several participants assert that the author is not wrong, explaining that the bending moment function is designed to reflect the behavior of the distributed load over the specified intervals.
  • Participants repeatedly seek clarification on the reasoning behind specific terms in the moment equation, particularly regarding the application of the distributed load and its effects beyond a certain point.
  • One participant expresses frustration with the lack of speculation allowed in the discussion, emphasizing the importance of adhering to the author's method.

Areas of Agreement / Disagreement

There is no consensus on the interpretation of the author's method or the calculations involved. Multiple competing views remain, with participants both defending the author's approach and questioning specific aspects of the analysis.

Contextual Notes

Participants highlight potential misunderstandings regarding the application of distributed loads and the corresponding moment equations, indicating that assumptions about the load's behavior may not be fully resolved.

chetzread
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Homework Statement


refer to the circled part , i don't understand the author's working .
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Homework Equations

The Attempt at a Solution


I think it should be 450x - 150(4-x) -30092)(x-1) , correct me if I'm wrong . (taking moment about x ) ...
 
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is the author wrong , coz the distributed load start from R1 to 2m from R1 ...
 
chetzread said:
is the author wrong , coz the distributed load start from R1 to 2m from R1 ...
No, the author is not wrong.

The bending moment function EIy" is carefully constructed to show that the distributed load starts at x = 0 and runs to x = 2, after which an equal and opposite distributed load is applied to the beam at x > 2, so that the net distributed load is zero.
 
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SteamKing said:
No, the author is not wrong.

The bending moment function EIy" is carefully constructed to show that the distributed load starts at x = 0 and runs to x = 2, after which an equal and opposite distributed load is applied to the beam at x > 2, so that the net distributed load is zero.
why ? i still don't understand , i can only understand the 450x , why should be -0.5(300)(x^2) +0.5(300)[(x-2)^2 ]
 
SteamKing said:
No, the author is not wrong.

The bending moment function EIy" is carefully constructed to show that the distributed load starts at x = 0 and runs to x = 2, after which an equal and opposite distributed load is applied to the beam at x > 2, so that the net distributed load is zero.
why shouldn't it be 450x - 150(4-x) -300(0.5)(2)(x-1) ??
 
chetzread said:
why shouldn't it be 450x - 150(4-x) -300(0.5)(2)(x-1) ??
I'm not going to speculate on that.

Look, the author has a method of analysis of this beam which he is trying to teach. If you want to develop your own methods, write your own textbook.
 
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SteamKing said:
I'm not going to speculate on that.

Look, the author has a method of analysis of this beam which he is trying to teach. If you want to develop your own methods, write your own textbook.
i don't understand why it is -0.5(300)(x^2) +0.5(300)[(x-2)^2 ] , can you explain ?
 
SteamKing said:
No, the author is not wrong.

The bending moment function EIy" is carefully constructed to show that the distributed load starts at x = 0 and runs to x = 2, after which an equal and opposite distributed load is applied to the beam at x > 2, so that the net distributed load is zero.
why it's 0.5(300)(x^2) ? the 300N/m only 'defined ' from R1 to 2m from R1, am i right ? why shouldn't it be 0.5(300)(2)(x-2) instead? as you said , after 2m , net distributed load is zero
 
SteamKing said:
I'm not going to speculate on that.

Look, the author has a method of analysis of this beam which he is trying to teach. If you want to develop your own methods, write your own textbook.
the location of 300n/m is at R1 and extend to 2m from R1, so ,the EIy" should be = 450x-300(2)(x-1) ?
why there's -0.5(300)(x^2) +0.5(300)( (x-2)^2 )?
I'm confused

Or do you mean the 300(X) force still exist at X >2?
 
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