Drag And Inertia Coefficients For Partially-Buried Offshore Pipelines

Abstract Considering the vast number of articles that have been published during the last 150 years related to hydrogen embrittlement and the multiple attempts to explain the governing mechanisms, it is evident that hydrogen’s effect on mechanical properties in steel is still a controversial topic. This little atom has even by some authors been referred to as the “little devil”. We do not intend to explore this particular description of hydrogen any further. However, we would like to shed some light on the key technical aspects we believe need to be further scrutinized and understood to ensure that the decision-makers have sufficiently reliable data available to decide whether hydrogen gas can be safely transported in new or existing offshore pipelines at an acceptable cost.

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Monitoring Offshore Pipelines Using Forced Transverse Vibration: Data Analysis

Volume 3A: 15th Biennial Conference on Mechanical Vibration and Noise — Vibration of Nonlinear, Random, and Time-Varying Systems ◽

10.1115/detc1995-0384 ◽

1995 ◽

Author(s):

Hugh E. M. Hunt

Keyword(s):

Fluid Flow ◽

Data Analysis ◽

Transverse Vibration ◽

Vibration Amplitude ◽

Support Condition ◽

Offshore Pipelines ◽

Vibration Data ◽

Wavelet Methods

Abstract Vibration methods are used to identify faults, such as spanning and loss of cover, in long off-shore pipelines. A pipeline ‘pig’, propelled by fluid flow, generates transverse vibration in the pipeline and the measured vibration amplitude reflects the nature of the support condition. Large quantities of vibration data are collected and analysed by Fourier and wavelet methods.

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Evaluation of the Effect of Yield to Tensile (Y/T) Ratio on the Structural Integrity of Offshore Pipeline by Limit State Design Approach

Volume 3: Materials and Joining; Pipeline Automation and Measurement; Risk and Reliability, Parts A and B ◽

10.1115/ipc2006-10124 ◽

2006 ◽

Author(s):

Gianluca Mannucci ◽

Giuliano Malatesta ◽

Giuseppe Demofonti ◽

Marco Tivelli ◽

Hector Quintanilla ◽

...

Keyword(s):

Structural Reliability ◽

Failure Modes ◽

Structural Integrity ◽

Limit State ◽

Minor Effect ◽

Offshore Pipelines ◽

Limit State Design ◽

A Minor ◽

Probabilistic Failure Analysis ◽

Failure Probabilities

Nowadays specifications require strict Yield to Tensile ratio limitation, nevertheless a fully accepted engineering assessment of its influence on pipeline integrity is still lacking. Probabilistic analysis based on structural reliability approach (Limit State Design, LSD) aimed at quantifying the yield to tensile strength ratio (Y/T) influence on failure probabilities of offshore pipelines was made. In particular, Tenaris seamless pipe data were used as input for the probabilistic failure analysis. The LSD approach has been applied to two actual deepwater design cases that have been on purpose selected, and the most relevant failure modes have been considered. Main result of the work is that the quantitative effect of the Y/T ratio on failure probabilities of a deepwater pipeline resulted not so big as expected; it has a minor effect, especially when Y only governs failure modes.

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