bluuebunny/crossref_metadata_2025 huggingface dataset:
A Synthesized Approach to Pressure Reduction for Investigating Mechanical Damage
Authors: Rosenfeld M. J.
Published: April 2011

It is often recommended that the operating pressure of a pipeline be reduced prior to investigating suspected mechanical damage in the field, due to the unknown severity of the damage. The primary question is: knowing only what can be inferred from in-line inspection and the characteristics of the pipeline, what is the appropriate amount of pressure reduction? Secondarily, operators also question whether the same pressure reduction is necessary for all pipelines, e.g. different Location Classes, and all modes of damage, e.g. rock-induced damage as opposed to encroachment damage. Two levels of assessment are provided: a conservative “Level 1” assessment relying on mainly qualitative information and requiring no calculation, and a “Level 2” assessment that is considerably more involved but which could justify a smaller pressure reduction in response to the damage. The choice of assessment level will depend on the information available to the operator, as well as on the degree of conservatism the operator desires to invoke.
Field Test of a Leak Detection System: Planning, Execution and Results
Authors: da Silva Daniel Sampaio , Melo Filho Si´lvio A. , de Farias Mauro Niehues , Pacheco Anderson
Published: April 2011

The OLAPA pipeline (Oleoduto Arauca´ria–Paranagua´) is a 12in diameter pipeline and, with its 97,6 km in length, crosses a mountain region called “Serra do Mar” attaining elevations of about 900m in a dense forest region. Besides that, this pipeline crosses cities, farms, rivers, including a short submerse stretch in the Paranagua´’s bay. An incident in this pipeline could result in severe consequences, especially under the environmental point of view. Therefore, this pipeline was chosen to test the performance of a new leak detector system in Transpetro. The test consists in comparing the theoretical results with practical values of alarm times obtained from a controlled removal of product in an adequate point, in the middle of the pipeline, simulating a real leak. The system chosen to be tested was the LeakWarn system, which is a computational system that uses the mass balance principle with line pack change to analyze the pipeline operational parameters in order to alert when there is a risk of product leak. This test had the objective to evaluate the LDS and help Transpetro’s management team to analyze and decide whether or not to replace its current leak management system, since this new one showed the expected results and was compatible with the excellence level already achieved in the company. The field test was performed in July 7th 2009, through a vent valve far from the ends of the pipeline and it was made in three different conditions: 1) A big leak in the steady state of operation; 2) A small leak also in the steady state of operation; and 3) A big leak in the transient state of operation (immediately after the pump station start up). In order to proceed this test, a multidisciplinary team was assigned and several resources were used such as: Two tank trucks, a specially designed leakage line with control valves, measuring system, flexible hoses, communication systems and emergency equipments. The complete operation was monitored from the Control Center in Transpetro’s Headquarter, Rio de Janeiro. This paper describes the way the tests were performed and presents the results in order to contribute with useful information to be used in any field test for any other leak detection system. It shows how planning were done in order to insure that all operations would be performed according to strict procedures and in a safe way. It also describes the milestones and the work of each team involved in the activity, as well as their constraints and difficulties that had to be overcome during the planning and execution phases, that lasted approximately one year.
Manufacturing of 25mm Heavy-Wall Linepipe Using the High Frequency Induction (HFI) Welding Technique: A Challenge for a Pipe Manufacturer
Authors: Tazedakis Athanasios S. , Voudouris Nikolaos G. , Musslewhite Mike
Published: April 2011

The current thickness limit of the HFI technique is about 20,6mm for grades up to X80. It is mainly governed by the necessary forming load, the coil edge formability and above all the optimisation of the power/heat input requirements on the weld seam area. The availability of hot rolled coils in thicknesses up to 25mm has made possible the exploitation of the HFI limits to such thicknesses. Following the successful industrial HFI welding production of 609,6mm (24″) × 25mm thick wall pipes at the CPW-Thisvi mill, the current paper deals with the development of the process regarding forming, welding, process automation and NDE inspection techniques for thicknesses up to 25mm. The latter made possible the broadening of the HFI process limits, currently for grades up to X60. Details of the technology used are described along with the investigation of the influence of welding and post-weld heat treatment (PWHT) cycles on the microstructure of the welding zone (WZ) and heat affected zone (HAZ) of the hot-strip micro-alloyed high strength low alloyed (HSLA) steel chosen. Mechanical testing of the pipe body and weld seam was used to characterise their performance. The dimensional tolerances of the pipe products are also described. Results of the study showed properties which were uniform and satisfied API 5L requirements. The above research demonstrates that the HFI technique has a clear potential to provide the energy market with lower cost-options for the construction of heavy wall pipes.
In-Line Inspection Performance III: Effect of In-Ditch Errors in Determining ILI Performance
Authors: McNealy Rick , McCann Roger , Van Hook Michael , Stiff Amanda , Kania Richard
Published: April 2011

The performance of in-line inspection tools employed for pipeline integrity assessments has significant impact on the reliability of assessment results and subsequent remediation program. Previous papers by the lead authors established criteria for determining the number of “successful” field validation measurements for establishing whether a tool’s performance should be accepted or rejected and how to assess the tool performance when a claimed performance can be neither rejected nor accepted. This “apparent” validated performance contains both the ILI tool measurement error and the in-ditch measurement error. Determination of the true tool error can have significant impact on the response to ILI feature characterization relating to timing for repairs and justification of re-assessment intervals. Measurement errors, associated with the currently available technologies employed in the field for in-line inspection metal loss validation measurements, are discussed in this paper. The relative effect of variations in validated tool error due to field measurement error on pipeline integrity is discussed within the context of actual in-line assessment case studies.
Field Girth Weld HAZ Toughness Improvement: X80/Grade 550
Authors: Penniston Christopher , Collins Laurie E.
Published: April 2011

Field welding and field weld rework can be a significant cost in the construction of pipelines. Heat affected zone (HAZ) material adjacent to a weld is of particular concern because the base material microstructure has been altered significantly. In instances where Engineering Critical Assessment (ECA) is used for defect acceptance, optimizing and/or improving the base material for field weldability will reduce repair welding rates, which in turn improves project economics. Several alloys of X80/Grade 550 were assessed. All materials were robotically welded to simulate a typical mechanized field weld. Two of the alloys were also welded using a field mechanized welding system. These welds were subjected to tests assessing field weldability. Weldability is a broad term used to summarize various material properties related to the level of conduciveness to welding. For the purposes of this paper, the term field weldability is used to describe the level of HAZ toughness of a material subjected to field welding conditions. Charpy V-notch (CVN) and crack tip opening displacement (CTOD) tests were utilized to assess the toughness of the welded material. Optical microscopy was employed to characterize the HAZ microstructures. In addition, all materials were subjected to HAZ thermal processing in a Gleeble thermo-mechanical simulator. Gleeble dilatometry curves were constructed to characterize phase transformation behavior, and tested materials were used to characterize HAZ microstructures using optical microscopy. Gleeble HAZ CVN specimens were processed in order to assess the toughness of a uniform, idealized HAZ microstructure. It was found that HAZ toughness was better for material chemistries that promote lower phase transformation temperatures. Lower phase transformation temperatures caused the formation of favorable microstructural phases, with finer coarse grain HAZ (CGHAZ) prior austenite grain size, as well as fine packet size. Phase transformation temperature and prior austenite grain size were found to be most dependant on the carbon and carbon equivalent content of the material. The steel containing the lowest amount of carbon displayed the highest phase transformation temperature, coarsest CGHAZ prior austenite grain size, and lowest HAZ toughness, as measured by CTOD and CVN tests.
Project Management Considerations of Pipelines Crossing the Andes
Authors: Pettinger Alfred M. , Montgomery Robert
Published: April 2011

Pipeline operators, contractors and governments face important challenges when planning, designing, constructing and operating pipelines which connect the hydrocarbon reserves in the Amazonian basin with population and shipping centers on the Pacific coast. These pipelines cross portions of the Amazonian rainforest, the mountain rainforest along the eastern flank of the Andes, the Andean plateau, and the rural and urban low lying desert areas along the Pacific coast. The need for these pipelines will continue and offers a tremendous opportunity to promote sustainable economic development. However, there are several challenges in safeguarding the integrity of the pipeline, environment, local population, and socio-economic fabric of the region. Failure to properly address these risks could have significant financial, engineering, environmental and social, or reputational consequences for operators, contractors, financiers and governments. In this context, companies need to understand the specific challenges present and implement an encompassing project and risk management strategy that entails leadership, team work, effective communication and collaboration in a manner that proactively meets anticipated needs and responds to evolving conditions. During design and construction management, engineers and scientists are challenged by geology, topography, limited or no field data, limited access to the right-of-way (RoW), and socio-environmental aspects. Major training efforts are needed for the construction workforce, in a manner applicable to educational and cultural characteristics. Special road safety measures are required and in many instances the right-of-way will be the only means of transporting construction material. Other special logistical challenges are presented by the rich cultural history of the Andes. During operation, special consideration needs to be given to external natural hazards like landslides, soil creep, seismicity, and river scour. Management needs to maintain good communication with all parties affected by the project and proactively promote broad socio-economic development in the project area. The recognition of these specific challenges and upfront investment will facilitate mutually beneficial project advancement and be of particular benefit in instances of anticipatable but uncontrollable events. This paper describes several of these challenges and provides guidance on how to minimize project specific risks and adverse effects to society and environment.
A Limit State Function for Pipelines Containing Long Corrosion Defects
Authors: Chebaro Mohamed R. , Zhou Wenxing
Published: April 2011

Currently, there exist various models that predict the burst capacity of a pipeline containing corrosion defects. Recent studies have indicated that these models tend to be overly conservative for long corrosion defects. This paper, based on a PRCI-sponsored study, aims at minimizing this conservatism through a series of steps. First, different definitions for long corrosion defects prevalent in the literature were examined and compared, and the most suitable criterion was implemented. Next, three existing burst pressure models for general corrosion defects were identified and evaluated: ASME B31G-modified, a model developed at C-FER and a model developed at the University of Waterloo. The suitability of these models for long corrosion defects was assessed using a database of 50 full-scale burst test specimens containing natural long corrosion defects. Finally, based on this evaluation, the most apposite burst pressure prediction model for long corrosion defects was selected and a corresponding model error factor was derived.
Markov Chain Model Helps Predict Pitting Corrosion Depth and Rate in Underground Pipelines
Authors: Caleyo F. , Vela´zquez J. C. , Hallen J. M. , Valor A. , Esquivel-Amezcua A.
Published: April 2011

A continuous-time, non-homogenous pure birth Markov chain serves to model external pitting corrosion in buried pipelines. The analytical solution of Kolmogorov’s forward equations for this type of Markov process gives the transition probability function in a discrete space of pit depths. The transition probability function can be completely identified by making a correlation between the stochastic pit depth mean and the deterministic mean obtained experimentally. Previously reported Monte Carlo simulations have been used for the prediction of the evolution of the pit depth distribution mean value with time for different soil types. The simulated pit depth distributions are used to develop a stochastic model based on Markov chains to predict the progression of pitting corrosion depth and rate distributions from the observed soil properties and pipeline coating characteristics. The proposed model can also be applied to pitting corrosion data from repeated in-line pipeline inspections. Real-life case studies presented in this work show how pipeline inspection and maintenance planning can be improved through the use of the proposed Markovian model for pitting corrosion.
Crystallographic Texture Control Helps Improve Pipeline Steel Resistance to Hydrogen-Induced Cracking
Authors: Venegas V. , Herrera O. , Caleyo F. , Hallen J. M. , Baudin T.
Published: April 2011

Low-carbon steel specimens, all within API (American Petroleum Institute) specifications, were produced following different thermomechanical paths. After austenization, the samples were rolled and recrystallized. The rolling process was carried out using different reduction-in-thickness degrees and finishing temperatures. The investigated steels showed similar microstructural features but differed considerably in their crystallographic textures and grain boundary distributions. After cathodic hydrogen charging, hydrogen-induced cracking (HIC) was detected in the hot-rolled recrystallized steels, whereas the cold and warm-rolled recrystallized steels proved resistant to this damage. Among the investigated specimens, the HIC-stricken show either the strongest {001}ND texture fiber, the smallest fraction of low-angle grain boundaries, or the weakest {111}ND (γ) texture fiber ({hkl}ND representing crystallographic orientations with {hkl} planes parallel to the steel rolling plane). In contrast, the HIC-resistant steels show the weakest {001}ND texture fiber, the largest fraction of low-angle grain boundaries, and the strongest γ fiber. These results support the hypothesis of this and previous works, that crystallographic texture control, through warm rolling schedules, helps improve pipeline steel resistance to hydrogen-induced cracking.
Hydrogen-Induced Crack Interaction and Coalescence: The Role of Local Crystallographic Texture
Authors: Venegas V. , Caleyo F. , Hallen J. M. , Baudin T.
Published: April 2011

The role of local crystallographic texture (microtexture) in hydrogen-induced crack interaction and coalescence is investigated in pipeline steels using stress simulation and orientation imaging microscopy. It is shown that, depending on the material’s microtexture, crack interaction and coalescence can significantly depart from the conditions predicted by the mixed-mode fracture mechanics of isotropic linear elastic materials. The results of stress simulations and microtexture analyses conducted on several observed crack interaction zones show that the presence of cleavage planes and slip systems favorably oriented to the mixed-mode stresses can activate low-resistance transgranular paths along which cracks can merge. In such situations, the response of the material to the mixed-mode stress state resulting from crack interaction produces results drastically different to that predicted by the fracture mechanics of isotropic linear elastic materials. This evidences the need for considering the material’s crystallographic texture when developing predictive models for the stepwise propagation of hydrogen-induced cracking in pipeline steels.
Integrating ILI Data With Publicly Available Mapping Solutions
Authors: Coleman Grant A. , Miller Scott J.
Published: April 2011

Today’s’ high resolution ILI tools often incorporate extremely accurate Inertial Mapping Units (IMU) which provide spatial coordinates for every feature within a pipeline. This data may be useful across many levels of an organisation and so it is important to make the information available and practical. Google provides two near universally available mapping packages that may be easily leveraged to display GIS style data while in the field or in the office; Google Maps™ displays 2D information, while Google Earth™ provides 3D viewing. This paper presents several case studies where the use of Google Earth imagery combined with high resolution; inertially mapped MFL data provides immediate value to the pipeline operator.
Toughness Considerations for Strain-Based Design
Authors: Wang Yong-Yi , Liu Ming , Tyson Bill , Gianetto James , Horsley David
Published: April 2011

Toughness is a critical parameter in all phases of a pipeline service life. There are a variety of toughness testing forms, ranging from relatively inexpensive small-scale laboratory specimens to highly sophisticated full-scale tests. The correlation of physically significant parameters, such as transition temperature and upper shelf energy/toughness, from those test forms is examined. The ultimate objective is to understand of the similitude of various specimen forms. The similitude allows the prediction of large-scale behavior from small-scale laboratory test specimens. The paper presents data developed from various current and past research programs. The trends exhibited by the various forms of specimens are examined. The implications of those trends in the strain-based design of pipelines are summarized at the end of the paper.
Detection and In-Field Verification of Potential Pipeline Expansion Due to Low Yield Strength Pipe in High Strength Line Pipe
Authors: Braun Jill , Clouston Stuart
Published: April 2011

On May 21, 2009, the Pipeline & Hazardous Materials Safety Administration (PHMSA) issued an Advisory Bulletin (PHMSA-2009-0148) entitled, “Potential for Low and Variable Yield, Tensile Strength and Chemical Compositions in High Strength Line Pipe” [1] recommending that pipeline operators investigate whether recently constructed pipelines contain pipe joints not meeting the minimum specification requirements (74FR2390). Based on PHMSA’s technical reviews, high resolution deformation tool inspection combined with comprehensive infield verification has been recommended in accordance with the “Interim Guidelines for Confirming Pipe Strength in Pipe Susceptible to Low Yield Strength,” issued by PHMSA in September 2009[2]. Kern River Gas Transmission Company (Kern River) underwent a detailed program of engineering and assessment in order to proactively demonstrate compliance with the interim guidelines. This paper discusses the process, inspection results and infield verifications performed by the pipeline operator. In particular, detailed consideration to the methodology of detection and assessment of potential pipeline expansions is presented with discussion on the special considerations needed for low level anomaly identification, reporting and verification of expansions as defined in the PHMSA guidelines. High resolution caliper analysis approaches developed for this particular application are discussed and appropriate techniques are recommended that consider the effects of possible asymmetry of expansions and impact of other deformations such as ovality. Field verification practices and findings are reviewed in detail with particular focus on the challenges facing the pipeline operator in resolving both tool and in-field measurement errors that can significantly impact the number of identifiable candidate expansions for verification. In conclusion, an overview of the assessment criteria and field activity to comply with the PHMSA interim guidelines are presented along with the lessons learned from the analysis, verification and remediation steps that may assist other pipeline operators as they address these newly established regulatory requirements.
Reliability-Based Corrosion Management: The Impact of Maintenance and Implications for the Time to Next Inspection
Authors: Stephens Mark , Nessim Maher , van Roodselaar Albert
Published: April 2011

Quantitative analysis based on structural reliability methods is ideally suited to managing corrosion and cracking damage in pipelines as identified through in-line inspection. An ongoing industry-sponsored initiative has laid out a reliability-based process that is intended to form the basis for an industry-accepted approach to assessing and managing pipeline integrity with respect to these damage mechanisms, with an initial focus on metal-loss corrosion. The process combines appropriate failure prediction models, in-line inspection data, the physical and operational characteristics of the pipeline, and corrosion growth rate projections, within a probabilistic analysis framework, to estimate the likelihood of corrosion failure as a function of time. It also provides the means to assess the beneficial impact of selective and staged defect remediation and to evaluate candidate remediation strategies to determine the most cost-effective approach. This paper summarizes the reliability-based assessment and integrity management process. It also illustrates how the results provided can be used to determine the most cost-effective maintenance strategy in terms of the number of features to be remediated and the preferred time to next inspection.
An Approach for Evaluating and Prioritizing Dents for Remediation as Reported by ILI Tools
Authors: Arumugam Udayasankar , Kendrick David Z. , Limo´n-Tapia Sergio , Gao Ming
Published: April 2011

Analytical and experimental methods exist to help in the determination of critical strain levels for plain dents. Government regulations and industry standards require ranking the severity of dents reported by ILI tools for excavation primarily based on depth. These requirements also allow the use of engineering critical analysis methods to demonstrate that critical strain levels are not exceeded. This paper discusses the use of a laser mapping tool in conjunction with a modified method for determining static strains for prioritization and remediation of plain dents. The development of a correlation factor based on the examination of 6 dents and their respective ILI reports is presented and discussed. The application of the severity correlation factor to the remaining dents reported in the pipe section for their prioritization for remediation is also presented.
External Corrosion Growth-Rate From Soil Properties
Authors: Farrag Khalid A.
Published: April 2011

External corrosion growth rate is an essential parameter to establish the time interval between successive pipe integrity evaluations. Actual corrosion rates are difficult to measure or predict. NACE Standard RP0502 [1] recommends several methods including comparison with historical data, buried coupons, electrical resistance (ER), and Linear Polarization Resistance (LPR) measurements. This paper presents a testing program and procedure to validate the use of the LPR and ER methods to enhance the estimation of corrosion growth rates and improve the selection of reassessment intervals of gas transmission pipelines. Laboratory and field tests were performed using the LPR and ER technologies. The evaluation of soil parameters that affect localized corrosion included its type, moisture content, pH, resistivity, drainage characteristics, chloride and sulfite levels, and soil Redox potential. The results show that the LPR device provides instantaneous measurement of corrosion potential and it may be used to reflect the variations of corrosion rates with the changes of soil conditions, moisture, and temperature. However, LPR measurements are more efficient in saturated soils with uncertainty about its validity in partially and totally dry soils. Consequently, seasonal changes in soil conditions make it difficult to estimate total corrosion growth rate. On the other hand, the measurements using the ER method provided consistent estimates for long-term corrosion growth rates. Corrosion growth rates were also evaluated from a previous study by the National Institute of Standards (NIST) [2]. A procedure was developed to correlate soil properties to corrosion rates from the ER measurements and NIST data. The procedure was implemented in a computer program to provide an estimate of corrosion rate based on the soil input data and allows the operator to use the ER probes to improve the reliability of corrosion rate estimates.
Simulation of Long Term Pipe Exposure to Disbondment With an Advance Permeable Coating Model (PCM3.0)
Authors: Yan Li , Worthingham Robert
Published: April 2011

The Permeable Coating Model (PCM) is a mathematical model which has been developed to predict the generation and evolution of environments under a disbonded permeable coating as a consequence of the action of CP. The early version of the PCM was presented at IPC 2004, which focused on the prediction of the environment under a disbonded permeable coating in a fully water-saturated soil without including the generation of CO2 in the soil. As a consequence, the model predicted the generation of a high-pH environment for NaOH-based solution rather than a concentrated HCO3−/CO32− trapped water. The advanced version of PCM takes into account the generation of CO2 in soil by both microbial activity and plant roots respiration. Also, the concept of degree of saturation was introduced, which enables the PCM to predict the pipe surface conditions for situations in which the pipeline is either permanently above or below the water table. The simulation results from the advanced version of PCM show that the concentrated carbonate (i.e, 0.1 to 1 M) and high pH (> 9) environment required for high pH SCC, can be developed within 10 years with a CP level of −1.5VCSE and T > 25°C. For low temperatures (i.e., T ≤ 25°C) a time longer than 10 years is necessary to establish this concentrated carbonate and high pH environment. The results also suggest that although the necessary environment can be generated through the application of CP = −1.5 VCSE, the selected CP level does not cause the potential on the pipe surface to reach the critical potential range (i.e., −750 mVCSE to −600 mVCSE) required for high pH SCC. As expected, the loss of CP after an application of CP for 10 years could provide the environment needed for near-neutral pH SCC to occur.
Applicability of Plastic Eta Factor Solutions in J Estimation Procedures for Tensile SE(T) Fracture Specimens
Authors: Ruggieri Claudio
Published: April 2011

This work investigates application of the η-factor (which bears direct connection with laboratory toughness measurements) on accurate and robust estimates of J for clamped single edge notch tension (SE(T)) specimens made of homogeneous and welded materials using load-displacement records. Very detailed nonlinear finite element analyses for plane-strain models provide the evolution of load with increased load-line displacement and crack mouth opening displacement to define the applied load as a separable function dependent upon crack geometry, material deformation and mismatch level. The procedure enables determining the corresponding separation parameters for each specimen geometry thereby allowing evaluation of factor η derived from a load separation analysis. The study shows that η-factors based on load-displacement records defining the plastic area provide effective and accurate toughness measurements for clamped SE(T) fracture specimens. The analyses also revealed that η-factors for clamped SE(T) fracture specimens based on load-line displacement (LLD) records and plastic area are relatively insensitive to weld strength mismatch. Overall, the present results provide a strong support to use η-based procedures in toughness measurements using clamped SE(T) fracture specimens.
Finite Element Analysis of Cold Bend Pipes Under Bending Loads
Authors: Sen Millan , Cheng Roger
Published: April 2011

Cold bends are required in pipelines at locations of changes in horizontal or vertical direction in the right of way. Due to this change of direction, pipeline deformations caused by geotechnical or operational loading conditions tend to accumulate at the site of cold bends. These deformations may become sufficient to cause local buckling at the bend. For pipeline design, it is important to understand the level of deformation that a cold bend can accumulate prior to local buckling so that the strain capacity can be compared to the expected pipeline deformations. Evaluating the buckling strain of cold bends is extremely complex due to the residual stresses, ripples, and material transformations cause by the cold bending process. Accordingly a finite element model was developed herein. This model accounted for the cold bend geometry, initial imperfections, and the material transformations caused by the cold bending process. This model was validated against 7 full scale tests of cold bend pipes that were subjected to bend loading and internal pressure. The global and local behavior of this model exhibited reasonable correlation against the tests.
Evaluating the Performance of the Zap-Lok Connection System
Authors: Alexander Chris , Roberts David , Logan Robert
Published: April 2011

The Zap-Lok connection system involves a bell, or expanded area, formed on one end of a joint of pipe, and a groove is formed on the opposite end. Both end-forming operations are accomplished with a hydraulic belling unit and a hydraulic groover, respectively, operated by hydraulic power units. These end preparations are automatically controlled to specifications required for the Zap-Lok joint. In the field, or on the right-of-way, the belled end of one length of pipe and grooved end of another are forced together by the Zap-Lok joining press, with a thin coating of epoxy serving as a lubricant. The Zap-Lok joint is made cold and formed from the pipe itself. This process takes about 10 seconds, and it is normal to average 90 seconds per connection, including driving to the next joint. In the drive to lower costs for oil and gas operators, Zap-Lok is seen as a way to reduce costs of pipeline construction by 25% to 30% on land and by 45% to 60% offshore. Over the past several years an extensive testing program has been undertaken by Zap-Lok to evaluate the performance of their system, especially in relatively shallow water applications. This paper provides details on specific phases of the research program and the insights that were gained in the evaluation effort.
Finite Element Analysis of Fibre Augmented Steel Technology Pipe (FAST-Pipe™)
Authors: Yoosef-Ghodsi Nader , Salama Mamdouh , Chen Qishi
Published: April 2011

The FAST-Pipe™ concept involves wrapping a conventional strength steel pipe (e.g. X70), whose thickness is selected to satisfy axial and bending load requirement, with dry fibreglass to achieve the pressure load requirement. FAST-Pipe™ offers several technical and economical advantages over high strength steel concepts. Since FAST-Pipe™ is a new technology, there is a need to develop analytical methods for its design. This paper describes the finite element analysis (FEA) models used to predict experimental response. The calibration of the FEA models for FAST-Pipe™ involved the pressure-strain history, the burst pressure, the moment curvature history and the bending strain capacity of FAST-Pipe™ subjected to a combination of internal pressure, axial force and bending. The finite element program ABAQUS was used to develop shell models capable of simulating the burst and bending behaviour of FAST-Pipe™. Several burst and bend tests performed on 48- and 12-inch pipes were used to verify and calibrate the finite element analysis models. The effects of the type of steel-fibre bond, the thickness of the wrap, the wrap elastic modulus and the steel yield criteria were studied for the bend model. In the main FEA bend models, no bond was assumed to exist between the steel liner and the wrap in the hoop direction, and the steel liner was modelled using an elastic-plastic, kinematic hardening material model with an initially shifted yield surface. The failure of both the burst and bend models was defined as the point where the wrap hoop strain reached a failure strain of about 2%. The implementation of the FEA burst model was validated based on the burst test results. The assumption of no bond in the hoop direction and full bond in other directions resulted in reasonable predictions of the bending strain capacity. The autofrettage process influenced only the initial part of the moment-curvature response of a FAST-Pipe™ by producing a stiffer response, without significantly affecting the bending strain at failure and moment capacity. The wrap elastic modulus value and the type of yield criteria used for the steel liner had no significant effect on the moment capacity reached by the FEA models.
Effect of Soil Restraint on the Buckling Response of Buried Pipelines
Authors: Mahdavi Hiva , Kenny Shawn , Phillips Ryan , Popescu Radu
Published: April 2011

Long-term large deformation geohazards can impose excessive deformation on a buried pipeline. The ground displacement field may initiate pipeline deformation mechanisms that exceed design acceptance criteria with respect to serviceability requirements or ultimate limit states. Conventional engineering practice to define the peak moment or compressive strain limits for buried pipelines has been based on the pipeline mechanical response for in-air conditions. This methodology may be conservative as it ignores the soil effect that imposes geotechnical loads and restraint on buried pipelines. The importance of pipeline/soil interaction and load transfer mechanisms that may affect local buckling of buried pipelines is not well understood. The authors previously developed a new criterion for local buckling strain of buried pipelines in stiff clay through response surface methodology (RSM) [1, 2]. In this paper the new criterion was compared with a number of available in-air based criteria to study the effect of soil restraint on local buckling response of buried pipelines. This criterion predicted larger critical strain than selected in-air based criteria which shows the significant influence of soil presence. The supportive soil effect is discussed. The soil restraining effect increases the pipeline bending resistance, when the pipeline is subjected to large displacement-controlled ground deformation. A correlation between Palmer’s et al. (1990) conclusion [3] and current study’s results has been made. The critical strain increases as the ratio between axial thrust and pipeline bending stiffness decreases.
Development of X100 on Coil and First Weldability Assessment
Authors: Ruiz Romera D. , Liebeherr M. , Gu¨ngo¨r O¨ , Quidort D. , Ehlers S.
Published: April 2011

The development of X100, 13mm thick, on coil at ArcelorMittal is on schedule. Different steel compositions grouped in different categories A, C, D with various alloying contents and carbon equivalents have been tested by means of appropriate laboratory simulations. From these simulations, two different concepts have been developed, able to fulfil X100 strength properties in combination with excellent low temperature toughness. These two concepts are suited for low or high coiling temperatures (Type C and D respectively). The influence of the different TMCP (Thermomechanical controlled processing) parameters on the strength-toughness properties is shown and explained by the various microstructures. The low coiling temperature concept is based on a fine granular bainite microstructure avoiding the presence of M/A constituent and providing an excellent combination of strength and toughness. The high coiling temperature concept exhibits a quasi-polygonal ferrite microstructure with M/A as second phase. The M/A constituent seem to strengthen the steel without impairing the toughness while the quasi-polygonal ferritic matrix retains excellent toughness. A first assessment of the weldability has been done through the simulation and analysis of the heat affected zone for different cooling times between 800 and 50°C. The concept with a lower carbon equivalent (Type D) gives excellent weldability results.
Designing CO2 Transmission Pipelines Without Crack Arrestors
Authors: King Graeme G. , Kumar Satish
Published: April 2011

Masdar is developing several carbon capture projects from power plants, smelters, steel works, industrial facilities and oil and gas processing plants in Abu Dhabi in a phased series of projects. Captured CO2 will be transported in a new national CO2 pipeline network with a nominal capacity of 20×106 T/y to oil reservoirs where it will be injected for reservoir management and sequestration. Design of the pipeline network considered three primary factors in the selection of wall thickness and toughness, (a) steady and transient operating conditions, (b) prevention of longitudinal ductile fractures and (c) optimization of total project owning and operating costs. The paper explains how the three factors affect wall thickness and toughness. It sets out code requirements that must be satisfied when choosing wall thickness and gives details of how to calculate toughness to prevent propagation of long ductile fracture in CO2 pipelines. It then uses cost optimization to resolve contention between the different requirements and arrive at a safe and economical pipeline design. The design work selected a design pressure of 24.5 MPa, well above the critical point for CO2 and much higher than is normally seen in conventional oil and gas pipelines. Despite its high operating pressure, the proposed network will be one of the safest pipeline systems in the world today.
Thermo-Elastic Analysis of Thick-Walled Cylinders Made of Functionally Graded Materials Using Strain Gradient Elasticity
Authors: Sadeghi Hossein , Baghani Mostafa , Naghdabadi Reza
Published: April 2011

In this paper, strain gradient thermo-elasticity formulation for Functionally Graded (FG) thick-walled cylinders is presented. Elastic strain energy density function is considered to be a function of gradient of strain tensor in addition to the strain tensor. The material properties are assumed to vary according to power law in radial direction. Using the constitutive equations and equation of equilibrium in the cylindrical coordinates, fourth order non-homogenous governing equation for thermo-elastic analysis of thick-walled FG cylinders subjected to thermal and mechanical loadings is obtained and solved numerically. Results show that the intrinsic length parameter affects the stress distribution in FG thick-walled cylinders greatly and increasing the intrinsic length parameter reduces the maximum radial and hoop stresses. Also, the effect of FG power indices on the radial and hoop stresses are studied.
Design of Switching Damping Control for Smart Structure Self-Powered Adaptive Damping Control
Authors: Wu Chao-Ting , Yang Chih-Hsiang , Wu Wen-Jong , Lee Chih-Kung
Published: April 2011

This paper presents a new damping control circuit which named adaptive VSPD [1] (adaptive velocity-controlled switching piezoelectric damping) that can be used to vary control voltage of VSPD damping circuit with the amplitude variation and be self-powered itself as well. Since the voltage source in the VSPD damping control circuit may cause a stability problem at small vibrations, an adaptive voltage source can be designed to purposely solve this problem. The design concept of an adaptive VSPD unit is not only to dampen the residual vibration but also to maintain the system stability by incorporating an adaptive control voltage. In fact, the energy needed for the extra voltage source within the control circuit can be provided by the storage capacitor and the energy stored can be harvested from the structure vibration energy. With this design, the damping performance can be maximized while maintaining system stability at the same time and also does not add complexity to the circuit. All the theoretical modeling, simulation and experimental results will all be detailed in this paper.
Torsional Behavior of Shape Memory Alloy Tubes for Biomedical Applications
Authors: Chapman Cory , Karbaschi Zohreh , Elahinia Mohammad , Tabesh Majid
Published: April 2011

Shape memory alloys have been implemented in various applications throughout aerospace, biomedical, and various other fields. Some currently investigated applications of shape memory alloys include biomedical stents, rotary blade actuators, and pedicle screws for securing osteoporotic vertebrae. There have been many models developed by previous authors that discuss the reactions of this alloy in tension, compression, and one dimensional bending. It was the goal of this investigation to expand upon previous works to model the behavior of a shape memory alloy tube in pure torsion. The motivation for this investigation was the biomedical applications of this alloy. Because of its distinct properties of superelasticity and shape memory effect, the alloy is ideal for the design and implementation of medical devices that are smaller and more efficient than previous methods. The goal of this investigation was to model the properties of an SMA tube in torsion for use in an active orthoses for the treatment neuromuscular disorders and various other biomedical devices which involve the implementation of nitinol tubes in torsion. To this end, a model using COMSOL Multiphysics was developed which, in turn, will aid in predicting the behavior of an SMA tube under a torsional load and allow for calculation of an optimal torque tube for our applications. The outputs gained from this model were the angle of deformation under an applied torque, the resultant torque upon unloading of the tube, and the stress-strain relationships. From this information, different tube geometries will be experimentally tested to determine the best design for implementation. Once the analytical forces were determined from the SMA tubes using the COMSOL model, these results were then compared to experimental values from previous works to evaluate the accuracy of the model for the desired conditions.
Generic Models of Piezo-Actuators and Experimental Validation for Smart Applications
Authors: Boukari Abdou-Fadel , Moraru George , Carmona Jean-Claude , Malburet Francois , Chaaba Ali , Douimi Mohammed
Published: April 2011

In previous papers, we suggested piezo-actuators models and compared them to existing works with respect to sinusoidal solicitations. The current paper aims to experimentally validate and refine them. For this purpose, the piezo-device is integrated in a well known system. This reveals that the modeling of the whole system requires additional artefact and good choice of simulation methods. Then we study the whole system dynamics in order to check the validity of our models. Thereafter, the final model is reversed in order to elaborate control loops in smart applications.
Polycation Coated Polymeric Particles as Vehicles of RNA Delivery Into Immune Cells
Authors: Zheng Ying , Meng Wilson S.
Published: April 2011

The purpose of this work is to develop a carrier system for delivering RNA molecules aimed to downregulate specific functions in T cells. In many forms of cancer, T cells that express the protein Forkhead Box P3 (Foxp3) are associated with cancer progression. These cells can be identified by CD4 and CD25, molecules express on the cell surface. Studies have shown that downregulation of Foxp3 can increase the ability of other immune cells to destroy tumors. A class of RNA molecules, commonly referred to as “siRNA”, bind to and degrade specific messenger RNA (mRNA) in a sequence-dependent manner such that expression of the encoded protein is terminated. Because mRNA molecules are located inside cells, a carrier system is required to facilitate the uptake of siRNA, which does not passively diffuse through the plasma membrane. To this end, nanosized polymeric particles coated with the polycation, ornithinex10-histidinex6 (or O10H6) were used to adsorb siRNA that bind to the mRNA encoding Foxp3. The RNA-loaded particles are spherical and uniform in size (normally distributed, polydispersity index = 0.072). Loading of RNA to the particles was confirmed using gel electrophoresis. RNA complexed with the particles are protected from serum destabilization: 83.1% of RNA were recovered compared to 36.1% in RNA that were not associated with the particles. Association with the particles increased the uptake of the RNA in mouse T cells from 3.2±0.2% (free RNA) to 20.1±3.9%. Specifically, uptake of the RNA in T cells that express CD4 increased from 2.7±0.2% to 27.1±1.3% when particles were employed. These differences are statistically significant in three experiments conducted (p < 0.01). Internalization of the RNA into T cells was confirmed using confocal imaging. Flow cytometric analysis showed that the particle-complexed RNA reduced the percentage of T cells that express both CD4 and CD25 in mice carrying tumors from 24.0% when free RNA molecules were used to 13.5%. In these cells, the level of Foxp3 mRNA was reduced by 30%. In conclusion, the particles facilitate the uptake of siRNA molecules into a population of T cells that is known to promote cancer growth.
Multi-Location Actuators and Piezoceramic Based 2-D Spiral Array for Structural Health Monitoring: Thin Isotropic Panels
Authors: Yoo Byungseok , Pines Darryll J. , Purekar Ashish S.
Published: April 2011

In this paper, a new and robust 2-D phased array technique with multiple distributed actuators is studied for damage detection application based on Guided Lamb Wave (GLW) interrogation in a thin isotropic panel. A 2-D phased array technique using a single actuator located near the center of the 2-D phased array is unable to detect a linear crack oriented normal to the wavefront of the GLW excited from the actuator. To overcome this limitation, the 2-D phased array is coupled with multiple actuators in this study where the actuators are positioned at various locations on a test panel while the 2-D phased array is mounted at the center of the panel. A piezoceramic based 2-D phased array with a spiral configuration is used as a sensor array and the corresponding 2-D phased array signal processing is used to produce array responses and detect various damages. An innovative GLW propagation and reflection analysis technique is implemented to evaluate the damage locations in the panel. Experimental results demonstrate that the 2-D phased array damage detection technique using multiple distributed actuators can provide more robust damage detection scheme in thin isotropic panels than a technique with a single actuator element.