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).

On the Effectiveness of Composites for Repair of Pipelines Under Various Combined Loading Conditions: A Computational Approach Using the Cohesive Zone Method

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Shahin Shadlou ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Cohesive Zone ◽  
Loading Condition ◽  
Bending Moment ◽  
Combined Loading ◽  
Loading Conditions ◽  
Original Design ◽  
Zone Method ◽  
Noticeable Effect

ASTM PCC-2 standard provides a series of equations for establishing the composite repair's thickness required for bringing the capacity of dented/damaged pipes, to their original design state. However, the accuracy of the equations' predictions for pipes subjected to various combined loadings has not been fully explored. Moreover, the influence of the state of a pipe/composite wrap (CW) interface (i.e., whether perfectly intact or not intact), in reference to the predictions of the ASTM equations, has not been studied either. In consideration of the above-mentioned issues, a comprehensive finite-element (FE) study is conducted, using the cohesive zone methodology (CZM) to simulate the response of pipes repaired with composite wraps, under single and various combined loading conditions. Moreover, the influence of perfect (or tied) and imperfect (unintact) pipe/CW interface on the load-bearing capacity of repaired pipes is systematically investigated. Finally, the effects of composite repairs' thickness and length on their efficacy are also investigated. The results show that, although the pipe/CW interface state does not have any noticeable effect when the pipe is subjected to a combined loading state of bending moment and internal pressure, it plays a crucial role when the pipe is under a combined internal pressure and uniaxial loading condition. Furthermore, the predicted values calculated according to the ASME standard are compared with the finite-element results, demonstrating that ASTM-based predictions do not provide accurate results when a repaired pipe is subjected to an axial loading condition.

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.

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.

Finite Element Simulation of a Strong-Post W-Beam Guardrail System

SIMULATION ◽  
2002 ◽  
Vol 78 (10) ◽  
pp. 587-599 ◽  
Author(s):  
Ali O. Atahan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Full Scale ◽  
Nonlinear Finite Element ◽  
Crash Test ◽  
Original Design ◽  
Dynamic Interactions ◽  
Crash Testing ◽  
Element Simulation ◽  
Test Requirements

Computer simulation of vehicle collisions has improved significantly over the past decade. With advances in computer technology, nonlinear finite element codes, and material models, full-scale simulation of such complex dynamic interactions is becoming ever more possible. In this study, an explicit three-dimensional nonlinear finite element code, LS-DYNA, is used to demonstrate the capabilities of computer simulations to supplement full-scale crash testing. After a failed crash test on a strong-post guardrail system, LS-DYNA is used to simulate the system, determine the potential problems with the design, and develop an improved system that has the potential to satisfy current crash test requirements. After accurately simulating the response behavior of the full-scale crash test, a second simulation study is performed on the system with improved details. Simulation results indicate that the system performs much better compared to the original design.

Advanced Techniques for Establishing Long-Term Performance of Composite Repair Systems

2014 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
The United States ◽  
Operating Conditions ◽  
Repair System ◽  
Composite Repair ◽  
Design Life ◽  
Repair Systems ◽  
Long Term Performance ◽  
Term Performance ◽  
Composite Repairs

Although composite materials are used to repair and reinforce a variety of anomalies in high pressure transmission gas and liquid pipelines, there continues to be widespread debate regarding what constitutes a long-term composite repair. The United States regulations require that composite repairs must be able to permanently restore the serviceability of the repaired pipeline, while in contrast the Canadian regulations take a more prescriptive approach by integrating the ASME PCC-2 and ISO 24817 composite repair standards along with a requirement for establishing a 50-year design life. In this paper the author provides a framework for what should be considered in qualifying a composite repair system for long-term performance by focusing on the critical technical aspects associated with a sound composite repair. The presentation includes a discussion on establishing an appropriate composite design stress using the existing standards, using full-scale testing to ensure that stresses in the repair do not exceed the designated composite design stresses, and guidance for operators in how to properly integrate their pipeline operating conditions to establish a design life. By implementing the recommendations presented in this paper, operators will be equipped with a resource for objectively evaluating the composite repair systems used to repair their pipeline systems.

Validation of Sleeve Weld Integrity and Workmanship Level Development

2006 ◽  
Author(s):  
Robert Lazor ◽  
Brock Bolton ◽  
Aaron Dinovitzer
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Full Scale ◽  
Loading Conditions ◽  
Element Analysis ◽  
Service Failures ◽  
Applied Loading ◽  
Fea Modeling ◽  
Field And Laboratory Conditions ◽  
Scale Data

Full encirclement repair sleeves with fillet-welded ends are often used as permanent repairs on pipelines to reinforce areas with defects, such as cracks or corrosion. In-service failures have occurred at reinforcing sleeves as a result of defects associated with the sleeve welds, such as hydrogen-induced cracks and undercut at the fillet welds, inadequate weld size, and sleeve longitudinal seam ruptures. This work was undertaken to support the development of tools for sleeve design and for conducting an engineering assessment to determine the tolerable dimensions of flaw indications at full encirclement repair sleeves. In particular, the project was intended to validate the stresses estimated using finite element analysis (FEA) models against actual in-service loading conditions experienced at reinforcing sleeves. The experimental work focused on the collection of full-scale experimental data describing pipe and sleeve strains for the following field and laboratory conditions: • Strains induced by sleeve welding, • Strains induced by pressurization of the sleeved pipe, • Strains induced by pressurization of the sleeved pipe and the annulus between the pipe and sleeve. Finite element models of the field and laboratory sleeved pipe segments were developed and subjected to the same applied loading conditions as the full-scale sleeved pipe segments. Comparisons of the measured strains against those estimated using FEA were completed to determine the ability of the models to predict the behaviour of the sleeved pipe segments. Comparisons were made to illustrate the relative strain levels and deformation trends, the accuracies of the strain predictions and trends in changes with pressure, the differences in behaviours between tight and loose fitting sleeves, and the effects of pressurizing the annulus between the pipe wall and sleeve. The analysis of the field data and FEA modeling predictions led to several conclusions regarding to use of numerical models for predicting sleeved pipe behaviour and weld flaw acceptance: • FEA results demonstrated behaviours that were consistent with full scale data, • Trends in the FEA predicted strains agreed with the full-scale data, • FEA models describing the effects of gaps between the pipe and sleeve and annulus pressurization agreed with field experience and engineering judgment, • Evaluation of the significance of root and toe flaws can be completed by extending the models validated in this work.

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.

Full-Scale Elevated Temperature Testing of Composite Repairs in Bending and Compression

2016 ◽  
Author(s):  
Colton Sheets ◽  
Robert Rettew ◽  
Chris Alexander ◽  
Tanya Axenova
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Water Immersion ◽  
Full Scale ◽  
Composite Repair ◽  
In Situ Conditions ◽  
Depth Analysis ◽  
Repair Systems ◽  
Full Scale Testing

The increasing use of composite repair systems in critical and complex applications has brought greater scrutiny to their design and performance. This has been especially true in high-temperature, immersed environment applications where ambient temperature test results with industry standard de-rating factors are all that is available for design. Since this approach does not always adequately capture environmental effects or the performance of composite systems at elevated temperatures, it is beneficial to perform full-scale testing which accurately replicates the in-situ application. In order to accomplish this, a full-scale testing program was developed that subjected multiple composite repair systems to internal and external loads at temperatures up to 120 °C with and without water immersion. This program involved the reinforcement of 12.75-inch × 0.375-inch pipe samples that had simulated corrosion defects. Full-scale load and pressure testing was conducted to simulate the long-term performance of the composite repair systems in the environmental conditions of the application. A strain based performance threshold of 0.4% strain at 120 °C and 100% SMYS was used to develop a competitive program that ranked the participating systems and reduced the number of acceptable repairs from six down to three. This approach increased the efficiency of the full-scale testing and allowed for more in-depth analysis of the top-performing systems. The results of the full-scale testing of six composite repair systems at elevated temperature allowed for a quantitative measure of their effectiveness under in-situ conditions. Several of the systems were shown to provide inadequate reinforcement under these conditions; however, it was also observed that appropriately designed and installed systems are capable of meeting the intense demands of elevated temperature, harsh-service conditions.

Efficiency Assessment of the Composite Materials Repair Systems Intended for Corrosion Damaged Pipelines

2019 ◽  
Author(s):  
Andrei Dumitrescu ◽  
Alin Diniţă
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Finite Elements ◽  
Numerical Models ◽  
Plastic Region ◽  
Research Work ◽  
Repair System ◽  
Composite Repair ◽  
Erosion Processes ◽  
Repair Systems

Abstract This paper presents the results of the research work carried out by the authors in order to evaluate the efficiency of the composite material wraps/sleeves (made of a polymeric matrix and reinforcing fabric) used to repair steel pipelines carrying hydrocarbons upon which local metal loss defects (generated by corrosion and/or erosion processes) have been detected. The pipeline repair technologies consisting of the application of composite material wraps are perceived as being advantageous alternative solutions for substituting the conventional technologies, which require welding operations to be performed in the pipe areas with defects. The efficiency of the composite repair systems has been investigated by assessing the reinforcement effects (the restoration level of the damaged pipe mechanical strength) generated by the applied composite wraps as a function of their geometry and mechanical properties. To that purpose, numerical models based on finite elements have been developed and certified by comparing them with the results of several experimental programs previously performed by the authors. Finite elements simulations have also been conducted in the plastic region, taking into account material non-linearity. The calculation methods proposed in literature (among which a method previously developed by the authors) to define the composite wrap dimensions (thickness and length) for a given pipe have also been investigated and compared to our numerical results in order to select the most adequate solution for the design of the composite repair system. The optimal values for the mechanical properties of the composite material used by the repair system have also been defined.

Cathodic Disbondment Testing Comparison of Carbon Fiber, Fiberglass, and Hybrid Composite Repair Systems for Pipelines

2012 ◽  
Author(s):  
Matthew A. Green ◽  
Larry Deaton ◽  
Christopher J. Lazzara
Keyword(s):  
Cathodic Protection ◽  
Repair System ◽  
Fiber Types ◽  
Preventative Measure ◽  
Composite Repair ◽  
Protection Systems ◽  
Repair Systems ◽  
Cathodic Protection System ◽  
Internal Pressures ◽  
The Impact

Composite repair systems are being successfully and heavily utilized for the repair of a wide variety of pipeline systems operating at high internal pressures worldwide. Many of these pipelines employ cathodic protection systems as a preventative measure of insuring that the pipeline does not corrode. Even with advanced cathodic protection systems, there are still times that a pipeline may become damaged or corroded and composite repair systems are a popular choice. In order to qualify a composite repair system for use on a cathodically protected pipeline, the repair system must undergo specific testing to insure that there will be no issues of disbondment of the composite due to the cathodic protection system. This paper discusses the testing of composite repair systems with varying fiber types, resins, and installation methods. Results have been gathered for several repair system options and indicate that there is variance in the results depending on the above mentioned variables. The results of each of these systems and the impact of the fibers utilized will be discussed and conclusions made as to the effect of cathodic protection on each.

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