Finite Element Modelling of Static and Fatigue Failure of Composite Repair System in Offshore Pipe Risers

2014 ◽  
Vol 875-877 ◽  
pp. 1063-1068 ◽  
Author(s):  
Park Hinn Chan ◽  
Kim Yeow Tshai ◽  
Michael Johnson ◽  
Hui Leng Choo
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Failure Mechanisms ◽  
Repair System ◽  
Fe Model ◽  
Composite Surface ◽  
Composite Repair ◽  
Bending Load ◽  
Static Conditions

The static and cyclic failure mechanisms of offshore pipe riser repaired with a designated laminate orientation of carbon/epoxy (C/E) system were studied. The finite element (FE) model takes into account failure mechanisms of the composite sleeve inter-layer delamination, debonding at the steel riser-composite surface interface, and the maximum permissible strain of the repaired riser. Design conditions of the combined static loads (coupled internal pressure, longitudinal tensile and transverse bending) were determined through a limit state analysis [1,2]. The limiting static bending load that causes catastrophic failure under a coupled internal pressure and tensile loadings was determined through Virtual Crack Closure Technique (VCCT). The effects of cyclic bending, mimicking the typical scenarios experienced in pipe riser exposed to dynamic subsea environment, were evaluated and compared against the static conditions. The low cycle fatigue of the composite repair system (CRS) is simulated using a direct cyclic analysis within a general purpose FE program, where the onset and fatigue delamination/disbonding growth are characterized through the Paris Law.

Design of Pipeline Composite Repairs: From Lab Scale Tests to FEA and Full Scale Testing

2014 ◽  
Author(s):  
Remy Her ◽  
Jacques Renard ◽  
Vincent Gaffard ◽  
Yves Favry ◽  
Paul Wiet
Keyword(s):  
Finite Element ◽  
Full Scale ◽  
Combined Loading ◽  
Material Strength ◽  
Repair System ◽  
Loading Conditions ◽  
Original Design ◽  
Composite Repair ◽  
Repair Systems ◽  
Composite Properties

Composite repair systems are used for many years to restore locally the pipe strength where it has been affected by damage such as wall thickness reduction due to corrosion, dent, lamination or cracks. Composite repair systems are commonly qualified, designed and installed according to ASME PCC2 code or ISO 24817 standard requirements. In both of these codes, the Maximum Allowable Working Pressure (MAWP) of the damaged section must be determined to design the composite repair. To do so, codes such as ASME B31G for example for corrosion, are used. The composite repair systems is designed to “bridge the gap” between the MAWP of the damaged pipe and the original design pressure. The main weakness of available approaches is their applicability to combined loading conditions and various types of defects. The objective of this work is to set-up a “universal” methodology to design the composite repair by finite element calculations with directly taking into consideration the loading conditions and the influence of the defect on pipe strength (whatever its geometry and type). First a program of mechanical tests is defined to allow determining all the composite properties necessary to run the finite elements calculations. It consists in compression and tensile tests in various directions to account for the composite anisotropy and of Arcan tests to determine steel to composite interface behaviors in tension and shear. In parallel, a full scale burst test is performed on a repaired pipe section where a local wall thinning is previously machined. For this test, the composite repair was designed according to ISO 24817. Then, a finite element model integrating damaged pipe and composite repair system is built. It allowed simulating the test, comparing the results with experiments and validating damage models implemented to capture the various possible types of failures. In addition, sensitivity analysis considering composite properties variations evidenced by experiments are run. The composite behavior considered in this study is not time dependent. No degradation of the composite material strength due to ageing is taking into account. The roadmap for the next steps of this work is to clearly identify the ageing mechanisms, to perform tests in relevant conditions and to introduce ageing effects in the design process (and in particular in the composite constitutive laws).

scholarly journals Finite Element Analysis of Composite Repair for Damaged Steel Pipeline

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Jiaqi Chen ◽  
Hao Wang ◽  
Milad Salemi ◽  
Perumalsamy N. Balaguru
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Hoop Stress ◽  
Pipe Wall ◽  
Von Mises Stress ◽  
Repair System ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Von Mises ◽  
Infill Material

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

Numerical Analysis of High Pressure Cold Bend Pipe to Investigate the Behaviour of Tension Side Fracture

2012 ◽  
Author(s):  
Celal Cakiroglu ◽  
Amin Komeili ◽  
Samer Adeeb ◽  
J. J. Roger Cheng ◽  
Millan Sen
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Internal Pressure ◽  
Experimental Studies ◽  
Element Model ◽  
Combined Loading ◽  
Element Analysis ◽  
Bend Pipe ◽  
Bending Load ◽  
Bending Loads

The cold bend pipelines may be affected by the geotechnical movements due to unstable slopes, soil type and seismic activities. An extensive experimental study was conducted by Sen et al. in 2006 to understand the buckling behaviour of cold bend pipes. In their experiments, it was noted that one high pressure X65 pipe specimen failed under axial and bending loads due to pipe body tensile side fracture which occurred after the development of a wrinkle. The behaviour of this cold bend pipe specimen under bending load has been investigated numerically to understand the conditions leading to pipe body tension side fracture following the compression side buckling. Bending load has been applied on a finite element model of the cold bend by increasing the curvature of it according to the experimental studies conducted by Sen [1]. The bending loads have been applied on the model with and without internal pressure. The distribution of the plastic strains and von Mises stresses as well as the load–displacement response of the pipe have been compared for both load cases. In this way the experimental results obtained by Sen [1] have been verified. The visualization of the finite element analysis results showed that pipe body failure at the tension side of the cold bend takes place under equal bending loads only in case of combined loading with internal pressure.

FEM Stress Analysis and Leakage Behavior of Pipe-Socket Threaded Joints Subjected to Bending Moment and Internal Pressure

2020 ◽  
Author(s):  
Satoshi Nagata ◽  
Shinichi Fujita ◽  
Toshiyuki Sawa
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Experimental Tests ◽  
Element Analysis ◽  
Contact Conditions ◽  
Sealing Performance ◽  
Bending Load ◽  
Threaded Joints ◽  
Thread Root

Abstract This paper is a report of the studies on the mechanical behaviors and leakage characteristics of pipe-socket threaded joints subjected to bending moment as well as internal pressure by means of experimental tests and finite element simulations. The paper dealt with the 3/4″ and 3″ joints, and the joints for both sizes have two different combinations of thread types in the pipe and socket, i.e. taper-taper thread combination or taper-parallel one, respectively. Experimental bending leak tests showed that the taper-taper joints could retain internal pressure under bending load up to nearly plastic collapse. The taper-parallel joints, however, could hardly keep internal pressure against bending moment even the sealing tape was applied to enhance the sealing performance. Finite element analysis was carried out to simulate those bending tests, especially to clarify the deformation and the stress distribution in the engaged threads in detail. The analysis demonstrated that the sealing performance of the joints highly depend on the contact conditions not only at the thread crest to thread root but also in between flank surfaces. A complicated leak path across the engaged threads under bending moment was identified by the simulation.

scholarly journals A Novel Method for High Temperature Fatigue Testing of Nickel Superalloy Turbine Blades with Additional NDT Diagnostics

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1392
Author(s):  
Dominik Kukla ◽  
Mateusz Kopec ◽  
Ryszard Sitek ◽  
Aleksander Olejnik ◽  
Stanisław Kachel ◽  
...  
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Fatigue Testing ◽  
Turbine Blades ◽  
Nickel Superalloy ◽  
Fe Model ◽  
Destructive Testing ◽  
High Temperature Fatigue ◽  
Bending Load ◽  
Novel Method

In this paper, a novel method for high temperature fatigue strength assessment of nickel superalloy turbine blades after operation at different times (303 and 473 h) was presented. The studies included destructive testing (fatigue testing at temperature 950 °C under cyclic bending load), non-destructive testing (Fluorescent Penetrant Inspection and Eddy Current method), and finite element modelling. High temperature fatigue tests were performed within load range from 5200 to 6600 N using a special self-designed blade grip attached to the conventional testing machine. The experimental results were compared with the finite element model generated from the ANSYS software. It was found that failure of turbine blades occurred in the area with the highest stress concertation, which was accurately predicted by the finite element (FE) model.

Finite Element Modelling of Composite Repair in Offshore Pipe Riser

2012 ◽  
Vol 557-559 ◽  
pp. 2239-2242 ◽  
Author(s):  
Park Hinn Chan ◽  
Kim Yeow Tshai ◽  
Michael Johnson ◽  
Hui Leng Choo ◽  
Shuguang Li
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Finite Element Modelling ◽  
Input Data ◽  
World Wide ◽  
Composite Repair ◽  
Element Modelling ◽  
Reinforced Composite ◽  
First World

The effects of coupled internal pressure and external tension on corroded offshore pipe riser repaired with a designated laminate orientation of carbon/epoxy (C/E) and E-glass/epoxy (EG/E) fibre reinforced composite (FRC) was evaluated. The steel riser (API 5L X60) was characterised through Ramberg-Osgood model while input data of the composites were extracted from those used as benchmark for analysis in the first world-wide failure exercise (WWFE) [1, 2]. It was found that the C/E composite provides superiority over the EG/E and laminates with a dedicated orientation is capable of enhancing the performance of risers subjected to the coupled loadings.

An Investigation Into the Behaviour of Composite Repaired Pipelines Under Combined Internal Pressure and Bending

2009 ◽  
Author(s):  
Ahmed Shouman ◽  
Farid Taheri
Keyword(s):  
Internal Pressure ◽  
Combined Loading ◽  
Repair System ◽  
Loading Conditions ◽  
Fiber Reinforced ◽  
Defect Region ◽  
Element Analysis ◽  
Composite Repair ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

The repair of corroded pipelines with fiber reinforced composite materials has gained wide acceptance in the oil and gas transportation industry over recent times. It has been integrated into the ASME B31.4 and B31.8 pipeline codes, along with CSA Z662. A considerable amount of experimental research has been conducted on fiber reinforced composite repaired pipelines with external corrosion defects subject to hydrostatic internal pressure. However, the effects of the internal pressure, thermal loads and geotechnical loads create combined loading conditions on the buried pipeline that need to be considered. This paper aims to address the effectiveness of fiber reinforced composite repair systems on externally corroded pipelines under combined internal pressure and bending. For that, finite element analysis is conducted to examine the effects of various loading conditions on the effectiveness of the fiber reinforced composite repair system. Typical conventional commercially available fiber reinforced composite wrap systems are used for this purpose. Three loading conditions are considered on both conventionally repaired and unrepaired pipes subject to internal pressure, pure bending and combined internal pressure and bending. Results show that up to the stage of yielding of the steel in the defect region, the steel elastic stiffness counteracts most of the stress that is induced by the in-service loading conditions. Once the pipe is loaded beyond the yielding point of its material at the defect region, the composite starts to take effect, thus carrying a significant portion of the applied stresses. Essentially, by comparing the burst pressures of repaired pipes against unrepaired pipes, it is shown that the fiber reinforced composite system restores the minimum specified strength of the pipe to its value before the defects were applied. The results presented in the paper are believed to reveal the response of the wraps subject to realistic combined loading conditions that to our knowledge are nonexistent in open literature.

A Multi-Purpose Finite Element Model for Flexible Risers Studies

2014 ◽  
Author(s):  
Fabien Caleyron ◽  
Martin Guiton ◽  
Jean-Marc Leroy ◽  
Timothee Perdrizet ◽  
David Charliac ◽  
...  
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Element Model ◽  
Fe Model ◽  
Flexible Riser ◽  
Lateral Buckling ◽  
Axial Tension ◽  
External Pressures ◽  
Flexible Risers ◽  
Treatment Packages

The paper focuses on a Finite Element (FE) model developed at IFPEN, denominated 3D-Periodic, which is dedicated to flexible riser studies. It takes full advantage of the geometric and loading periodicities to reduce the model length and the CPU cost. The model is developed in a commercial FE software with dedicated pre- and post-treatment packages. The model can represent standard cyclic bending with internal pressure and axial tension as well as external pressures load cases to investigate the risk of lateral buckling of tensile armors or of pipe collapse.

Development of a Carbon-Fiber Composite Repair System for Offshore Risers

2008 ◽  
Author(s):  
Chris Alexander ◽  
Larry Cercone ◽  
James Lockwood
Keyword(s):  
Carbon Fiber ◽  
Internal Pressure ◽  
State Of The Art ◽  
Full Scale ◽  
Repair System ◽  
Management Service ◽  
Composite Repair ◽  
Composite Systems ◽  
Bending Loads ◽  
Offshore Risers

Composite systems are a generally-accepted method for repairing corroded and mechanically-damaged onshore pipelines. The pipeline industry has arrived at this point after more than 15 years of research and investigation. Because the primary method of loading for onshore pipelines is in the circumferential direction due to internal pressure, most composite systems have been designed and developed to provide hoop strength reinforcement. On the other hand, offshore pipes (especially risers), unlike onshore pipelines, can experience significant tension and bending loads. As a result, there is a need to evaluate the current state of the art in terms of assessing the use of composite materials in repairing offshore pipelines and risers. The significance of the body of work presented herein is that this study is the first comprehensive evaluation of a composite repair system designed for the repair of offshore risers using a strain-based design method coupled with full-scale prototype testing. This paper presents findings conducted as part of a joint industry effort involving the Minerals Management Service, the Offshore Technology Research Center at Texas A&M University, Stress Engineering Services, Inc., and several composite repair manufacturers to assess the state of the art using finite element methods and full-scale testing methods. Representative loads for offshore risers were used in the test program that integrated internal pressure, tension, and bending loads. This program is the first of its kind and likely to contribute significantly to the future of offshore riser repairs. The end result of this study was the development of a carbon-fiber repair system that can be easily deployed to provide significant reinforcement for repairing risers. It is anticipated that the findings of this program will foster future investigations involving operators by integrating their insights regarding the need for composite repair based on emerging technology.

Investigation on the Effect of Pulsating Pressure on Tube-Hydroforming Process

2011 ◽  
Vol 473 ◽  
pp. 618-623
Author(s):  
Khalil Khalili ◽  
Seyed Yousef Ahmadi-Brooghani ◽  
Amir Ashrafi
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Element Model ◽  
Fe Model ◽  
Axial Feeding ◽  
Hydroforming Process ◽  
The Finite Element Model ◽  
Good Agreement

Tube hydroforming process is one of the metal forming processes which uses internal pressure and axial feeding simultaneously to form a tube into the die cavity shape. This process has some advantages such as weight reduction, more strength and better integration of produced parts. In this study, T-shape tube hydroforming was analyzed by experimental and finite element methods. In Experimental method the pulsating pressure technique without counterpunch was used; so that the internal pressure was increased up to a maximum, the axial feeding was then stopped. Consequently, the pressure decreased to a minimum. The sequence was repeated until the part formed to its final shape. The finite element model was also established to compare the experimental results with the FE model. It is shown that the pulsating pressure improves the process in terms of maximum protrusion height obtained. Counterpunch was eliminated as being unnecessary. The results of simulation including thickness distribution and protrusion height were compared to the part produced experimentally. The result of modeling is in good agreement with the experiment. The paper describes the methodology and gives the results of both experiment and modeling.

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