Inclined Beam w/ UDL Homework Statement

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Discussion Overview

The discussion revolves around calculating the deflection of a hydraulic cylinder at a specific point (point A) in a system involving an inclined beam subjected to a uniformly distributed load (UDL). Participants explore the geometry of the system, the assumptions made regarding support conditions, and the implications of these assumptions on the deflection calculations.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes the setup involving two hydraulic cylinders and an inclined beam, detailing the UDL acting on the beam and the method used to calculate moments at points A and B.
  • Another participant questions the clarity of the deflection being sought at point A, suggesting that the angle of inclination may affect the load distribution on the beam.
  • A later reply clarifies that point B is the tip of the second hydraulic cylinder and discusses the role of a sliding member on the beam, which maintains the distance between the cylinders.
  • There is a proposal to consider the end condition of the beam as simply supported due to the presence of a sliding member, which may affect the choice of deflection formula used.
  • One participant expresses uncertainty about how the UDL was determined based on test conditions and shifts focus to the bending of the hydraulic cylinder piston rather than the beam itself.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the assumptions regarding the support conditions of the beam or the implications of the angle of inclination on the load distribution. Multiple competing views remain regarding the appropriate approach to calculate deflection.

Contextual Notes

There are unresolved assumptions regarding the nature of the supports and the effects of the angle of inclination on the system's behavior. The discussion highlights the complexity of the setup and the need for clarity in defining the conditions of the hydraulic cylinders and the beam.

MayZ91
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Homework Statement



Hello all,

I am trying to find the deflection of a hydraulic cylinder at point A (refer the attached).
There are two hydraulic cylinders, with certain distance apart. On top of it is a beam that is inclined to the horizontal by 12 degrees. The piston is operated by two different pumps, which facilitates in extending and retracting of the pistons individually. I have captured the length of the piston after the guide in the hydraulic cylinder, as it is firmly fixed.
A UDL of 1.56 N/mm is acting on the beam perpendicular to the horizontal.
Please refer the attached to get the geometry of the system.

Homework Equations


I have calculated the moments at point A and B, by assuming these points as fixed. However, they are all rotary joints.
The reason to assume it to be fixed is to break the system into two sub-systems. One is the beam and other are the pistons.
After finding the moment at A and B from first subsystem, I transfer the moment into second sub system to obtain the deflection at A. (deflection = M(L^2)/(2EI))

The Attempt at a Solution



I have attached the excel sheet, where I have done my calculations.
I have ended up with 0.54mm as the deflection. But, this is by assuming the piston is a cantilever (deflection = M(L^2)/(2EI))
However, it is not a cantilever with a free end. The deflection obtained from FEA is 0.036mm.
Please help.
 

Attachments

  • Calculations.xlsx
    Calculations.xlsx
    130.6 KB · Views: 720
  • Image.PNG
    Image.PNG
    36.3 KB · Views: 1,862
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MayZ91 said:
I am trying to find the deflection of a hydraulic cylinder at point A

The deflection at A due to what? Bending? Isn't A the tip of one of your hydraulic cylinders? You have a given position for A (357.34), so what deflection are you thinking about here?

Is B the tip of the second hydraulic cylinder?

It is a bit flaky to take about a uniformly distributed load on an inclined beam if we have to think in terms of the angle of inclination as variable. If the 12 degree angle is decreased to say 8 deg, the horizontal length of the beam increases. Does the total load on the beam likewise increase, or does something else happen? This seems ill posed!
 
Hello,

Thank you very much for going through the post.

You're right, the tip B is the tip of the second cylinder.
Also, to maintain the distance between the cylinders constant, there is a sliding member on the beam CD at point B.
The actual scenario is this, the two hydraulic cylinders are screwed to 2 load beams respectively, these load beams are oriented in the direction of the paper(X-axis). The beam CD is mounted on top of these two load beams. The load beam on B has the sliding point, on which the beam CD slides when the hydraulic cylinder retracts.

The end condition here is the problem. Although the load beam has the sliding member and the rotary joint, the hydraulic cylinder gets tightly screwed to the load beams. Therefore, it may needs to be considered as simply supported with respect to beam CD(I think!)
If its simply supported, then I have to use the elastic beam deflection formula = M*(L^2)/(27*E*I)
What I am trying to find is the deflection of point A, due to bending in horizontal axis (Y-axis).
 

Attachments

  • Co-ordinate system.PNG
    Co-ordinate system.PNG
    307 bytes · Views: 721
Last edited:
And the UDL is decided based on the test conditions. I do not know how that decision is made.
Also, to make it clear, i am not worried about the load beams or the beam CD. My concern is the bending of the piston of the hyd cylinder.
 
Last edited:

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