This JIP was formed to investigate the recent increase in early vibration fatigue failures to welded connections in thin-walled piping on offshore installations. The project included data collection, fatigue testing, and formulation of design guidelines. Current design procedures for offshore piping considered static stress levels, and sometimes, low frequency resonance modes. New materials used in piping made these design criteria obsolete. Increasingly, thin walled piping, made of new materials such as duplex* or stainless steels, was being installed offshore. This piping not only weighed less (a very important consideration for floating production facilities), but also permitted higher flow rates and has increased resistance to erosion.
* Duplex steels are a family of stainless steels. These steels have a high chromium content that makes them suitable for applications requiring high corrosion resistance and high stress corrosion cracking resistance.
MTD completed an assessment of the problem and developed a set of guidelines. The guidelines are split into four sections. The first section outlines the different vibration mechanisms and their effect on piping systems and small bore pipe connections. The second section is the methodology to assess the likelihood of failure of a piping system and the third section outlines possible design solutions or best practices. The fourth section outlines a simple way of determining if a small bore connections is susceptible to vibration by the use of standard vibration measurement tools and a series of simple nomograms.
MMS has received an electronic copy of the developed guidelines. These guidelines may be purchased from the Marine Technology Directorate (MTD).
The project was completed in 2000.
Since MMS co-funded this study along with multiple participants, the information generated remains proprietary. However, you may be available for purchase the final reports and other information by contacting the contractor, Marine Technology Directorate, Limited (MTD). At the time of this study was funded in 1998, MTD's contact information was:
Marine Technology Directorate, Limited (MTD)
19 Buckingham Street
London WCIN 6EF
Tel: 44 (0) 171 321 0674
During the study, MTD was integrated into the Centre for Marine Petroleum Technology (CMPT) and operated through a Management Services Agreement. CMPT's contact information at the time of study was:
Centre for Marine Petroleum Technology (CMPT)
Offshore Technology Park
Aberdeen, AB23 8GX UK
Tel: 44 (0) 1224 706600
e-mail: cmpt@cmpt.co.uk
web: www.cmpt.co.uk