Cantilever statically indeterminate beam with point load

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Discussion Overview

The discussion revolves around deriving the deflection equation for a statically indeterminate cantilever beam subjected to a point load. Participants are exploring boundary conditions and integration methods to arrive at the correct equation, with some seeking clarification on the application of these conditions.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant requests assistance in deriving the deflection equation due to difficulties with boundary conditions.
  • Another participant states that at the built-in end of the beam, both the deflection and slope are zero, while at the propped end, only the deflection is zero.
  • A subsequent reply confirms the boundary conditions, emphasizing that at the propped end, the deflection is zero, not the slope.
  • A participant mentions attempting to use the equation M=EI d²y/dx² with the boundary conditions but encountered issues leading to a result of zero instead of the expected equation.
  • Another participant requests to see the calculations to better understand the issue rather than starting from scratch.
  • A later reply includes an apology for a delayed response and provides part of the calculations in an attachment for review.

Areas of Agreement / Disagreement

Participants generally agree on the boundary conditions for the beam, but there is uncertainty regarding the application of these conditions in deriving the deflection equation, as one participant's calculations did not yield the expected results.

Contextual Notes

The discussion includes limitations related to the clarity of the calculations provided and the potential need for further elaboration on the integration method used.

Who May Find This Useful

This discussion may be useful for engineering students or professionals dealing with statically indeterminate beams, particularly those seeking to understand boundary conditions and deflection calculations.

sara291
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hi
please if anyone can tell me how i can get the following equation (attachments) of deflection for statically indeterminate cantilever beam with point load (attachments). I'm not an engineering student and having difficulty in coming up with boundary conditions.
looking for help. thanks
 

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At the built-in end, the deflection and slope of the beam are both equal to zero. At the propped end, only the deflection is equal to zero.
 
thank you SteamKing. it means at clamped end y(x) & dy/dx = 0 and propped end only dy/dx=o.
 
sara291 said:
thank you SteamKing. it means at clamped end y(x) & dy/dx = 0 and propped end only dy/dx=o.

You got it half right. At the propped end, the deflection y = 0, not the slope dy/dx, as can be seen by inspection of the figure.
 
i tried these condition to find the deflection equation (eq image in thumbnail) using eq M=EI d^2y/dx^2, by integration method. but when i find the constants of integration by applying these BC and put their values i got zero instead of above equation. please help!
 

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Can you post your calculations? It might be easier than trying to go through the whole exercise from scratch.
 
thank you SteamKing, and sorry for late reply, part of my calculation is in attachment. i hope you understand my writing...
 

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