Characterisation of Ring Testing in the Design of Offshore Oil Transportation Systems
Keywords:Ring collapse test, pipe qualification, out of roundness, seal friction, plastic buckling.
The manufacturing procedure qualification tests (MPQT) of offshore pipelines projects has recently started to rely on ring collapse tests, which consist in testing a short section (50 mm) of a full scale joint. This approach is capable of providing valuable insight into the collapse behaviour of offshore pipelines and has practical, financial and logistic benefits.Detailed analytical and numerical work has been carried out in order to understand the collapse mechanisms and the influence of several parameters, like geometry, material strength and seal friction, on the collapse behaviour has been investigated.It is found that the shape of the initial imperfection and the seal friction can both affect the collapse and produce a variation in the value of the collapsing pressure.
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