bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Heuristics and Biases Impact Judgment and Decision Making in Well Integrity Operations
Authors: Teodoriu Catalin , Salehi Saeed 
Published: November 2019

Abstract
The contribution of the human factor in major oil and gas accident events is fully-fledged and admitted. The root cause analysis and incident investigation of these accidents reveal that many of them could have been prevented, with the perception that there was a cascade of failures in human factor elements. This is easy to comprehend, as the human factor has not been accentuated thoroughly in this industry and traditionally the focus has been on personnel knowledge and competence.
A previous paper presented at OMAE 2018 had a brief overview of well integrity, and the pivotal role of cementing operations in well control. The critical role of human and organizational factors in cementing operations and well control was addressed. Furthermore, an outline of the newly implemented SEMS II regulations was also offered, with insight into adjustments that could enhance this program’s modest requirements.
In this paper, the goal is to examine the key heuristics that operational people employ in well integrity procedures. Some of these cognitive biases include status-quo and confirmation biases. Several examples will be discussed to show how underlying biases can lead to improper decisions. Unfortunately, some of these biases have been embedded in companies cultures for several decades now, and are hard to change overnight. Some of these can often lead to tremendous operational costs and not necessary solving the problem. It is highly recommended that training schools consider the problems of psychological biases and start implementing case studies for improvement in judgment and decision making.
Evaluation and Optimization of Trimaran Configurations Using Deep Neural Network
Authors: Yu Dongchi , Wang Lu , Zhong Qian , Yeung Ronald W. 
Published: November 2019

Abstract
To determine the optimal trimaran configuration for best calm-water transportation efficiency, a Deep Neural Network (DNN) is trained with sufficient computational results provided by, as an example, an in-house developed potential-flow code called Multi-hull Simple-source Panel Method (MSPM). Even though the computational method is extremely efficient in accurately establishing the mapping relation between the key design parameters governing the trimaran configuration problem and the resulting calm-water transportation cost, the modeling efforts are non-trivial since the number of geometric and configuration parameters in a typical situation is large. In this work, we demonstrate how the “Big Data” of computational results can be effectively utilized in training a DNN. An optimal trimaran configuration solution within a specified design space, subject to realistic range constraints, can be quickly determined in a minimal amount of time with the DNN. A demonstrative case study is provided for illustration.
B31 J SIF and k-Factor Test of Sweeplus®
Authors: Liu Yuqing , El Jaouhari Ismat , Diwakar Philip , Lin Dan 
Published: November 2019

Abstract
Formerly, an entire catalogue of 90 deg. branch connections called Sweeplus® was developed and accessed to mitigate acoustic induced vibration (AIV) in piping systems exposed to high frequency vibration. Parameters related to cyclic loading was completed on the Sweeplus® fitting to determine the stress intensification factor (SIF) and flexibility factor (k-factor), in accordance with the latest revision of ASME B31J-2017 code and reported in this paper. A Sweeplus® fitting was welded in a Markl test fixture and controlled through LabView software. The testing configuration and equipment were those used in Kahn test reported in WRC 329. K-factor tests were conducted for the in-plane thru both branch and header piping, and the out-of-plane thru branch. SIF tests were performed in the out-of-plane thru branch. The tests confirmed the SIF of Sweeplus® is less than one which means the fatigue life of Sweeplus® is significantly extended, not only under high frequency AIV excitation, but also under low frequency flow induced vibration (FIV) and thermal loading.
Sustained Pressure Test Results for Surface Scratches in PE4710, Cell Classification 445574C High Density Polyethylene Pipe Material
Authors: Hebeisen Jason , Adams Timothy M. , Munson Douglas 
Published: November 2019

Abstract
Mandatory Appendix XXVI of the ASME Boiler and Pressure Vessel Code (BPVC), Section III, Division 1 currently permits the use of high-density polyethylene (HDPE) in buried safety Class 3 piping systems. There have been concerns about how the slow crack growth (SCG) of HDPE emanating from surface scratches that may occur during fabrication or installation. The current allowable scratch depth in Appendix XXVI is 5% of the pipe wall thickness for pipe 4 inch and less in nominal diameter pipe and 0.040 inch (1mm) for pipe greater than 4 inch nominal diameter. This report presents the results of further investigation into the SCG rates by testing of notched PE 4710 HDPE pipes made from PE 4710 cell classification 445574C bimodal resins that meet the requirements of Appendix XXVI. These tests were conducted by first making razor-cut surface scratches in 4 inch, 8 inch, and 16 inch nominal diameter piping made by three different piping manufacturers using three different resins. The pipes were end-capped and pressure-tested at elevated temperature until failure, or until a prescribed number of test hours were reached. The razor cuts were at different depths and lengths so as to result in a variety of stress intensities, net section stresses, and nominal stresses. Following failure, or after the prescribed number of test hours was reached, the pipe specimens were inspected to determine the amount of SCG. This paper presents the results of the testing and recommended ASME BPVC Appendix XXVI changes for allowable crack depth based on the testing are provided.
Dancing Manhole Cover: A Nonlinear Spring-Mass System
Authors: Tijsseling Arris S. , Vasconcelos Jose G. , Hou Qingzhi , Bozkuş Zafer 
Published: November 2019

Abstract
Dancing manhole covers are an intriguing and curious phenomenon but extremely dangerous for road vehicles as well as pedestrians. They are reported worldwide after heavy rainfall in urban environment. Stormwater systems are overloaded with running water containing large entrapped air pockets for which manholes form an escape route. However, heavy lids cover the manholes and they are supposed not to move.
An attempt is made to understand the physics behind dancing manhole covers by means of simple spring-massdashpot modeling. The ingredients are liquid slugs, air pockets, and fluid-structure interaction.
Modification of the MPC Omega Model to Predict Primary and Tertiary Creep
Authors: Haque Mohammad Shafinul 
Published: November 2019

Abstract
The MPC Omega model has become popular in recent years for the prediction of creep deformation. Successful predictions of the tertiary creep for a wide range of materials are available. The Omega model relates the strain as a linear function of the natural logarithm of strain-rate. It is assumed that the primary creep is a short-lived phenomenon and can be neglected. The Omega model is unable to predict the primary creep deformation. Often primary creep is a long-lived phenomenon and cannot be neglected. A mathematical modification can be performed to incorporate the primary creep curve in the Omega model. A common approach is by adding a work hardening function to the original constitutive model. Approaches using power, or exponential, or logarithmic work-hardening function are available. However, it is difficult to discern which function is the best for accurate prediction. In this study, the Omega model is modified to predict the primary and tertiary creep deformation curve by adding a hyperbolic tangent work hardening function. A metamodel incorporating the four modified Omega sub-models (power, exponential, logarithmic and hyperbolic tangent) is developed. The metamodel enables the determination of the most suitable model for a given material and avoids the force fit of a preselected model. Short, medium, and long-term creep deformation data for alloy P91 (pipe) and G91 (plate) at two isotherms of 600°C and 650°C are used to calibrate the metamodel. The data include five stress levels ranging from 70 to 160 MPa including creep life from 233 to 1.1 × 105 hrs. A detail calibration process is provided. A numerical analysis is performed to compare the four submodels. It is observed that the selection of the most suitable function depends on the loading condition and material properties. Based on the analysis, a recommendation to select the suitable work-hardening function to predict the primary and tertiary creep deformation curve is presented.
Repair of B31.1 Fiber Reinforced Polymer Piping System Using Carbon Fiber Reinforced Polymer
Authors: Hebeisen Jason , Adams Timothy M. , Dubovecky Bruce , Jimenez Tomas 
Published: November 2019

Abstract
This paper describes the use of Carbon Fiber Reinforced Polymer (CFRP) for the repair of leaking Fiber Reinforced Polymer (FRP) pipe. The existing piping system, which is used for slurry transport, consisted of straight pipe, reducers, and elbows connected by bell and spigot joints. The piping system was evaluated for pressure, deadweight, and fluid thrust loads in accordance with B31.1 Power Piping Code and ASME BPVC Section III, Code Case N-155. The pipe leaks and joint repairs were in accordance with ASME PCC-2 and ASME BPVC, Section III, Code Case N-155. The CFRP repair was done with Aegion TYFO® Fibrwrap® carbon fiber reinforced fiber wrap (TYFO SCH-41-2X) saturated with epoxy. The repair uses the unidirectional carbon fiber installed in layers 90° to each layer. The circumferential layers are used for hoop pressure stress while the axial layers restrain axial pressure, deadweight, and fluid thrust loadings on the pipe.
Proposal of New Code Case for Alternative UT Flaw Evaluation and Acceptance Criteria of Subsurface Flaw Near Component Surface in Section VIII Division 2 and Division 3
Authors: Terada Susumu 
Published: November 2019

Abstract
The current proximity rules for subsurface flaws near the surfaces of component in Section VIII Division 2 and Division 3 are different from those of Section XI. The current acceptance criteria of Sec. XI were revised in 2008 in order to eliminate the discontinuity of acceptable and unacceptable flaws based on the research work by Dr. K. Hasegawa and Dr. K. Miyazaki el. The fracture mechanics evaluation for the current and proposed alternative acceptance criteria for subsurface flaws near a component’s surfaces based on Section XI have been performed. The stress intensity factors for transformed surface flaws of the current acceptance criteria for subsurface flaws near component’s surfaces are much larger and too conservative compared with the overall acceptance criteria. It is confirmed herein that the proposed alternative converting rules have enough fracture margin. Therefore, the safety level of this proposal is almost the same as that of the current code. The proposed alternative acceptance criteria may avoid unnecessary weld repairs, and eliminate the discontinuity of acceptable and unacceptable flaws in the area near the component’s surface.
A Transfer Matrix Method for Free Vibration Analysis of Tapering Pipe
Authors: Zeng Qingna , Zang Fenggang , Zhang Yixiong , Wang Donghui 
Published: November 2019

Abstract
In this paper, theoretical solutions of free transverse vibration for tapering pipe considering variable cross section have been investigated using Bessel function in low frequency domain. Natural frequency was calculated by transfer matrix method (TMM) based on an accurate theoretical model. The effectiveness and validity of TMM with Bessel function was confirmed in comparison with TMM of discrete uniform pipe and Finite Element Method. Furthermore, dimensionless model was proposed to avoid the singularity, instability and overflow in calculation. The geometry effect, such as tapering ratio, thickness-radius and length-radius ratio influence on the nature frequency was explored. The present study was envisaged to provide useful insights for dynamic analysis of pipeline systems.
Environmentally-Assisted Fatigue Behavior of 316 Stainless Steels in Simulated PWR Primary Environment: Strain Holding, Zn-Addition, and Their Combined Effect
Authors: Lee Hyeon Bae , Kim Ho-Sub , Chen Junjie , Jang Changheui , Kim Tae Soon , Stevens Gary L. , Ahluwalia Kawaljit 
Published: November 2019

Abstract
Low cycle fatigue (LCF) tests of type 316 stainless steel (SS) were conducted in simulated pressurized water reactor (PWR) environments to evaluate the effect of zinc (Zn) content and peak strain holding. The LCF lives of 316 SS increased about 2 to 3 times in PWR environments with Zn addition and peak strain holding (Zn-PWRhold condition). Their combined effect was investigated by using cyclic hardening behavior, dislocation structure analysis, and oxide layer observation. The cyclic behavior in Zn-PWRhold condition showed general primary hardening behavior but quite longer softening behavior than other test conditions. Also, the dislocation density was decreased with Zn addition and increased again with peak strain holding. The Zn penetrates into the oxide layer at the crack tip and modifies the oxide characteristics, which results in improvement of corrosion resistance.
A Residual Lifetime Prediction Method of Aging Polyethylene Gas Pipes in Service
Authors: Wang Yang , Lan Hui-qing , Zhang Hao 
Published: November 2019

Abstract
Polyethylene pipes (PE) have been widely used for various urban gas pipeline transportation engineering. With the increase of service life, the aging of PE pipes has become a safety issue of urban gas pipeline transportation. Therefore, a practical prediction method for predicting the residual lifetime of in-service aging polyethylene pipe is needed. Hitherto, there are a few reports on the aging performance and lifetime prediction of PE pipes under the laboratory research stage, but there are few researches on lifetime prediction methods of in-service aging polyethylene pipes. In this paper, aging PE pipes under different pressures and temperatures were produced by an accelerated aging test which was used by a thermal oxygen aging experimental set-ups PE pipes. Aging PE pipes were respectively tested by a tensile test, DSC and MFR (Melt Mass Flow Rate), and the test’s results of aging PE pipes were analyzed comparatively. Then, a residual lifetime prediction equation of pressured gas PE pipes was proposed by Arrhenius fit of the data which comes from the test’s results. Basing on this equation, a residual lifetime prediction method of aging polyethylene gas pipes in service was proposed, that is, the DSC test data of the particle (about 15 mg) which is cut from the surface of the in-service polyethylene gas pipes can be substituted into the lifetime prediction equation to predict the residual lifetime of aging polyethylene pipes. This residual lifetime prediction method is not only suitable for pressured aging polyethylene gas pipes in service, but also for other pressured plastic pipes in service.
Electric Potential Drop Method for Evaluating Crack Initiation and Crack Propagation: The Help of FE Simulation
Authors: Le Delliou Patrick 
Published: November 2019

Abstract
The electric potential drop (EPD) method is a laboratory technique to monitor the initiation and the propagation of a crack, mainly in the field of fatigue research. It can also be used in fracture experiments, involving plasticity and large deformations. The size of a crack in a metallic member is predicted by applying a constant d.c. (direct current) or a.c. (alternating current) to the member and by measuring an increase in electric resistance due to the crack. Practically, several pairs of probes are attached to the specimen crossing over the crack and the voltage drop is measured periodically along the test. The main difficulty is to correlate the EPD changes to the crack extension.
Thanks to the analogy between the thermal conduction problem and the electrical conduction problem, a classical thermo-mechanical finite element solver can be used to predict the EPD along a crack, given the electrical resistivity of the material, the current intensity and the geometry of the structure and of the crack. This technique works well for fatigue studies, where the structure remains elastic and whose shape is unchanged. However, in fracture experiments, the change in geometry and the possible effect of the plastic strain on electrical resistivity make the problem much more complex.
The paper presents the principle of the EPD method, a work on the effect of the plastic strain on the electrical resistivity, FE computations for the elastic case (for fatigue pre-cracking) and for the plastic case (for ductile tearing experiments). Several practical applications will be presented on various metallic materials.
Analysis of Environmentally Assisted Cracking in S420 Steel by Using the Theory of Critical Distances
Authors: González P. , Cicero S. , Arroyo B. , Álvarez J. A. 
Published: November 2019

Abstract
The behavior of S420 steel under cathodic polarization in low pH aqueous environment is analyzed following the assumptions of the Theory of Critical Distances. This methodology has been successfully applied in fracture and fatigue analysis, but it has not been employed yet under stress corrosion cracking or hydrogen embrittlement conditions. This work focuses on the problem of environmentally assisted cracking by using the Point Method and the Line Method, both of them belonging to the Theory of Critical Distances. Fracture mechanic tests were carried out, using a slow strain rate machine, at two different solicitation rates (6·10−8 m/s and 6·10−9 m/s). The study is based on an experimental program composed of C(T) specimens with notch radii varying from 0 mm up to 2 mm. Cathodic polarization with a 5 mA/cm2 current has been employed and the aqueous aggressive environment was made using the Pressouyre’s method. The study has been completed with finite elements simulation analysis. The results reveal that the Theory of Critical Distances provides accurate predictions of the environmentally assisted cracking behavior of S420 steel in notched conditions.
Augmenting Generic Fatigue Crack Growth Models Using 3D Finite Element Simulations and Gaussian Process Modeling
Authors: Loghin Adrian , Ismonov Shakhrukh 
Published: November 2019

Abstract
Assessing the crack propagation life of components is a critical aspect in evaluating the overall structural integrity of a mechanical structure that poses a risk of failure. Engineers often rely on industry standards and fatigue crack growth tools such as NASGRO [1] and AFGROW [2] to perform life assessment for different structural components. A good understanding of material damage tolerant capabilities, and the component’s loading mission during service conditions are required along with the availability of generic fracture mechanics models implemented in the lifing tools. Three-dimensional (3D) linear elastic fracture mechanics (LEFM) finite element modeling (FEM) is also a viable alternative to simulate crack propagation in a component. This method allows capturing detailed geometry of the component and representative loading conditions which can be crucial to accurately simulate the three dimensionality of the propagating crack shape and further determine the associated loading cycles. In comparison to a generic model, the disadvantage of the 3D FEM is the extended runtime. One feasible way to benefit from 3D modeling is to employ it to understand the crack front evolution and growth path for the representative loading condition. Mode I stress intensity factors (KI) along the predetermined crack growth path can be generated for use in fatigue crack growth tools such as NASGRO.
In the current study, such a 3D FEM lifing process is presented using a classical bolt-nut assembly, components that are commonly used in engineering design. First, KI solutions for a fixed crack aspect ratio a/c = 1 are benchmarked against a similar solution available in NASGRO. Next, a predefined set of crack shapes and sizes are simulated using 3D FEA. A machine learning model Gaussian Process (GP) was trained to predict the KI solutions of the 3D model, which in turn was used in the crack propagation simulation to accelerate the life assessment process. Verification of the implemented procedure is done by correlating the crack growth curves predicted from GP to the results obtained directly from 3D FE crack propagation method.
Optimising the Safe Design of Pressurised Components
Authors: O’Connor Alison N. , Davies Catrin M. , Garwood Stephen J. , Hadley Isabel 
Published: November 2019

Abstract
The structural integrity of pressure vessels (PVs) is controlled by the application of various design and fabrication codes and standards. Within the European single market (ESM) design codes exist at both a European and a national level which can lead to variability in design procedures. The European standard EN 13445 has been updated several times to modify the design curves based on analytical modelling of high strength materials. The design curves in EN 13445 now differ significantly from those presented in the British national code that preceded it, namely PD 5500. As a result higher minimum Charpy test temperatures (T27J) are found using the EN 13445 procedure in comparison to those derived using the PD 5500 procedure. While the PD 5500 design curves have been validated experimentally it is generally accepted that they are overly conservative. This inherent conservatism in PD 5500 may account for some of the differences in the minimum Charpy test temperature, the analytical model used to generate the EN 13445 design curves however was validated with data from high strength steels only (σy ≥ 420 MPa). It is not clear that the results can be applied directly to low/medium strength materials. This work identifies some of the disparities between the EN 13445 and PD 5500 procedures, for low temperature applications. A programme of work, at Imperial College London, is described. This programme of work, currently underway, is aimed at addressing concerns about the robustness of the updated EN 13445 design curves, especially for lower-strength steels in the as-welded condition.
Seismic Test Results of Air-Operated Valve Actuators for Nuclear Power Plants (Air-Operated Butterfly Valve (Direct-Coupled Type))
Authors: Matsubara Yoshinao , Tsutsumi Yoshitaka , Nishino Koji , Kojima Nobuo , Ito Yasuyuki , Kubota Ryo , Suzuki Shigeki 
Published: November 2019

Abstract
The functional requirements of air-operated valves provided in nuclear power plants during an earthquake have been previously evaluated via seismic tests and so forth; however, since the response acceleration has increased in line with a recent reassessment of standard earthquake ground motions, it is necessary to evaluate functional maintenance with respect to high acceleration. It is also necessary to determine practical functionality from the viewpoint of equipment fragility in seismic Probability Risk Assessment (PRA) Here, we used a resonant shaking table (see Ref. [1]) in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels that have been unachievable until now. From the results of seismic tests on air-operated valve actuators, the operability of active components used with an existing design was confirmed to be more than 15 × 9.8 m/s2 (horizontal directions (X and Y)) and more than 20 × 9.8 m/s2 (vertical direction (Z)).