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Local stiffness rings for pipes with low ring stiffness
21-12-2020, 04:56 PM, (This post was last modified: 28-08-2021, 03:15 AM by shaswin.)
#1
Local stiffness rings for pipes with low ring stiffness
Is it possible to use this workaround for stiffness pipe which has large ovalisations with stiffness rings, because PLE doesn't allow large wall thicknesses.

Possible workaround:
Normal pipe stiffness body = EI
Normal pipe Young's modulus body = E

Local stiffness larger ring = EI2

Factor stiffer = EI2 / EI

Locat material with new E_new = E x factor EI2 / EI with the same Moment of Inertia.

Will this work?
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21-12-2020, 05:23 PM, (This post was last modified: 21-12-2020, 05:28 PM by Dr. J Foerster.)
#2
RE: Local stiffness rings for pipes with low ring stiffness
Basically, yes... but... as the new stiffness ring is missing "body" (material volume) you get excessive stains and stresses in that material.

What we usually do is to re-shape the stiffness ring. We keep the cross section area (and material properties) identical, but reduce the wall thickness. Therefore, the width of the stiffness ring increases.
This way we get a stiffness ring which is acceptable for the program, and still have reasonable strains and stresses in the material in and around the stiffness ring.

Of course it is also possible to combine both approaches, if the changes in width of the stiffness ring is too great.
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21-12-2020, 05:25 PM, (This post was last modified: 28-08-2021, 03:12 AM by shaswin.)
#3
RE: Local stiffness rings for pipes with low ring stiffness
I was thinking of ignoring those small sections Identifiers in DF6.2. So no strains an stresses are calculated there.
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