3 Member force system-Could use some input

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Discussion Overview

The discussion revolves around a statics problem involving a three-member force system with an upside-down L-shaped beam. Participants explore the forces acting on the beam, including vertical and horizontal loads, and the implications for analyzing the system's equilibrium and reactions at a fixed support.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant describes the configuration of the beam and the forces acting on it, including a 3 kN force and a 2 kN force applied vertically, and a 4 kN force applied horizontally.
  • The same participant expresses uncertainty about how to handle the 4 kN force in the context of a three-force member problem, questioning whether it creates a force couple.
  • Another participant emphasizes the need for clarity on what specifically needs to be solved in order to provide assistance.
  • A third participant suggests that the problem appears to be isostatic but does not elaborate further.
  • The original poster acknowledges the request for a visual aid and expresses difficulty in providing one, indicating a desire for suggestions on how to include a picture.

Areas of Agreement / Disagreement

Participants have not reached a consensus on how to approach the problem, particularly regarding the treatment of the 4 kN force. There are multiple viewpoints on the necessity of additional information and visual aids for effective discussion.

Contextual Notes

The discussion lacks specific details on the desired outcomes or calculations, and there is an absence of visual representation of the problem, which may limit the clarity of the analysis.

M98Ranger
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I have a simple statics problem that I am trying to solve. The rigid body to be analyzed is an upside down L-shaped beam connected together at the corner by a pin. The object has a height of 4.5 meters vertically, by 3.5 meters in the horizontal. Additionally, the object is secured to the ground by means of a fixed support (cemented into the ground). In the corner of the upside down L connected diagonally is a structural element connected by pin joints at both ends. The lower end of the structural element is connected to the upside down L object 3 meters above the ground. The higher end is connected two meters from the corner of the L.

One 3kn force (straight down) is applied at 1 meter from the corner of the upside-down L-shaped object on the horizontal member. On the same member at the very end (3.5m from the corner) is a 2kn force applied straight down. Lastly there is a given 4kn force applied applied horizontally at a point 3.5 meters above the ground on the vertical member of the upside down L.

PS: I have tried to work it out on my own by combining the 3 and 2kn forces and then summing the moments about the fixed support. And summing the forces in the X and Y. I am not happy with my answers though and would like to know what someone else thinks about it. Additionally I have been reading everything I could on the internet since morning.

PHEW! Here is my question. It seems to me that I have a 3 force member problem here. But I am not sure how to deal with the 4kn force. It seems to me that the 4kn force and the X componant of the force at the corner of the upside down L would make a force couple.

As a three-force member is defined as a rigid body with no force couples, acted upon by a system of forces composed of or reducible to, three forces at three different locations I am not sure what I have here. How do I deal with the 4kn force?

SOLVE...find the reactions at the fixed support (where the beam is cemented into the ground).
 
Last edited:
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In order to solve a problem one needs to know what is to be solved for. You have not supplied this information...:wink:
 
A picture would be nice :smile:, but so far is an isostatic problem.
 
There I edited my original post. So far as a picture... I wish I could, but I don't know how. Any suggestions? I could find a similar picture and try to cut and paste it into a post.
 

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