- #1
Euilibrium of a deformable body
- Context: Undergrad
- Thread starter x850xtpe
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Discussion Overview
The discussion revolves around solving equilibrium problems related to a deformable body, specifically focusing on the equations of static equilibrium, including the sum of forces and moments. Participants explore the challenges of determining unknowns in a statically indeterminate system.
Discussion Character
- Homework-related
- Technical explanation
- Debate/contested
Main Points Raised
- One participant expresses difficulty in solving for unknowns with only two equations: the sum of forces on the y-axis and the sum of moments.
- Another participant clarifies the need to sum forces in both x and y directions and torques, suggesting that all must equal zero for equilibrium.
- A participant explains that the moment causing rotation is akin to torque and notes the absence of forces acting on the x-axis in their specific problem.
- One participant requests to see the work done so far to better understand the problem and emphasizes the importance of accounting for the direction of forces.
- A later reply provides a link to a resource and suggests that the first equation simplifies to a specific expression, prompting a discussion about the relationships between the variables involved.
- Another participant points out that the beam is statically indeterminate, indicating that additional equations beyond static equilibrium are necessary to solve for the reactions.
- One participant acknowledges a previous reply and mentions having completed calculations based on the provided resource.
Areas of Agreement / Disagreement
Participants generally agree on the need for additional equations to solve the problem due to its statically indeterminate nature, but there is no consensus on the specific approach or the relationships between the variables involved.
Contextual Notes
There are limitations in the discussion regarding the assumptions made about the forces and moments, as well as the specific conditions of the problem that may affect the application of equilibrium equations.
- #2
viola.geek
- 13
- 0
Not sure what you mean by "sum of moment = 0," but for equilibrium problems, I know you need to sum the forces in the x and y directions, sum the torques in the x and y directions, and set them equal to zero as you said, since everything is in equilibrium. Solve for your unknowns.
- #3
x850xtpe
- 4
- 0
The moment which is cause the body to rotate, like torque.
Althought I had built the 2 equations, sum of moments = 0, sum of forces acting on y-asix = 0, I still cannot slove these unknows. I had not set the equation sum of forces acting on x axis, it is because no forces action on x-asix in this case. It is particular problem...
Althought I had built the 2 equations, sum of moments = 0, sum of forces acting on y-asix = 0, I still cannot slove these unknows. I had not set the equation sum of forces acting on x axis, it is because no forces action on x-asix in this case. It is particular problem...
- #4
viola.geek
- 13
- 0
Could you post your work on it thus far? That might make it a bit easier to see what you have.
Also, are you accounting for the direction of each? (Such as a force acting downward being negative, while a force acting upwards being positive? Depending on your axes.)
Also, are you accounting for the direction of each? (Such as a force acting downward being negative, while a force acting upwards being positive? Depending on your axes.)
- #5
- #6
viola.geek
- 13
- 0
I did a quick Google search and found this site: http://www.public.iastate.edu/~fanous/ce332/force/cdmoment.html
Perhaps that will be of some help.
Also, what happened to your first equation? It looks like it simplifies to
100 - 3VB + MA + MB = 0
Are MA or MB at all related to VB and VA (or the forces and the distance away from them)? Maybe you can get an expression for VB in terms of MA or MB.
Perhaps that will be of some help.
Also, what happened to your first equation? It looks like it simplifies to
100 - 3VB + MA + MB = 0
Are MA or MB at all related to VB and VA (or the forces and the distance away from them)? Maybe you can get an expression for VB in terms of MA or MB.
- #7
BobbyBear
- 162
- 1
Your beam is statically indeterminate, which means that you cannot obtain the reactions by simply applying the static equilibrium equations (note that you have four unknowns and only two static equilirbrium equations, eg. one moment equation and one force equation in the vertical direction).
You must use elastic equilibrium equations as well to solve.
You must use elastic equilibrium equations as well to solve.
- #8
x850xtpe
- 4
- 0
Thank you for your reply. According to http://www.public.iastate.edu/~fanous/ce332/force/cdmoment.html , I had done the calculation on my question.
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