Engineering Statics project involving shear & moment diagram of a control arm

AI Thread Summary
The discussion focuses on analyzing the internal loads, specifically shear and moment diagrams, for a bent control arm in a statics project. The user expresses confusion about how to approach the problem since the control arm does not consist of straight members. They seek clarification on whether creating separate shear and moment diagrams for two sections of the control arm would yield the same results. Responses indicate that this method is valid, and the analysis can be conducted as if the sections were aligned. The conversation emphasizes the importance of accurately considering the reaction forces at the pivot in the analysis.
mhrob24
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Homework Statement
Determine internal loads (shear and moment) of the control arm and draw the corresponding diagrams.
Relevant Equations
M = Fd = 0
Fy = 0
Part of a project I am working on (part #3…see description below) is asking us to find the internal loads (shear and moment) and draw the corresponding shear/moment diagrams of the control arm shown below. It’s a little tricky to me, because all of the members associated with these type of problems are normally straight….this travels along the x and y (it’s bent…)

The FBD I drew below shows how I THINK this should be sectioned in order to create the moment and shear diagram, but I’m really not sure. The moments do cancel when you reach the end of that member along the x-axis, so it seems like this should be accurate. Any insight would be beneficial. Thank you!
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You can do your analysis like if sections a and b were aligned, there is no difference regarding internal moments and shear loads.
The direction of the reaction force vector at the pivot must consider the directions of forces P and F, though.
 
Lnewqban said:
You can do your analysis like if sections a and b were aligned, there is no difference regarding internal moments and shear loads.
The direction of the reaction force vector at the pivot must consider the directions of forces P and F, though.

Thank you. You help me out a lot with questions on here. I appreciate it.

Let me ask you this: so if you look at the FBD I drew on the red pad where I made my cut through section A along the x axis…..if I made the shear/moment diagram with that, and then made another FBD but this time, I had the section B along the x-axis and made a second moment diagram for that section, would that be the same thing? I don’t see how it couldn’t be, but I want to see what you think, because that was my initial intent….just make 2 moment diagrams from each “arm” of the control arm.
 
mhrob24 said:
Thank you. You help me out a lot with questions on here. I appreciate it.

Let me ask you this: so if you look at the FBD I drew on the red pad where I made my cut through section A along the x axis…..if I made the shear/moment diagram with that, and then made another FBD but this time, I had the section B along the x-axis and made a second moment diagram for that section, would that be the same thing? I don’t see how it couldn’t be, but I want to see what you think, because that was my initial intent….just make 2 moment diagrams from each “arm” of the control arm.
That would be perfectly fine.

Take a look at the last examples of this link:
https://eng.libretexts.org/Bookshel...ibuted_Load_Shearing_Force_and_Bending_Moment

You are welcome. :smile:
 
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