Stress Determination in thin wall cylinder

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Discussion Overview

The discussion revolves around calculating the stress in the wall of a thin-walled cylinder storing water, particularly how the pressure at a given depth affects this stress. Participants explore the applicability of the thin-walled pressure vessel stress formula in different orientations of the cylinder and consider additional factors such as frictional forces.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant inquires about using the formula stress = pd/2t for calculating stress at a certain depth in a vertical thin-walled cylinder storing water.
  • Another participant confirms that the formula is applicable for a vertical axis storage tank with still water.
  • A follow-up question asks whether the same formula can be applied if the cylinder is inclined and how to incorporate frictional forces into the stress calculations.
  • One participant expresses confusion regarding the mention of frictional forces and requests more detail or a diagram to clarify the situation.
  • A participant clarifies that they are analyzing a silo structure with pressures and frictional forces, suggesting that the cylinder with water was a simplified example.
  • A later reply acknowledges that while the formula is a good approximation, it may not be exact due to the variation of stress and hoop strain with depth.

Areas of Agreement / Disagreement

Participants generally agree on the applicability of the thin-walled pressure vessel stress formula for vertical cylinders, but there is uncertainty regarding its application to inclined cylinders and the role of frictional forces. The discussion remains unresolved on these points.

Contextual Notes

Limitations include the assumption that the cylinder is thin-walled and the potential variation of stress with depth, which may affect the accuracy of the formula used. The discussion also highlights the need for clarity on the influence of frictional forces in the analysis.

Who May Find This Useful

Individuals interested in structural analysis, particularly in the context of pressure vessels, silos, and the effects of orientation and friction on stress calculations.

scootypuffsnr
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hi, i was wondering if a thin walled cylinder was storing water, where the pressure is dependent on the depth of water, how would you calculate the stress in the wall at some depth,
eg are you allowed to use the thin walled pressure vessel stress formula: stress = pd/2t and use the water pressure at that depth?

Thank you
 
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Yes that's ok for a vertical axis storage tank holding still water .
 
Last edited:
thank you so much for the reply,
what do you mean for the vertical axis? if the cylinder was inclined at the bottom of the cylinder would you not be able to apply the same equation
and also do you know how would you include frictional forces if it was acting at the same time in the stress calculations
 
I don't understand where your frictional forces have come from .

Describe what you are doing in more detail and/or send a diagram ?
 
im actually analyzing a silo structure storing bulk material to analyze the stress concentrations near the bolt holes so it would have pressures and frictional forces on the walls but just thought cylinder with water would be easier to describe
 
scootypuffsnr said:
hi, i was wondering if a thin walled cylinder was storing water, where the pressure is dependent on the depth of water, how would you calculate the stress in the wall at some depth,
eg are you allowed to use the thin walled pressure vessel stress formula: stress = pd/2t and use the water pressure at that depth?

Thank you
This would be a very good approximation but it would not be exact because of the variation of stress (and hoop strain) with depth.

Chet
 

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