Question about beam and moment in mechanic engineering

Click For Summary

Discussion Overview

The discussion revolves around a mechanics engineering problem involving a beam system, specifically focusing on calculating reactions at supporting points and moments at a specified point. The context includes homework-related inquiries and the application of static equilibrium principles.

Discussion Character

  • Homework-related
  • Debate/contested
  • Technical explanation

Main Points Raised

  • The original poster presents calculated reactions and moments but expresses uncertainty about their correctness.
  • One participant questions the use of decimal numbers in the calculations, suggesting that the vertical reactions must sum to the total downward load and that a reactive moment at point A is missing from the free body diagram.
  • Another participant asserts that the problem is statically determinate, referencing the zero bending moment at point B as providing an additional equation.
  • A different viewpoint suggests that the problem is statically indeterminate in the x direction due to constraints on lateral movement.
  • Some participants express doubt about whether the question is accurately illustrating the intended problem.

Areas of Agreement / Disagreement

Participants show disagreement regarding the classification of the problem as statically determinate or indeterminate, and there is uncertainty about the correctness of the original poster's calculations. No consensus is reached on these points.

Contextual Notes

The discussion highlights potential limitations in the problem statement and assumptions regarding the beam system, including the need for axial deflection compatibility equations and the implications of lateral movement constraints.

kai92
Messages
8
Reaction score
0

Homework Statement



The beam AB shown is connected to beam BC.Find the reaction at each supporting point and moment at A.
Question.PNG


Homework Equations


This is the FBD given by the lecturer:
FBD.PNG


The Attempt at a Solution


Actually,I get the answer but not sure correct or not.These are my answer:
y=0.14kN
Ax=0N
Ay=0.07kN
Bx=0.105kN
By=0.07kN
Cx=-0.105kN
Cy=7.93kN

Someone please tell me whether my answer are correct or not.If not,please give me suggestion.Thanks
 
Physics news on Phys.org
I am not sure why you are getting decimal numbers..the vertical load for examople is 16 kN down, so the vert reactions at A and C must add to 16 kN up. And the horiz reactions must add up to 6 kN. The reactive moment at A is missing from the free body diagram. The problem is statically indeterminate..to get the horiz reactions, you have to use axial deflection compatability equations (A will 'hog' most of the horizonatl load.)
 
This is statically determinate, the extra equation coming from the zero bending moment at B. What is the bending moment at B, taking moments to the right of B?
 
pongo38 said:
This is statically determinate, the extra equation coming from the zero bending moment at B. What is the bending moment at B, taking moments to the right of B?
Both ends are restrained from lateral movement, thus, the problem is statically indeterminate in the x direction.
 
Apologies. Jay is right. But I wonder if the question is correctly illustrating what was intended?
 
Yes, I have my doubts also.
 

Similar threads

  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
4
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K