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1-Newbie

## Mult-layered compound pressure vessel design

I am trying to calculate the stress and deformation of an assembly made of two cylinders with a water filled annulus. The assembly is frozen and the water expands, causing the inner cylinder to shrink, and the outer to expand.

To solve the problem, I am trying to write simultaneous equations: The contact pressure and diameter at the interface is unkown, but is equal at each ice-cylinder interface.

This approach should work, but I am struggling and would be grateful if anyone has any advice or good references or Mathcad calculations for compound, multi-layer, pressure vessel design.

Many thanks,

Sam

5 REPLIES 5
15-Moonstone
(To:SamW)

Hello, Sam,

Your question reminds me of the "shrinking"

You must find the characteristics of your material at low temperature.

Cordially.

Denis

1-Newbie
(To:DenisJaunin)

Thanks Denis,

I know the material properties at the design temperature but it is the stress created from the interference fit at the interface that I am struggling to calculate.

Sam

15-Moonstone
(To:SamW)

Hello, Sam,

I'm sorry, I did not use a good translation from French to English.

I wanted to talk about "frettage" cold.

I enclose some links, but French.

Cordially.

Denis

http://www.raymondnicolet.ch/volume1/Volume_1.pdf
Chapitre 5, page 1.151

1-Newbie
(To:DenisJaunin)

Denis,

Apologies it has taken me so long to reply.

My French is a bit poor but I managed to pick up what you were suggesting auto-frettage seems to be the route to go.

Cheers,

Sam

23-Emerald I
(To:SamW)

Like many problems, you must make the deflections balance. The stress in the inner cylinder, the stress in the outer cylinder, and the deflections must all make sense. The hardest part may be calculating the volume change of the water/ice.

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