Help Needed: Determine Bending Moment at 0.600m from Roller Support

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Discussion Overview

The discussion revolves around determining the bending moment at a specific distance from a roller support using the principles of virtual work. Participants are seeking assistance with engineering statics problems, specifically focusing on bending moments and torque calculations in structural systems.

Discussion Character

  • Homework-related
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant expresses difficulty with a problem involving the calculation of bending moment at a distance of 0.600m from a roller support, providing specific values for force and distance.
  • Another participant presents a different problem involving two hinged bars and asks for help calculating the torque required for equilibrium.
  • A participant suggests a method involving creating a mechanism by adding a hinge at the point of interest and using a displacement sketch to apply the principle of virtual work.
  • There are requests for assistance in solving the problems quickly due to time constraints, with participants offering to share diagrams online for further help.

Areas of Agreement / Disagreement

Participants generally agree on the need for assistance with the problems presented, but there is no consensus on the solutions or methods to be used, as multiple approaches are suggested without resolution.

Contextual Notes

Some participants mention the principles of virtual work and the need for diagrams, indicating that visual representation is crucial for understanding the problems. There is uncertainty regarding the application of these principles in the context of the problems presented.

Who May Find This Useful

Students or individuals studying engineering statics, particularly those struggling with concepts related to bending moments and torque in structural analysis.

laura001
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hey every1... I'm really really stuck on this problem and unless i get it and a few others right I am going to fail my engineering statics course :( Any help would be apreciated so much...


The Question that goes with that diagram I've attatched is:

Determine the bending moment at a distance x from the roller support on the left hand side, using the principles of virtual work.

The values are: F = 2kn, d=2.200m and x=0.600m

thankyou
 

Attachments

  • Q1.jpg
    Q1.jpg
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Engineering news on Phys.org
another I am not sure about:

Each of the two uniform hinged bars have a mass m and length L. Both bars are connected by hinge S and supported as shown. The structure is loaded by a mass of 4m, applied at the hinge S. Gravitational acceleration is g = 9.81m/s2.

m= 15kg
L=5.500m
angle theta= 130 degrees

Calculate the torque Ma (in Nm) required for equilibrium
 

Attachments

  • Q2.jpg
    Q2.jpg
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laura001 said:
hey every1... I'm really really stuck on this problem and unless i get it and a few others right I am going to fail my engineering statics course :( Any help would be apreciated so much...


The Question that goes with that diagram I've attatched is:

Determine the bending moment at a distance x from the roller support on the left hand side, using the principles of virtual work.

The values are: F = 2kn, d=2.200m and x=0.600m

thankyou

The attachment isn't working, but I can give you some directions. If the system has zero degrees of freedom (i.e. it's not a mechanism), you should make it a mechanism by putting a hinge at the point where you need to find the bendig moment (0.6 m). Draw a displacement sketch of that mechanism, so that you make the hinge rotate for a unit angle, and calculate all the displacement on the places of the loads (i.e. the force F). Then use the principle of virtual work: 'The necessary and sufficient condition for the equilibrium of a rigid body is zero virtual work done by all external forces acting on the particle during any virtual displacement consistent with the constraints imposed on the body.' It's a bit stupid to explain this like I just have - in a 'half-blind' manner, but I hope it helps. :smile:

P.S. The bending moment M you need to find acts at the place of the inserted hinge.
 
Last edited:
laura001 said:
hey thanks for the reply! if i put the diagrams on phototube can u maybe work them out please? i'd appreciate it so much, i usually don't do this but i have to have answers by 2moro which isn't long enough for me to learn about principles of virtual work...

Go ahead, I hope I'll be able to help.
 

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