Determining the support reactions of a frame

Click For Summary

Discussion Overview

The discussion revolves around determining the support reactions at points A and B of a frame structure. Participants are addressing the application of static equilibrium equations to solve for unknown forces and moments in a mechanical context.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant presents a moment equation about point A to find support reactions, noting the presence of four unknowns and only three equations.
  • Another participant suggests considering the other part of the frame that includes support B to increase the number of equations available for solving the problem.
  • A later reply proposes that after taking moments for each side, it may be possible to express Cx in terms of Cy or vice versa to simplify the solution process.
  • Another participant emphasizes the importance of correctly applying sign conventions when solving for Cx and Cy, indicating that the direction of forces must be consistent across the sections of the frame.

Areas of Agreement / Disagreement

Participants generally agree on the need to consider additional equations from the other support to solve the problem, but the specific approach to solving for the unknowns remains a point of discussion.

Contextual Notes

There is an indication of missing assumptions regarding the directions of forces and the specific conditions at the supports, which could affect the solution process.

hobbyenthusia
Messages
3
Reaction score
0
Here is a link to the problem:
http://img62.imageshack.us/img62/374/frameow.jpg"
I am trying to find the support reactions at A and B.
I separated the frame at the hinge(call it C) into two parts and took the moment equation about point A.
This gave me: \SigmaMa = -60(25) - 62.5(12.5) + Cx(25) + Cy(25)
The forces in the y:\Sigma Fy = -62.5 + Cy + Ay
The forces in the x: \Sigma Fx =60 + Ax - Cx

From here I am unsure what to do as I have four unknowns and only three equations.
 
Last edited by a moderator:
Physics news on Phys.org
:smile:Hello hobbyenthusia(st), welcome to these forums!:smile:

Try looking at the other part of the frame that includes the support at B. That should give you a total of 6 equations with a total of 6 unknowns.
 
I completely missed that. Thank you.
After taking the moments for each side is it as simple as solving Cx in terms of Cy or vice versa and finishing it up?
 
Yes, solve for Cx and Cy and the rest will follow. Please watch plus and minus signs! If Cx is assumed or found to act to the left on the left section, it must act to the right on the right section.
 

Similar threads

Replies
4
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 3 ·
Replies
3
Views
4K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 3 ·
Replies
3
Views
7K
Replies
2
Views
7K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
3
Views
1K