bluuebunny/crossref_metadata_2025 huggingface dataset:
Labour market characteristics and surviving import shocks
Authors: Chan Jeff
Published: January 2019

This paper investigates whether different labour market characteristics amplify or dampen the local labour market impacts from Chinese import competition exposure. I exploit state‐level variation in initial, pre‐shock labour market characteristics and regional variation across local labour markets in exposure to Chinese imports for identification. I find that local labour markets in states with higher union density experience more severe adverse consequences as a result of increased import exposure. Conversely, higher initial minimum wages help mute the negative impacts of the China shock. I also provide some evidence that exceptions to employment‐at‐will legislation can affect employment responses to increased Chinese imports. Finally, examining all policies together in an index, I show that higher levels of policies intended to benefit and protect workers can actually magnify the extent of the damage inflicted by import competition. My results suggest that initial labour market characteristics and policies can play an important role in understanding why local labour markets react differently to trade shocks.
Constraint Dominance Determination Methods
Authors: Rinderle James R. , Deshpande Ashish D.
Published: January 2019

Dominance among constraints exists when the satisfaction of a constraint guarantees the satisfaction of another, rendering the second constraint irrelevant. Identifying dominance not only facilitates numerical solution but may also focus the designer’s attention on critical aspects of the design. A number of dominance identification methods have been described in the literature, including the Constraint Difference Method, the Constraint Transformation Method, and the Necessary-Sufficient Interval Method. We elaborate on the basis for and the character of these methods and we discuss relative similarities, differences, strengths, and weaknesses of the methods. We also discuss computational issues relevant to the application of these methods, most specifically function range determination and interval analysis issues. We observe that the differences among the methods lead to advantages for each method in circumstances that depend on the nature of the constraints and the extent of the design space. These distinct advantages suggest a synergism among the methods in the identification of constraint dominance in complex design problems.
Inclusive Design: A Balance Between Product Demands and User Capabilities
Authors: Clarkson P. John , Keates Simeon
Published: January 2019

The world population is aging and the number of people who are experiencing a loss of functional capability is also on the increase. There is a need to design ‘inclusive’ products to accommodate this wider range of capabilities and to develop metrics to assess the success of such products. The case for inclusive design is presented as a balance between the demands a product makes of its users and the users’ capabilities, along with a number of design metrics and data to enable their evaluation.
Augmenting Mechanical CAD With Pen and Tablet
Authors: Dickinson John K. , Pardasani Ajit , Yu Zhisong , Zeng Yong , Antunes Helder , Li Zhenheng
Published: January 2019

Most designers and engineers tasked with creating concepts for a new machine or mechanical device do not first reach for their CAD station; they reach for pen and paper. However, designs generated on pen and paper often need to be redone in CAD systems and the prevalent belief is that capturing and processing these conceptual designs digitally from the start would save time, reduce errors, cut costs, prevent loss of prior concepts, add traceability, improve innovation and preserve expert knowledge. As preparation for a collaborative project building a tool to assist in the conceptual design of manufacturing/assembly systems, a broad current state of the art survey on pen-, table- and sketch-based design was done. This paper summarises part of that survey focussing on automated and/or interactive understanding of sketches of 3D systems, pen-based CAD, and existing systems exhibiting some of these technologies.
Iteration in Engineering Design: Inherent and Unavoidable or Product of Choices Made?
Authors: Costa Ramon , Sobek Durward K.
Published: January 2019

Iteration in design has different meanings, ranging from simple task repetition to heuristic reasoning processes. Determining the need to iterate is important to improve the design process on cost, time, and quality, but currently there is no categorization of iterations conducive to this goal. After exploring the possible causes and attempts to address them, we propose to classify iterations as rework, design, or behavioral. This framework suggests that design teams should try to eliminate rework iterations, perform design iterations without skipping abstraction levels, and do behavioral iterations in parallel.
Form-Generation System for Obtaining Diverse Design Solutions Supporting Early Process of Design in Structural Design
Authors: Inoue Masato , Matsuoka Yoshiyuki
Published: January 2019

Conventional structural optimization methods are difficult to apply to the early process of design referred to as conceptual design, in which diverse design solutions are to be obtained. This paper described a design method that obtains diverse design solutions. As a first step, a form-generation system that generates diverse forms is proposed. In this case, the diversity of organism was noted, and the form-generation method was referred to ‘induction’ and ‘apical dominance’ in the developmental process of organism. The proposed system, consisting of a generation process and an optimization process, was applied to the structural design of chairs, and the diversity of solutions was analyzed. As a result, it is shown that, as compared with conventional structural optimization methods, the proposed method obtains design solutions of adequate diversity. The results indicate the effectiveness of the proposed system for obtaining diverse design solutions.
Affordance-Based Methods for Design
Authors: Maier Jonathan R. A. , Fadel Georges M.
Published: January 2019

In previous work, the authors have suggested that the concept of affordance, a term borrowed from the field of perceptual psychology, should be considered as more fundamental to design than other concepts such as function and behavior. This paper continues this avenue of research by presenting a generalized theory of affordances applicable to design. Then several affordance-based methods for design are presented with brief examples. Methods are introduced for designing Artifact-User Affordances, Artifact-Artifact Affordances, various kinds of graphical affordance structures, embodiment design, and reverse engineering. The affordance-based methods presented offer a very different way of thinking from what would be used in a purely functional approach. In particular, the affordance-based methods emphasize satisfaction of user demands and wishes (what the artifact should afford) while safeguarding at each step against introducing unwanted or dangerous features (what the artifact should not afford). The affordance-based methods also lend themselves to taking advantage of the multiple afffordances of various objects, to achieve naturally what is sometimes termed “functional integration”.
Empirical Studies of Design Ideation: Alignment of Design Experiments With Lab Experiments
Authors: Shah Jami J. , Smith Steven M. , Vargas-Hernandez Noe , Gerkens David R. , Wulan Muqi
Published: January 2019

Although various Idea Generation (IG) methods exist for conceptual design, the ideation process is still hardly understood. There is a need for a Design Ideation Model that explains the variables and processes occurring during IG. Cognitive Science provides models and theories, but these are usually derived from simple tasks or problems. On the other hand, Design Research simulates real world design better, but experimentation at the design level is time consuming and is difficult to isolate due to interactions of the variables involved. This paper introduces an approach for the alignment of experiments at the design level with lab experiments in cognitive psychology. Two key concepts that make this alignment possible are: ideation components (mechanisms believed to promote IG) recognized in Design Research and Cognitive Science, and uniform measures. The long-term objective of this research is the creation of a Design Ideation Model; this will require the testing and modeling of several of these ideation components. This paper presents results from Design and Lab Experiments for a selected component: incubation. Results are discussed and their significance explained in the context of the Design Ideation Model. This study found that, based on the correlation at both the Lab and Design Experiments, incubation had a positive impact on Design Ideation. Further, the alignment approach followed proved to be appropriate for the individual modeling of ideation components.
Partitioning Knowledge for Generative Configuration Design
Authors: Shi Hai , Schmidt Linda
Published: January 2019

Designers and design researchers both agree that developing many feasible alternatives at the conceptual design stage is useful. In this paper we introduce generative configuration design (GCD) for conceptual design. We provide a partition of knowledge accessed during GCD and use the partitioned knowledge foundation to compare design tool architectures so that computational improvements can be made. We present an improved architecture for a GCD algorithm and implement it as a tool for office chair design. Subsequent examples show tradeoffs between computational load and design variety when applying constraints for behavior testing.
Improving Quality Management Systems (QMS) for Pipeline Construction Activities
Authors: Gould Melissa , Etheridge Brad , Amend Bill , Bruce William A.
Published: January 2019

Since 2007, the pipeline industry has experienced a large increase in pipeline construction. Construction inspections performed by the Department of Transportation (DOT) Pipeline Hazardous Materials Safety Administration (PHMSA) have revealed numerous quality issues. These inspections, coupled with several pre-commissioning pressure test failures, first year in-service failures, and other material and construction problems, brought construction quality to the attention of the oil and gas pipeline industry.

A proven method for improving quality in other industries is through the implementation of a quality management system (QMS). One widely accepted QMS used across industries is ISO 9001. Additionally, several QMS standards specific to the oil and gas industry have been developed. Due to the uniqueness of pipeline construction projects, PHMSA solicited proposals in 2013 for a research and development project titled, “Improving Quality Management Systems for Pipeline Construction Activities” which was awarded to and co-funded by DNV GL.

This paper describes the QMS framework for pipeline construction activities and an accompanying guidance document developed by DNV GL. The framework and guidance document are intended to assist pipeline operating companies and contractors in the development and implementation of a company-specific QMS, with a goal of elevating the focus on quality to the level of safety.

The framework adopts a risk-based, process approach, as defined in other QMS and management system documents, and follows the plan-do-act-check methodology. The QMS framework is designed to be scalable for a wide range of pipeline construction projects, including liquid and gas transmission pipelines and gas distribution lines. The framework includes the general management system components, as well as specific sections on implementation of a QMS for a pipeline construction project. The QMS framework and guidance document developed are intended to be used either as a stand-alone management system or as the quality component in a company’s corporate management system.
Capturing Best Practices for Third Party Inspections of Pipeline Construction
Authors: Montemurro David , McCaig Kim , Hoffmann Richard , Sahney Reena
Published: January 2019

The North American pipeline industry is facing a time of significant expansion over the next decade as a result of market demand and technology advancements that have fundamentally shifted supply and demand patterns in North America. While recent commodity prices have softened, the need for pipeline infrastructure may only be somewhat delayed, still allowing industry opportunity to improve practices in a number of areas. The INGAA Foundation and the Canadian Energy Pipeline Association (CEPA) Foundation have a number of initiatives underway in this respect; in particular, there is an emphasis on improving quality in all aspects of the pipeline construction process. One of the initiatives, described in this paper, relates to the compilation of a guide and body of knowledge for inspection practices and captures best practices as they relate to third party inspection during the construction process. The outlined approach is intended to have two main philosophical underpinnings: it must complement existing practices, training and certification, and it must remain user friendly and practical to use.

The main challenge in capturing best practices in this area lies in striking an appropriate balance between specific guidance regarding third party inspection and overly prescriptive, specific company practices. This is further complicated due to the broad range of topics and information required that is not always consistently documented across member companies. In light of these realities, the approach for the Practical Guide for Pipeline Construction Inspection was to align material required to perform an inspection task tightly to the sequential construction process to allow an intuitive layout for new industry entrants. Once a working group, representing both US and Canadian Operators and Services providers was established, a detailed table of contents was developed and agreed to by the group. Using this simple framework, available Member Company information was then reviewed, assessed and captured in detail for inclusion in the guide. The information took a range of forms ranging from specifications, manuals to training documents and modules. Significant collaboration, through working sessions, with Subject Matter Experts (SMEs), used to review, revise and supplement the content, as required. Overall, this approach provided a technically sound guide, addressing gaps in codified industry knowledge, while remaining relevant and accessible for most users.

Upon completion, this body of knowledge will be available for member companies to use immediately, and potentially, as a basis for training, individual study, and the further refinement of existing industry certification.
Investigation of Zinc- and Carbon-Nanoparticle-Based Nanocomposite Coatings
Authors: TabkhPaz Majid , Park Dong-Yeob , Park Simon
Published: January 2019

High performance coatings of pipelines should possess properties such as high adhesion to the substrate, low gas permeability, high corrosion resistance, etc. In this study, novel nanocomposite materials are studied for coating of steel plates. The coatings consist of two-layer composites with different nanoparticulates. Zinc particles, multi-walled carbon nanotubes (MWCNT), and graphene nanoplatelets (GNP) are used for the base layer bonded to the steel. Zinc particles are used as a filler and act as sacrificial anode against corrosion (cathodic protection). Hexagonal boron nitride (hBN) is added to the matrix for the second layers. Adhesion of the coatings is studied through pull-off tests. To examine the corrosion protection capabilities, cathodic disbondment tests are conducted on the coated steel plates. The gas permeability of the coatings is evaluated through a standard testing technique. Results show that addition of Zinc particulates could enhance corrosion protection. The addition of GNP and hBN nanoparticulates resulted in lower gas penetration. Results of this research will contribute to the development of advanced pipeline coatings.
Strain Capacity of Large Diameter Pipes: Full Scale Investigation With Influence of Girth Weld, Strip End Weld and Ageing Effects
Authors: Höhler Susanne , Karbasian Hossein , Gering Alexander , Kalwa Christoph , Ouaissa Brahim
Published: January 2019

The strain capacity of pipes under combined loading is a significant research topic if the pipes are provided for Strain Based Design scenarios. Displacement controlled scenarios such as ground movements may significantly affect transmission pipelines by inducing large amounts of plastic axial strains, which need to be considered in the design process. For these combined loading cases with internal pressure combined with pronounced longitudinal strains from environmental conditions it is essential to evaluate critical deformations on the one hand and to conclude the required structural performance and material parameters, on the other hand. Also pipe laying procedures introduce axial strains in pipes and pipe strings, e.g. cold bending of pipes for onshore pipelines, or S-Laying of offshore pipelines in combination with external pressure. For these cases also the strain capacity of the pipes and pipe connections must be guaranteed. In any case, the structural behaviour needs to be checked via full-scale tests to confirm and validate engineering approaches and computational models.

This paper presents a full-scale test series of UOE pipe X70 (OD = 914 mm, WT = 14.1 mm) and Spiral welded pipe X70 (OD = 1016 mm, WT = 20 mm) subject to internal pressure and bending load. Full-scale 4-point-bending tests on pipe joints subject to internal pressure were performed. The test series included the influence of girth weld, strip end weld for spiral pipe, and ageing effects of thermal treatment from coating process. The local bending strains measured via strain gauges and via optical strain measurements in the bending zone are evaluated for the tensile and compressive zone and discussed with respect to existing buckling models.

The results of the full-scale test program confirmed that the weld connections of the pipe joints are capable of withstanding bending load. The effects of the girth weld and strip end weld during bending test are analyzed and discussed. The test results are extended by finite element simulations that widen the experimental parameter range.
Knowledge Gained From a Five-Year Regulatory Compliance Assurance Process for Operators’ Pipeline Integrity Management Programs
Authors: Waheed Bushra , McAuliff Kelsey , Bhuyan Gouri
Published: January 2019

Pipelines are the most efficient and common infrastructure for the transportation of oil and gas. For Canadian pipeline operators, CSA Z662 Annex N is considered the industry standard for the development and implementation of integrity management programs (IMP) which include essential elements of policy and commitment; planning (goals, targets, organizational structure, roles and responsibilities, hazard identification, risk assessment and control); implementation (management of change, training and competency, documentation and record management); checking and corrective action (inspection, measurement and monitoring, investigating and reporting incidents, and internal audits); and management review elements over the lifecycle of a pipeline asset. In 2006, the British Columbia Oil and Gas Commission (Commission) made CSA Z662 Annex N mandatory for pipeline operators within its regulation. This paper provides an overview of the Commission’s compliance assurance process through the assessment of British Columbia’s pipeline operators’ IMPs and presents findings from the first five year (2011–15) assessment cycle. The analysis and trends of findings are presented in detail along with tracking of corrective actions. This paper also discusses knowledge gained from the compliance assurance process, along with the areas of proposed improvement to the current process for the next five year cycle. This includes alignment of the assessment process with the management system approach (using a risk based assessment process), improving regulation and the processes of compliance assurance and enforcement.
Risk Profiling for the Pipeline Industry: Application of Best Practices From the Aviation Industry
Authors: Harron Lorna , Turner Kimberley
Published: January 2019

Enbridge partnered with Aerosafe Risk Management to perform risk profiling to assist strategic planning activities aimed at safety performance improvement. A preliminary risk report, the first step towards an Industry Risk Profile (IRP) was the outcome. An IRP presents a strategic view of the risks within an industry sector at a point in time, requiring input from many stakeholders including operators, associations, and regulators. Most importantly, an IRP facilitates joint solutioning of risks to achieve improved safety performance and industry wide risk reduction. The preliminary risk report considered Enbridge data in addition to publically available information from associations and regulators to produce a preliminary risk report. The data gathering process considered information related to governance and oversight, compliance regime, assurance model, asset capabilities, industry operating environment, industry safety profile, and operator profile.

Results of the preliminary risk report are shared in this paper, with applicability to other operators, associations, and regulators. Providing the first building block of the IRP, these results focus on how organizations like Enbridge who aspire to participate or lead industry level reform or change can use the data to reshape their corporate risk based decision making. This approach, if adopted more broadly across the industry could provide as far reaching results as those seen in the aviation, military and transport sectors.

The IRP methodology and approach developed by Aerosafe in the mid-2000s, is now well entrenched in the aviation industry and is used by regulators and industry alike to create a pathway for industry level risk reduction and notable reform. The use of an IRP is considered best practices by the aviation, transport and regulatory sectors in the USA, Canada, Australia and New Zealand and after being in use in some sectors of aviation around the globe since 2008, the results are now measurable. These results provide a strong and clear link between safety performance improvement and the management and reduction of the industry risk profile.
Assessment of Stress-Displacement State of Cable Suspended Pipeline Bridge During Inspection Pig Motion
Authors: Orynyak Igor , Burak Igor , Okhrimchuk Sergiy , Novikov Andrii , Pashchenko Andrii
Published: January 2019

Designing and maintenance of pipeline cable bridge with dynamic loads is complex because this problem belongs to the geometrically nonlinear problems. Analysis shown that existing mathematics models of cables have restrictions in use and we can’t use these cable models for dynamic loads calculations of cable-suspended pipeline bridge. Movement, produced by motion of inspection pig inside pipeline is an example of such dynamic loads. During its motion through the pipeline cable bridge the inspection pig induces additional stresses in pipeline due its weight and finite velocity which induces the vibration of the bridge. Its stress state assessment requires a lot of modeling, measuring and calculating actions to be done. First of all the initial static stress state of the cable bridge should be evaluated. It depends on the existing tension forces in the cable elements. They approximately were derived from the optical measurement of their geometrical curvatures with accounting for known weight density of the cables. Then, existing software tool for piping stress calculation “3D Pipe Master”, which operates by 12 degrees of freedom in pipe elements, was modernized to be able to take into account the geometrically nonlinear behavior of 6 d.o.f. cable elements. The equations which relate the elongations and rotations of cable elements with tension forces in cables are written in the form convenient for application of the transfer matrix method in the linearized iteration procedure which adjusts the measured displacements of the elements of the bridge with calculated one. In this way the initial tension forces in cables, in particular, and the bridge state, in general were determined. The dynamic part of the problem is solved by expansion in terms of natural frequencies eigenfunctions. Given inspection pig velocity calculation allows to determine the time dependence of generalized loads for each of natural vibration mode as product of the pig weight multiplied by mode shape displacement in point of pig position at the given time moment. Eventually the technique of Duhamel integral is used to calculate the dynamic behavior of the bridge for each natural mode of vibration. Two examples of dynamic stress calculation are considered. First is primitive one and relate to calculation joint interaction pipeline and cable system at dynamic loading. The second example concerns dynamic calculation pipeline cable bridge through the river Svicha during movement inspection pig. This bridge consists of two support, two parallel pipelines (1220×15) with bends and cable system. Analysis shown possibility uses “3D Pipe Master” software for the solving problems of durability pipeline cable bridge any complexity in the conditions of static and dynamic loading.
A Collaborative Approach to Safety: Applying Lessons Learned From Other High Risk Industries
Authors: Munro John , Sommer Garry
Published: January 2019

Pipeline companies are facing an unprecedented era of challenges at an industry-wide scale. Recent incidents have increased public attention and criticism, cast doubts over the industry’s safety performance, and resulted in growing regulatory pressures. However, such a story is not unique to the pipeline sector. Other high-risk industries have experienced similar trials, and history may provide a blueprint for pipeline operators to follow.

This paper examines industries which have undergone significant changes in behavior due to catastrophic incidents. To address safety performance issues, public outcry and regulatory concerns, these industries emphasized the need for greater collaboration. Whether through encouragement of best practices via self-governance models, increased learning from incidents through sharing of data, or providing support to companies that were lagging behind, they concluded that it was imperative to move forward in a coordinated, collaborative fashion. Companies could no longer be satisfied with exceptional performance within their own walls, as they were ultimately answerable to the performance of their industry as a whole.

In many ways the pipeline industry has similar challenges to face. The relatively low frequency of high consequence incidents means that it is difficult for any single operator to gather statistically meaningful trends. ILI technology requires vast quantities of data to understand, validate and improve performance; quantities beyond what any single operator is likely to possess. No operator can effectively address the challenges of today’s environment single-handedly. It is only through coordinated, collaborative engagement throughout industry that rapid and meaningful improvement to pipeline safety will be achieved.

This paper suggests a variety of possible strategies and is intended to encourage discussion among leadership and managers regarding how the pipeline industry can come together more effectively to address industry safety issues in a unified fashion.
Physical Modelling on Buried Pipeline Response in Elasto-Viscoplastic Soils
Authors: Wong C. K. , Wan R. G. , Wong R. , Liu B.
Published: January 2019

Buried pipeline systems may traverse sections of unstable soil masses. Long-term ground movement may induce large strains on the pipe over time. To maintain the integrity of the pipeline, pipeline engineers and designers need to assess the frequency of critical ground movements to perform necessary remediation such as a stress relief procedure to prolong pipeline operation. The frequency of applying necessary remediation measures will vary depending on the rate of soil displacement in elasto-viscoplastic soils such as clay. Previous experimental work on simulating soil-pipe interactions was completed extensively on granular soils such as sand. Thus, an experimental program in simulating soil-pipe interaction for buried pipes in elasto-viscoplastic soils is highlighted in this paper. The experimental setup comprises a steel soil chamber (0.9 m in width and height, 2.4 m in length) with a steel pipe (150 mm diameter) being embedded in a compacted clay inside the chamber. The pipe is subjected to relative longitudinal, vertical uplift, and horizontal transverse displacements. The equipment setup has the ability to control and vary the displacement rate of the pipe. Hence, the effect of various displacement rates on the system response or the subgrade reaction can be studied. The system response or the subgrade reaction is recorded in a data acquisition system. In this paper, preliminary results of a vertical uplift test will be compared with existing guidelines from the American Lifelines Alliance (ALA). The ALA guidelines have yet to incorporate the effect of varying soil displacement rates in determining maximum loads subjected onto a pipeline.
The Effect of Corrosion Growth Model Assumptions on the Reliability Estimates of Corroded Pipelines
Authors: Dann Markus R. , Huyse Luc
Published: January 2019

Corrosion growth models are used to estimate future metal loss and the safe remaining lifetime of corrosion features in pipelines. Probabilistic models have become increasingly important in practice for reliability and risk-based pipeline assessments. The unknown model variables are usually determined from in-line inspection (ILI) results. Corrosion growth models exhibit various levels of complexity to account for temporal and spatial uncertainties of the actual corrosion growth process, and measurement uncertainties associated with ILIs. Model diversity leads to significant differences in how the models approach the uncertainty of future corrosion growth.

This paper builds upon previous work and provides some theoretical background to an application described in [1]. It compares four common probabilistic corrosion growth models with respect to reliability estimates of leak failure. The four models are two uncertain corrosion rate models and two stochastic process models where the features are considered to be either independent or exchangeable. The unknown random variables of each model are updated in a Bayesian manner using the same ILI results. The key findings of this paper are:

• Proper truncation at zero of the probability distributions for the unknown random variables is necessary if the measured corrosion growth is near zero or negative.

• A stochastic process leads to lower uncertainties when determining future metal loss and, consequently, an increased reliability against leak failure than corrosion rate models.

• The assumption of exchangeable features causes a reduction in the probability of leak failure due to the effect of borrowing information compared to independent features.

The four corrosion growth models provide similar results with respect to the probability of failure if the measured corrosion growth is large. As the measured corrosion growth decreases in size, the differences between the reliability estimates increase.
Design of Experiment and Validation of Model for Offshore Buried Pipeline Thermal Analysis
Authors: Chakraborty Suvra , Talimi Vandad , Muzychka Yuri , McAffee Rodney , Piercey Gerry
Published: January 2019

Buried pipeline heat transfer modeling has become an important topic in the Oil and Gas industry. The viscosity of fluid i.e. crude oil travelling through the buried pipeline largely depends on the flow temperature and pressure. The aim of this paper is to give an overview of designing the experiment for heat loss from offshore buried pipelines and validation of the experimental model using analytical solution and CFD modeling.

Several benchmark tests have been performed to ensure the validity of the test using theoretical shape factor models which depend on the amount of heat flow, thermal conductivity and geometry of the surrounding medium. This theoretical model has limitations such as the assumption of uniform soil properties around the buried pipeline, isothermal outer surface of the buried pipeline and soil surface. This paper illustrates several steady state and transient experiments to simulate the mechanism of heat loss from an offshore buried pipeline along with the experimental procedures. This paper also shows the transient response for shutdown tests performed in dry sand medium with numerical runs as well. With the progress of the research, several investigations will be made using different burial depths and diameters of the buried pipeline with backfill materials and trenching for different soil conditions, affecting the actual behavior of the model.
Influence of Material Anisotropy on the Compressive Strain Capacity
Authors: Koduru Smitha D. , Fraser Alex M. , Yoosef-Ghodsi Nader , Chen Qishi
Published: January 2019

Assessment of compressive strain capacity forms one of the critical components of the strain-based design. For pipeline-specific capacity assessments, detailed finite-element (FE) models are generally employed. However, the modelling approach taken to represent pipeline material anisotropy in the FE analysis may have a considerable influence on the computed compressive strain capacity. This study presents a new approach for the representation of material anisotropy in FE models and demonstrates the influence of material anisotropy on the compressive strain capacity with the aid of two case studies using pipeline materials for X60 and X80 grade steel. Results indicate that material anisotropy reduces the compressive strain capacity by up to 30% compared to the capacity prediction using axial tension material properties. If material anisotropy is to be ignored, in order to assess the lowest value of compressive strain capacity it is recommended that the material representation with highest yield strength and yield to tensile strength ratio be selected among the hoop tension, axial tension, and axial compression coupon test results.
Viscosity Variation of Ice Suspensions Formed From Water-in-Oil Emulsions
Authors: Zheng Haimin , Huang Qiyu , Wang Wei
Published: January 2019

Multiphase transportation is widely used as the oilfield development moving into deepwater. Temperatures will have a drop when multiphase flow from normal region to cold region in the subsea pipelines or experience Joule-Thomson cooling in choke valves. The unexpected temperature drop can lead to viscosity increase and ice suspensions formation, and even ice blockage. In this study, viscosity variation of ice suspensions formed from water-in-oil emulsions was measured. Viscosity started to increase when ice suspension was forming. The experimental results showed that viscosity increased firstly until a maximum value upon ice formation and then decrease to a stable value in the process of ice suspension formed from w/o emulsion. So the critical viscosity included a maximum value and a stable value. The effects of temperature (subcooling) and shear rates on viscosity variation were investigated. Experimental results indicated that ice suspension viscosity increased faster with lower temperature (larger subcooling) and stronger shear disturbance. Heat transfer was a principle factor that determined viscosity increase in the process of ice suspensions formation. Therefore, good insulation of subsea pipelines is required to avoid ice blockage when emulsion flow from normal region to cold region.
Multi-Phase CFD Modelling of CO2 Releases From High-Pressure Pipelines
Authors: Liu Xiong , Godbole Ajit , Lu Cheng , Liu Bin , Venton Philip
Published: January 2019

An accurate prediction of the ‘source strength’ of CO2 released from high-pressure pipelines is of great importance for risk assessment, because this parameter determines the subsequent dispersion in the atmosphere. The widely used method is to employ a one-dimensional discharge model describing the conservation of mass, momentum and energy. The fluid is usually considered to remain at thermal and mechanical equilibrium during the depressurisation process, while the non-equilibrium liquid/vapour transition phenomena are ignored. Although efforts have been made to model non-equilibrium, two-phase CO2 depressurisation in recent years, possible improvement can be made by using a more precise Equation of State (EOS) and more detailed models.

In this paper, a multi-phase Computational Fluid Dynamics (CFD) model is presented to simulate CO2 releases from high-pressure pipelines. A real gas EOS (GERG-2008) was incorporated into the CFD code. This enabled accurate modelling of the thermodynamic properties to achieve a more precise source strength estimate. The non-equilibrium liquid/vapour transition was modelled by introducing source terms for mass and latent heat. A ‘time relaxation factor’ was used to control the inter-phase mass transfer rate. The CFD model was validated against experimental results from the British Petroleum (BP) CO2 release trials. The optimum relaxation time (for the CO2 depressurisation cases tested) was obtained through simulations by varying the time relaxation factors and comparison with experimental data. In addition, the effect of the relaxation time on the source strength prediction is discussed.
A Case Study on the Application of Structural Reliability Analysis to Assess Integrity for Internal Corrosion of Unpiggable Pipelines
Authors: Taylor Katherine , Turner Susannah , Goodfellow Graham
Published: January 2019

Operators wish to understand the condition of their pipelines to manage ongoing integrity. Information on the condition of the pipeline along its entire length can be obtained using in-line inspection (ILI). However, some pipelines cannot be internally inspected due, for example, to tee connections, tight bends, low flow or to a lack of launcher and receiver facilities. The condition of these ‘unpiggable’ lines can sometimes be largely unknown. To aid the understating of the pipeline condition without ILI data, operators will often rely on alternative sources of information, such as localised external inspections, model predictions and company and individual experience. However, there may be significant uncertainty associated with these alternative data sources when using them to assess the condition of the entire pipeline. This uncertainty may be understood by applying a probabilistic approach to the assessment of pipeline integrity using structural reliability analysis (SRA) methods.

An SRA approach applies probabilistic input parameters to a failure prediction model for a defined limit state function. Previous IPC papers[1,2,3] have presented guidance on probabilistic assessments to model pipeline failure. Recommended probability distributions are presented which account for uncertainties associated with line pipe properties, defect sizing and the error associated with the predicted failure model. However, there is little published guidance readily available on recommended defect characteristic distributions specific to internal corrosion features. Parameter distributions are recommended for defect sizing based on empirical data, which are mainly used for external corrosion features.

In this paper, a case study is used to present a practical application of an SRA methodology for assessment of pipeline integrity with respect to internal corrosion. Discussion is presented on alternative sources of information for the assessment when ILI data is unavailable, including targeted external inspections of unpiggable lines and data sets from comparable piggable lines. Probability distributions are derived from the available inspection data for the internal corrosion feature size and corrosion rate input parameters to the SRA. Probabilistic analysis is used to account for the expected population of unknown features in the uninspected parts of the pipelines. The expected feature size, corrosion rate and feature density calculated are used in the SRA to estimate the total probability of failure due to internal corrosion over time for the entire length of the pipeline. Recommendations are provided on the application of an SRA methodology to assess pipeline failure due to internal corrosion.
Strain Capacity and Deformation Behavior of HFW Linepipe
Authors: Igi Satoshi , Yabumoto Satoru , Sadasue Teruki , Tajika Hisakazu , Oi Kenji
Published: January 2019

Newly-developed high quality high frequency electric resistance welded (HFW) linepipes have recently been applied to offshore pipelines by using the reel-lay method and onshore in extremely low temperature environments because of their excellent low temperature weld toughness and cost effectiveness. In order to clarify the applicability of these HFW linepipes to seismic regions, a series of full-scale tests such as the bending test with internal pressure and the uniaxial compression test were conducted according to the seismic design code of the Japan Gas Association (JGA).

Based on these full-scale tests, the safety performance of high quality HFW linepipe when applied to seismic regions is discussed in comparison with the mechanical properties obtained in small-scale tests, such as the tensile and compression properties of the base material and weld seam, focusing especially on the compressive and tensile strain capacity of HFW linepipes from the viewpoints of full-scale performance and geometrical imperfections.

The results of the bending test under internal pressure and the uniaxial compression test without internal pressure complied with the JGA seismic design code for permanent ground deformation induced by lateral spreading and surface faults.

In addition, a full-pipe tension test was also conducted in order to investigate the tensile strain capacity of HFW linepipes for axial deformation.
Critical Review of Risk Criteria for Natural Gas Pipelines
Authors: Tomic Aleksandar , Kariyawasam Shahani
Published: January 2019

Risk Assessment is an integral part of an Integrity Management Program (IMP), and it is generally the first step in most IMPs. Risk is of the product of two variables, the likelihood of failure and the consequence of failure, where failure is defined as a loss of containment event. Hence, it is necessary to calculate both variables in order to accurately model risk. To assess risk, criterion need to be established and the actual risk needs to be compared to the criterion in order to determine the acceptability of risk.

Currently, most industry risk assessment models are qualitative risk models, where consequence is generally characterized by class, relative population measures, or some other relative measure. While this may be adequate for some relative risk ranking purposes, it is generally not accurate in representing the true consequences and the arbitrary nature leads to overly conservative or overly un-conservative results.

Conversely, Quantitative Risk Assessment (QRA) models take into account the effect of the thermal radiation due to ignited pipeline rupture and evaluate the consequence on the surrounding human population. Such a consequence model is dependent on the pipeline properties (i.e. diameter and MOP) and the structure properties (i.e. precise locations and types of structures). The overall risk is then represented by two specific, well defined measures: Individual Risk (IR) and Societal Risk (SR). The goal of this paper is to perform a critical review of IR and SR acceptability criteria that are widely available and widely used, and outline the criteria (and the approach) adapted by TransCanada Pipelines.

Worldwide, there are several different standards that define the criteria for evaluating IR and SR, particularly some countries with higher population densities around pipelines (e.g. UK and Netherlands). These IR and SR criteria have been compared in a hypothetical case study, to determine the most appropriate method in terms of the assumptions for calculating risks, the criteria, and how the actual risks compares to the criteria. The outcome of this study was the adoption of a defendable process for calculating SR, along with the associated criterion.
Failure Frequency Calculation of Transmission Pipelines or Stations due to Nearby Wind Turbines
Authors: Coster Roelof P. , Middel Martijn T. , Dröge Marc T.
Published: January 2019

The present article discusses the methodology to include potential wind turbine failures in quantified risk assessments (QRA) of transmission pipelines or stations, which is included in the latest version of the Dutch national ‘Handbook on Risk Zoning of Wind Turbines’ (‘Handboek Risicozonering Windturbines’) [1].

The methodology includes a simple set of wind turbine failure modes and frequencies, probability density functions and failure criteria of the impacted underground pipeline or aboveground station components. Using the methodology, an additional failure frequency can be calculated for a transmission pipeline or a station due to the presence of one or several wind turbines.

The focus of the methodology is not on the physics of each of the separate scenarios (many different studies and approaches are publically available), but as a practical tool for quantified risk assessments and determination of acceptable siting distances for wind turbines near gas infrastructure. The pressure and the (possibly non-uniform) construction parameters and depth of cover of underground pipelines are taken into account in the calculations.

The methodology shown in this article was developed by DNV GL and published in Netherlands Enterprise Agency’s ‘Handbook on Risk Zoning of Wind Turbines’ in May of 2013. Following the publication of this Handbook, a software tool has been developed to implement the calculation method. This software is also discussed in this article.
System-Wide Response to Incidents: Case Study
Authors: Zhang S. , Kariyawasam S. , Sutherby R. , Upadhyaya J.
Published: January 2019

This paper presents a systematic and comprehensive procedure for the system-wide response to incidents (SWRI). This SWRI process has been used for identifying emerging threats and incorporating the learnings from major incidents into a pipeline integrity management program (IMP). This process also complements the IMP for threat identification and system wide risk assessment, thus giving consideration to all known threats and their interactions. A recent major incident due to thermal expansion on a TransCanada pipeline system was used to demonstrate the process of SWRI and the use of SWRI to identify the contributing factors of thermal expansion. An example was used to illustrate the engineering assessment for thermal expansion driven by the construction of two new compressor stations on an existing pipeline. The process documented in this case study has the potential to augment the integrity management programs and systemic corrective actions for pipeline systems in the energy industry.