bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevated Temperature Cyclic Service Evaluation Based on Elastic-Perfectly Plastic Analysis and Integrated Creep-Fatigue Damage
Authors: Sham T.-L. (Sam) , Jetter Robert I. , Wang Yanli 
Published: December 2016

The goal of the Elastic-Perfectly Plastic (EPP) combined integrated creep-fatigue damage evaluation approach is to incorporate a Simplified Model Test (SMT) data based approach for creep-fatigue damage evaluation into the EPP methodology to avoid the separate evaluation of creep and fatigue damage and eliminate the requirement for stress classification in current methods; thus greatly simplifying evaluation of elevated temperature cyclic service.
The EPP methodology is based on the idea that creep damage and strain accumulation can be bounded by a properly chosen “pseudo” yield strength used in an elastic-perfectly plastic analysis, thus avoiding the need for stress classification. The original SMT approach is based on the use of elastic analysis. The experimental data, cycles to failure, is correlated using the elastically calculated strain range in the test specimen and the corresponding component strain is also calculated elastically. The advantage of this approach is that it is no longer necessary to use the damage interaction, or D-diagram, because the damage due to the combined effects of creep and fatigue are accounted in the test data by means of a specimen that is designed to replicate or bound the stress and strain redistribution that occurs in actual components when loaded in the creep regime.
The reference approach to combining the two methodologies and the corresponding uncertainties and validation plans are presented. Results from recent key feature tests are discussed to illustrate the applicability of the EPP methodology and the behavior of materials at elevated temperature when undergoing stress and strain redistribution due to plasticity and creep.
Elbow Flexibility Factor Calculations: An Update
Authors: Seipp Trevor G. , Mendoza Gonzalo 
Published: December 2016

Widely cited across industry, earlier work by Rodabaugh and Moore, as well as Rodabaugh, Iskander and Moore described the equations to be used during experimental or finite element analysis studies into the flexibility of elbows. The original work was done to determine the flexibility factors commonly used in the piping Codes.
However, these equations were only applicable to 45°, 90°, and 180° elbows with equal length of attached pipe. Recently, the authors had need to calculate the flexibility factors for elbows with non-equal lengths of attached piping and angles different from 45°, 90°, or 180°. This paper presents the expanded set, and hence general case, for the elbow flexibility factors.
Structural Integrity Assessment of Doel 3 and Tihange 2 RPVs Affected by Hydrogen Flakes: Methodology and Results
Authors: Lacroix Valéry , Dulieu Pierre 
Published: December 2016

During the 2012 outage at Doel 3 and Tihange 2 Nuclear Power Plants, a large number of quasi-laminar indications were detected in the reactor pressure vessels, mainly in the lower and upper core shells. The observed indications could subsequently be attributed to hydrogen flaking induced during the component manufacturing process.
As a consequence, both units remained core unloaded pending the elaboration of an extensive Safety Case demonstrating that they can be safely operated.
The Structural Integrity Assessment of the RPVs, through the Flaw Acceptability Analysis, aimed at demonstrating that the identified indications do not jeopardize the integrity of the reactor vessel in all operating modes, transients and accident conditions.
This demonstration, presented in this paper, has been done on the basis of a specific innovative methodology inspired by the ASME XI procedure but adapted to the nature and number of indications found in the Doel 3 and Tihange 2 RPVs.
Study on Effects of Non-Isothermal Condition and Strain Holding on Environmentally Assisted Fatigue in PWR Primary Water Environment
Authors: Asada Seiji , Fukuta Yuichi , Ahluwalia Kawaljit , Steininger David 
Published: December 2016

To understand the fatigue behavior of austenitic stainless steels in a simulated PWR primary water environment, the patterns were studied. Austenitic stainless steel Type 316 plate was used as the test material.
Regarding non-isothermal testing: isothermal and non-isothermal fatigue tests were carried out for several patterns of temperature change and strain rate change. Typically, fatigue lives for non-isothermal tests with an out-of-phase strain change pattern were longer than those for isothermal tests.
Regarding strain holding testing: multiple groups of strain range cycles were separated by a long hold time and several test cases were carried out. Testing shows there is little difference in fatigue life for strain holding tests with high strain amplitude.
Fundamental Study on Energy Necessary for Tensile Failure
Authors: Minagawa Keisuke , Fujita Satoshi 
Published: December 2016

Although, a part of damage of mechanical structures by actual seismic events is caused by cumulative damage, their seismic design is generally carried out by using momentary force or stress, because force and stress are calculated easily. Therefore, damage indicating parameters that can evaluate cumulative damage is necessary, and authors have focused on energy as the parameter. The energy can evaluate fatigue failure because the energy is derived from an integral of a product of force and deformation. In our previous paper, vibration and loading experiments were conducted, and the energy necessary for fatigue failure was reported. However the processes to clarify the energy necessary for failure by fatigue experiments take a long time. The processes will be shortened if the energy is clarified by tensile tests.
This paper deals with the energy necessary for tensile failure. In this paper, tensile tests were carried out, and energy necessary for tensile failure was derived. The tensile tests were conducted with various tensile speeds. As a result, more energy is needed when tensile speed is slow. This relationship is same as the relationship confirmed by vibration and loading experiments in our previous papers.
Bulging Patterns of Coke Drums
Authors: Samman Mahmod 
Published: December 2016

One of the most common defects in coke drums is bulging, which is a non-uniform radial growth of the shell. Bulging often leads to cracks that occasionally result in leaks and fires. Drum bulging and cracking often cause unplanned outages, costly repairs, and premature replacement.
Bulging is commonly treated as a single phenomenon that is caused by one failure mechanism. In this study, we examine this assumption using a database of one hundred and eighty four laser scans obtained from operational coke drums that vary in location, metallurgy, age, size, and wall thickness. Based on the study, we identified nine types of bulges and related them to loading mechanisms, design features, operating practices, and fabrication processes that likely contribute to their formation. This new understanding of bulging types and causes should help design, fabricate, and operate coke drums informed manner.
Failure Analysis Prediction Versus Industry Failure Experience of Air Operated Valves in the Nuclear Industry
Authors: Ezekoye L. Ike 
Published: December 2016

Safety related valves in the nuclear industry are designed to meet the requirements of the design specifications for the systems in which they are to be installed. In developing valve specifications, systems and valve engineers collaborate to craft the essential requirements needed to support the procurement of the valves that meet the design requirements, and thereby provide reliable service during plant life. The specification requirements, together with the ASME Boiler and Pressure Vessel Code and Standards, provide a strong basis for assuring both structural integrity and functionality of the valve assemblies.
The functional requirements cover the duties of the valves. As these valves are safety related, they are generally subjected to preoperational testing and possibly additional qualification testing during manufacture, to ensure that the valves can perform their safety related functions in service. The nuclear experience of engineered products such as valves shows that considerable amount of analysis and documentation of component stresses are performed to ensure compliance with the ASME code and specification requirements.
The ASME Code requirements, together with the normal controls applied during manufacture of safety related valves, enhance the reliability of the valves. However, valve failures still occur during plant operation. In this paper, the failures of air operated valves (AOVs) used in nuclear applications were reviewed and the data compared against the failures predicted by valve suppliers based on weak link analysis of the valves. The study shows that there are significant differences between what the suppliers consider structurally likely to fail, what the purchaser expects to fail, and what really fails from field experience. The study shows that field failures are complex. They can be initiated by many factors, most of which are not obvious and cannot be controlled by the valve designer. The complexity of field failures of air operated valves is discussed in this paper.
Emergency Core Cooling System Sump Strainer Fibre Bypass Testing and Measurement
Authors: Cheng Qingwu , Adams Harry , Yetisir Metin 
Published: December 2016

The potential of losing post-Loss Of Coolant Accident (LOCA) recirculation capability due to debris blockage of Emergency Core Cooling (ECC) strainers resulted in early replacements of ECC strainers in most nuclear power plants. To validate the performance of ECC strainers, extensive testing representing plant conditions is required. Such testing programs include thin-bed and full debris load pressure drop tests, fibre bypass tests and chemical effects tests. Multiple testing loops and state-of-the-art analysis techniques have provided in-depth understanding of sump strainer performance and the effect of chemical precipitation on debris bed head loss.
ECC strainers typically use perforated plates as filtering surfaces with 1.6 to 2.5 mm holes and 35 to 40% open area, allowing some particulates and fibres to pass through the strainer filtering surfaces. Recently, the bypassed fibrous debris has been identified as a potential safety concern due to its possible deposition in the reactor core and blocking of flow into fuel assemblies. In some cases, the amount of fibre that is specified as allowed to enter a reactor core is only 15 g per fuel assembly for pressurized water reactors. Characterization and quantification of bypassed fibre debris for nuclear power plants are needed to address regulatory requirements. Testing methodology and analysis techniques to address regulatory requirements and concerns are presented in this paper. In particular, a newly developed technique is presented to address debris bypass quantification.
Undertaking Bolted Joint Integrity Management: Getting to Zero Leaks Quickly and Effectively
Authors: Kaye Alwyn 
Published: December 2016

Leaks can and are being eliminated in a wide array of industries. There is a sweeping change across all the oil and gas, chemical and petrochemical and many related industries and businesses that use pressure equipment. This reflects social change and ever increasing demands for safe and reliable pressure equipment performance. No longer are leaks considered acceptable or the normal course of business. Codes, standards and specifications globally are changing and improving to reflect the need for improved performance. The implementation by individuals and organisations to follow this important drive to zero leaks has been hindered by fragmented guidance and misunderstanding of the plethora of options presented in the marketplace.
In industries that need to demonstrate performance, reliability and compliance, the need to create the structure and platform to make this successful has never been more pressing than it is now. Transformation of plant and equipment from normalized deviance and tolerance of leaks and failures to improved reliability is not only possible but essential in a world of resolve to cost containment and environmental protection.
This paper demonstrates the viability and importance of this change in philosophy followed by action. Examples are provided of the methodology of review and analysis through calculation followed by application. These must come together with basic plant operation in a comprehensive program of changed values and beliefs in order to be successful in the outcome. How to put it all together, is discussed and described. The paper authenticates the issues and describes the approaches needed by using case studies to demonstrate the principles and techniques needed to achieve success in implementation. It is understood that some minor modifications based on end user situations and needs may require adaptation or adjustment of some details. However the principles outlined are in keeping with and closely follow the intent and adherence to the European Standards EN-1591 and ASME Post-Construction Committee ASME PCC-1 “Guidelines for Pressure Boundary Bolted Joint Assembly”. [1,2]
Validation of FE Analysis Using a Test to Destruction Experiment for a Vessel Post Weld Heat Treatment Stand
Authors: Slee Adam J. , Stevenson Alan , Pellereau Ben , Holbourn John , Wright Keith 
Published: December 2016

This paper details the methodology of validating a furnace heat treatment stand subjected to elevated temperatures using Finite Element Analysis (FEA). An initial heat treatment stand was designed for use with a superfluous vessel, which was then analysed and validated with a tested to destruction experiment. A revised design of heat treatment stand was then developed for Post Weld Heat Treatment (PWHT) of an actual vessel, supported by the validated analysis methodology.
A 3D model of each stand was created in Abaqus using shell elements for the beam and plate sections, and spring elements for bolts. This analysis incorporated a full contact model to correctly capture the flexural characteristics of the individual components during loading of the stand. An elastic-perfectly-plastic Limit Load Analysis (LLA) was initially used to determine the expected plastic collapse load for both designs of stand at a range of temperatures. This was followed by a buckling analysis to capture how susceptible the stand was to elastic structural instability. In order to determine the sensitivity of the structures to buckling, initial elastic imperfections were seeded into a post buckling LLA; other sensitivity studies included centre of gravity offset and consideration of creep.
The test to destruction of the stand has provided validation for the analysis methodology. The analysis of the revised design has shown acceptable margin exists at PWHT temperatures.
A Systematic Approach to Re-Using of Used or Out-of-Service Static Equipment
Authors: Ebrahimi Kaveh 
Published: December 2016

The constant uncertainty within the hydrocarbon production and refining market coupled with the continued pressure to reduce greenhouse gas emissions and costs is increasing the need for operators of petroleum facilities to seek cost-effective ways of utilizing used or out-of-service equipment instead of installing new equipment. As an example, there may be equipment in parts of a refinery that have been out of service for a while, which the operator or end user would like to use in similar applications in the same refinery or other plants elsewhere.
Once an operator decides to look at the possibility of re-using used or out-of-service equipment, a few important steps need to be taken to determine whether the equipment is still operable and suitable for its new intended service. As inspection, moving or relocating of major equipment within operating plants is usually possible only during planned turnarounds, the correct identification of necessary steps, prioritizing of tasks, and precise planning and coordination of activities to evaluate the condition of used or out-of-service equipment are critical to meet the usual tight deadlines of the decision making process.
This article is structured primarily as an attempt to assist the organizations in charge of evaluation of used or out-of-service equipment to identify and plan the necessary steps in order to determine their suitability for their new intended service. Many of the issues discussed here can be also applied to any life extension evaluation program, and therefore throughout this report the term out-of-service is interchangeable with ‘used’ equipment. The focus of this article is mainly static equipment as re-using of machinery or rotating equipment would require a rather different approach [1].
Two case studies included at the end of this report demonstrate the benefits of adopting a systematic approach in evaluating used equipment.
Criteria for Selecting Materials to be Used for Hydrogen Refueling Station Equipment
Authors: Kobayashi Hideo , Yamada Toshihiro , Kobayashi Hiroshi , Matsuoka Saburo 
Published: December 2016

In this research paper, the focus is on SUS316 and SUS316L, types of austenitic stainless steel, as materials to be used for hydrogen refueling station (HRS) equipment from which hydrogen will be filled into 70 MPa onboard containers. Data on its characteristics in high-pressure-hydrogen environments, as well as methods of quantitative evaluation, were examined. On the basis of data, criteria for selecting materials and the standards to be used for HRS equipment were established.
The results indicate that the temperature ranges in which SUS316 and SUS316L can be used for HRS equipment with a hydrogen pressure of ≤82 MPa are as follows.
If the actual reduction of area of 75% is ensured, SUS316 and SUS316L can be used in the temperature ranges between −45 and 250 °C for a Ni equivalent of ≥28.5%, between −10 and 250 °C for a Ni equivalent of ≥27.4%, and between 20 and 250 °C for a Ni equivalent of ≥26.3%.
Allowable Piping Imposed Nozzle Loads on Pumps of Large Diameter Nozzles
Authors: Shitolé Bhaskar Dattatray 
Published: December 2016

Piping imposed loads are external forces and moments acting on pump suction and discharge nozzles. API 610 2010, 11th Edition, Table 5, provides a basis for nozzle sizes DN 50 to DN 400 for external forces and moments on pump nozzles. There is a frequent need in the industry for pumps of larger volumetric flow rates to have nozzle sizes larger than DN 400. The fast-track requirements of a project schedule needs a realistic and quick methodology for the pump manufacturer and piping stress engineer to have a basis for calculating external forces and moments imposed on nozzle sizes larger than DN 400.
This paper provides a methodology for determining forces and moments on pump nozzle sizes larger than DN 400. The methodology is based on the practical aspect of the most important property of pipe, which influences the quantity of force and moment it can impose.
Creep Life Assessment of High Temperature Advanced Ultrasupercritical (AUSC) Conceptual Boiler Thick-Walled Pressure Components Using Continuum Damage Mechanics Approach
Authors: Ganta B. Reddy , Soare Monica , Shen Chen 
Published: December 2016

Several nickel-based superalloys have been tested for high temperature applications for use in advanced ultra-supercritical (AUSC) fossil-fired power plants through laboratory and steam loops during the last several years. These materials include Inconel 740H and Haynes 282 which are found to have superior creep strength properties and be appropriate for use in the critical high pressure and high temperature (1400°F) AUSC boiler pressure parts such as superheater outlet header. While these materials have been extensively tested for their creep properties in laboratory test specimens, a real life design application with creep constitutive models is very limited.
In this paper, development of a microstructure sensitive continuum damage mechanics (CDM) creep model for Haynes 282 base material that covers a wide range of stress levels and temperatures suitable for AUSC boiler design applications is described. Various creep mechanisms including diffusion and dislocation phenomena are included. This base material CDM model is then applied for a typical thick-walled high temperature header component and creep life assessment for the design life of the component is estimated. This analysis along with weldments and their creep properties still under development are considered crucial for identification of high creep damage regions in the component as well as proper design life assessment of the pressure parts.
Chronic Rhinosinusitis and the Evolving Understanding of Microbial Ecology in Chronic Inflammatory Mucosal Disease
Authors: Hoggard Michael , Wagner Mackenzie Brett , Jain Ravi , Taylor Michael W. , Biswas Kristi , Douglas Richard G. 
Published: December 2016

SUMMARY
Chronic rhinosinusitis (CRS) encompasses a heterogeneous group of debilitating chronic inflammatory sinonasal diseases. Despite considerable research, the etiology of CRS remains poorly understood, and debate on potential roles of microbial communities is unresolved. Modern culture-independent (molecular) techniques have vastly improved our understanding of the microbiology of the human body. Recent studies that better capture the full complexity of the microbial communities associated with CRS reintroduce the possible importance of the microbiota either as a direct driver of disease or as being potentially involved in its exacerbation. This review presents a comprehensive discussion of the current understanding of bacterial, fungal, and viral associations with CRS, with a specific focus on the transition to the new perspective offered in recent years by modern technology in microbiological research. Clinical implications of this new perspective, including the role of antimicrobials, are discussed in depth. While principally framed within the context of CRS, this discussion also provides an analogue for reframing our understanding of many similarly complex and poorly understood chronic inflammatory diseases for which roles of microbes have been suggested but specific mechanisms of disease remain unclear. Finally, further technological advancements on the horizon, and current pressing questions for CRS microbiological research, are considered.