On collapse failure analysis of subsea corroded sandwich pipelines under external pressure

2016 ◽  
Author(s):  
Xiao-li Shen ◽  
Sun-ting Yan ◽  
Fei Wang ◽  
Ming Zhang ◽  
Hao Ye ◽  
...  
Keyword(s):  
Failure Analysis ◽  
External Pressure ◽  
Collapse Failure

Flexible Pipe Curved Collapse Resistance Calculation

2009 ◽  
Author(s):  
Laurent Paumier ◽  
Daniel Averbuch ◽  
Antoine Felix-Henry
Keyword(s):  
Failure Modes ◽  
Analytical Calculation ◽  
External Pressure ◽  
Calculation Model ◽  
Third Party ◽  
Flexible Pipe ◽  
The Past ◽  
Curved Pipes ◽  
Pressure Resistance ◽  
Collapse Failure

In the design of flexible pipelines for offshore field developments, the determination of the pipe resistance while subjected to external pressure and bending is very important in deepwater and is now required by the ISO and API standards. One of the critical failure modes being associated with this type of loads is the hydrostatic collapse. The collapse value of flexible pipe is calculated with a model validated with over 200 tests performed on all possible pipe constructions. This model has an analytical basis, and has been established in the past, leading to a fast and straightforward use. In order to address the bent collapse failure mode, Technip and IFP have therefore developed and improved over the past few years an analytical calculation model, based on the collapse model for straight pipes. The purpose of this paper is to present this design methodology and its validation. The modelling principles of the collapse calculation of straight flexible pipes are firstly presented, along with the main hypotheses. The adaptation to the case of curved pipes is detailed in the sequel of the paper. Many types of flexible pipe samples have been tested up to collapse both in straight and curved configurations. The results of these tests have been used to validate this model. In the paper, several tests results will be presented and compared with the calculations. This model is effective, of straightforward use, and has been certified by a third party. It allows Technip to optimize the flexible pipe design in particular for ultra-deep water applications, where external pressure resistance is very important.

Developments in Testing and Manufacture of Thick-Walled Pipe

2017 ◽  
Author(s):  
Alastair Walker ◽  
Jayden Chee ◽  
Peter Roberts
Keyword(s):  
Safety Factor ◽  
Deep Water ◽  
Maximum Level ◽  
External Pressure ◽  
Full Scale ◽  
Test Facility ◽  
Collapse Pressure ◽  
Pipe Joints ◽  
Collapse Failure ◽  
Pipe Joint

Over the past 20 years there has been a considerable development of the capability to design and manufacture thick walled pipe to manufacture pipelines to operate in ultra-deep water. Design guidance is available in DNV OS F101 [1] in which the safety from pressure collapse failure during pipeline installation is determined by the use of a safety factor. The safety factor has been calibrated using the Load and Resistance Factor Design (LRFD) method in comparison with collapse pressure test results available at the time of preparation of DNV guidance. Because of the huge financial implications of loss of a very long pipeline during installation in ultra-deep water it has been the practice further to base the design of such a pipeline on specific pipe joint collapse tests in conjunction with the DNV information. Pressure testing full-scale pipe joints is an expensive undertaking that requires a suitable pressure chamber. Only a few chambers capable of applying pressures corresponding to very deep water are available in the world and transport of the pipes from the pipe mill to a suitable test facility may be very inconvenient and certainly expensive. This paper describes an alternative approach which could provide data that would enable the preparation of a safe approach specific to the pipeline diameter and design water depth. The approach could enable optimisation of the pipe design, particularly the pipe wall thickness. The proposed method is based on replacing costly full scale pipe tests by corresponding tests on ring specimens cut and machined from manufactured pipe joints. The proposal to use ring testing as the basis for design has been included successfully in the design of pipe for a recent ultra-deep water project [2]. The paper describes equipment used to subject the rings to external pressure and reports on tests carried out to validate the correspondence between the ring collapse pressure and that for the pipe joint from which the ring was obtained. Based on results from such tests it is concluded in this paper that ring pressure collapse testing is indeed a valid method to use as the basis for the design pipes in the next stage of ultra-deep water, i.e. increasing the capability to install pipeline in water depths down to 3500m from the current maximum level of 2500m.

scholarly journals Evaluating the Effect of Embedment Depth on Collapse Failure Analysis of Strip Foundation

2021 ◽  
Vol 9 (5A) ◽  
pp. 1-9
Author(s):  
M. M. Nujid ◽  
J. Idrus ◽  
N. F. Bawadi ◽  
A. A. Firoozi
Keyword(s):  
Failure Analysis ◽  
Embedment Depth ◽  
Strip Foundation ◽  
Collapse Failure

Collapse Failure Analysis of Subsea Corroded Pipeline Under Combined External Pressure and Axial Force

2020 ◽  
Author(s):  
Yanfei Chen ◽  
Guoyan He ◽  
Shaohua Dong ◽  
Fuheng Hou ◽  
Shang Ma ◽  
...  
Keyword(s):  
Axial Force ◽  
External Pressure ◽  
Combined Loading ◽  
Engineering Practice ◽  
Regression Equations ◽  
Collapse Pressure ◽  
Corrosion Depth ◽  
Integrity Assessment ◽  
Collapse Failure ◽  
Subsea Pipelines

Abstract The subsea pipelines are usually located in a corrosive external and internal environment. Corrosion presents to be the most common defect type in subsea pipelines, and it is regarded to be one of the main causes of subsea pipeline failure. Due to subsea subsidence, mudslides, and seismic activities, the pipeline is presented under combined external pressure, bending moments and axial force combined loading cases. The accurate determination of the collapse pressure of corroded pipelines under combined loading is important in engineering practice. On the basis of the finite element method, collapse failure of subsea corroded pipelines under combined loads is investigated. The influence of corrosion length, corrosion width, corrosion depth and diameter-thick ratio on the collapse failure pressure is studied. It is observed that corrosion depth has the most significant impact on pipelines’ collapse capacity. Furthermore, regression equations for predicting the collapse pressure of subsea corroded pipelines are proposed based on numerical results. The solution can be referred to in structural integrity assessment of subsea corroded pipelines.

Simplified Finite Element Models to Study the Wet Collapse of Straight and Curved Flexible Pipes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins ◽  
Eduardo Ribeiro Malta ◽  
Rafael Loureiro Tanaka ◽  
Carlos Alberto Ferreira Godinho
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
3D Models ◽  
External Pressure ◽  
Finite Element Models ◽  
Flexible Pipe ◽  
Collapse Pressure ◽  
Flexible Pipes ◽  
Polymeric Layer ◽  
Collapse Failure

When the external sheath of flexible pipes experiences damage, seawater floods the annulus. Then, the external pressure is applied directly on the internal polymeric layer, and the load is transferred to the interlocked carcass, the innermost layer. In this situation, the so-called wet collapse failure of the interlocked carcass can occur. Simplified methodologies to address such a scenario, using restricted three-dimensional (3D) finite element models, are presented in this work. They are compared with full 3D models, studying both straight and curved flexible pipes scenarios. The curvature of the flexible pipe is shown to be important for wet collapse pressure predictions.

On the collapse failure of dented pipes under bending moment and external pressure

2016 ◽  
Author(s):  
Sun-ting Yan ◽  
Xiao-li Shen ◽  
Hao Ye ◽  
Zhan-feng Chen ◽  
Xuan He ◽  
...  
Keyword(s):  
Bending Moment ◽  
External Pressure ◽  
Collapse Failure

Failure Analysis With the Scanning Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 482-483
Author(s):  
John R. Devaney
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Integrated Circuits ◽  
Failure Analysis ◽  
High Reliability ◽  
Military Applications ◽  
Small Structure ◽  
Useful Life ◽  
Insight Into ◽  
Scanning Electron

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.

Sign in / Sign up

Export Citation Format

Share Document