bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pipeline Stacked Crack Interaction Burst Pressure Analysis Using 3-D Crack Meshes
Authors: Holloman Ryan , Thorwald Greg , Turnquist Michael , Neuert Mark 
Published: November 2023

Abstract
Accurate evaluation of the remaining strength of cracklike flaws identified via pipeline inline inspection (ILI) or in-ditch non-destructive examination (NDE) is critical to ensuring continued safe operation of liquid and gas transmission pipelines. Modern pipeline ILI tools have sufficient resolution to detect longitudinally overlapping crack-like flaws that exist in the same radial plane, referred to as stacked cracks. Depending upon the crack sizes and pressure loading, stacked cracks can interact to reduce burst pressure below that of any of the individual stacked cracks.
Closely located cracks are often evaluated using interaction criteria, such as those provided by API 579-1/ASME FFS-1 Part 9 (API 579) [1], which specify how and when multiple nearby cracks can be combined into a single crack for the purpose of an integrity assessment. When applied to stacked cracks, the interaction criteria can often lead to recategorizing stacked cracks as a through-wall crack, which requires urgent response from the pipeline operator.
Here, an improved interaction criterion was developed for stacked cracks based on the results of elastic-plastic finite element analysis (FEA) models of multiple combinations of stacked crack sizes and orientations, pipe material properties, and operating stress. These improved interaction criteria provide pipeline operators with an easy-to-apply methodology to analyze stacked cracks that reduces the excess conservatism associated with legacy methods.
Bending Moment in Flange Design, Capacity, Allowable Loads and FEA Methodology
Authors: Lutkiewicz Przemyslaw 
Published: November 2023

Abstract
There are many types of flange and clamp connectors in use and described by different standards. Most of them are based on the linear elastic methodology and allowable stress concept (ASME, API flanges). More modern designs (ISO 27509 and NORSOK L-005 Compact Flanges, NORSOK U-001 subsea flanges) are based on elastic plastic principles and plastic collapse capacities. For all of them defining the tensile structural and functional limits is relatively transparent and seamless process. Often the external allowable Bending Moment load at rated Pressure is one of the most critical characteristics for subsea use and High-Pressure connections. To predict capacity and allowable Bending Moment is more complicated especially for modern flange types. In this paper author will focus and explaining already existing design methods with relation to the FEA assessment and modern connections structural and functional capability. The topic will be discussed based on the Compact Flange (ISO 27509 and NORSOK L-005) connection example and in related structural FEA long term functionality check based on DNVGL-RP-F112 recommendations (Hydrogen Induced Stress Cracking for subsea Duplex and Super Duplex material). In the presented example the focus will be on the flange itself, but the attached pipe also be included in the evaluation. The topic discussed in the paper and the conclusions are included in the FEA recommendation in the newest national NORSOK L-005 flange design code release.
The Experimental Investigation of Flow Induced Pulsations in Corrugated Flexible Pipes in Service With Supercritical Carbon Dioxide
Authors: Belfroid Stefan , González Díez Néstor , Meijer Irma , van Beek Pieter 
Published: November 2023

Abstract
Internally corrugated flexible pipes and hoses are prone to generate high amplitude tonal pressure pulsations (singing, also called FLIP). This is a common experience in flexible risers and flowline used in the offshore oil & gas industry. Models to predict the onset conditions when this singing occurs have been developed for this market. Similar flexible lines are and will be used for CO2 transport, for instance in CCS projects. The transport conditions will be mainly in the supercritical region. To verify if singing occurs in the supercritical region and if the prediction models are still valid, small scale singing experiments have been done with a 1.37m long 6mm ID hose with pure CO2 at conditions ranging from 2 to 180 bara.
Clear singing was shown to occur at all pressures with similar characteristics (Strouhal number and amplitudes) between CO2 operations as low pressure air conditions. The onset velocity could be matched based on an energy balance method and on a feedback criterion. The current tools employed for natural gas transport do need adaptions to be valid for CO2 transport calculations.
The main conclusion is that flow induced pulsations in corrugated flexibles are generated in CO2 at supercritical conditions and that when these type of flexibles are used for CO2 transport, the same screening is advised as is common for the use of flexibles for natural gas transport.
Effect of Bolt-Up Stress Level on the Strength of ASME B16.5 and B16.47 Standard Flanges
Authors: Bouzid Abdel-Hakim , Bouzid Sofiane , Benfriha Khaled 
Published: November 2023

Abstract
ASME B16.5 and B16.47 flanges are extensively used in the pressure vessels and pipping industry. The origin of their class and size is not based on the amount of initial bolt load they can carry nor the level of tightness they can achieve. Their PV rating does not give an indication on the level of stress they are subject to and little is known on their ability to withstand the bolt stress level they are subjected to during initial bolt-up and under operation. The integrity and leak tightness of ASME B16.5 and B16.47 made of SA105 material needs to be analyzed individually in order to identify the flange classes and sizes that are more vulnerable to initial bolt-up stress level.
This paper proposes the use of an accurate analytical model to appropriately address the integrity and tightness of the complex statically indeterminate weld neck standard flange connections based on the flexibility and the elastic interaction between the different joint elements. As such, the most critical standard flanges in terms of class and size will be identified in order to avoid their structural and leakage failure. The model is first tested and validated using simulations using FEM on different sizes of class 900 flanges. The study will investigate the effect of the initial bolt preload on parameters such as flange rotation and stresses in the flange, gaskets and bolts. The most critical size and class flanges and their highly stressed locations will be revealed.
Visualization of the Decomposition and Relief Process in High-Pressure Systems
Authors: Röblitz Aaron , Busch Markus 
Published: November 2023

Abstract
The prevention of decomposition plays a crucial role in polymer chemistry. Since these cannot be completely avoided, e.g., due to the formation of hotspots, a sound knowledge of the decomposition characteristics and the resulting relief process is of enormous importance. Essential parameters are the flame front velocity, the maximum pressure, and the pressure change rate, but also factors such as the flame front geometry, which has a considerable influence on the burning velocity and the relief process. Within the scope of this work, the described parameters are investigated with the aid of a view cell as a function of various variables. The influence of the ignition and relief position, the composition, and the pressure and temperature conditions are considered. Here, the focus is mainly on the conditions in a high-pressure separator, for example in the LDPE production process. By using fast-response pressure and temperature sensors and a high-speed camera, time-resolved results can be obtained that provide information about the decomposition and relief process.
Semi-Empirical Modeling of Irradiation-Induced Dimensional Change in H-451 Nuclear Graphite
Authors: Johns Steve , Windes William E. 
Published: November 2023

Abstract
Nuclear graphite has been used as a moderator material in nuclear reactor designs dating back to the first reactor to reach criticality, Chicago Pile 1, in 1942. In addition, it is anticipated to be used in the conceptual Generation four (GenIV) Molten-salt reactors (MSRs) and the High-temperature gas-cooled reactors (HTRs). The macroscopic dimensional change observed in irradiated nuclear graphite is a property change of significant importance. Largely, volumetric change provides valuable insight into the in-service lifetime of graphite components used in nuclear reactors. The dimensional change behavior varies amongst each grade of nuclear graphite due to processing techniques and the resulting microstructure. In this work, historic data for nuclear graphite H-451 is revisited. A semi-empirical methodology is proposed to describe the dimensional change behavior as a function of temperature for nuclear graphite H-451. The turnaround dose, or when there is a reversal of the dimensional change from contraction to expansion, is proposed to be a thermally activated process and thus can be described by an Arrhenius model. On the atomic scale, H-451 is sp2-bonded carbon atoms with some degree of disorder regardless of orientation. Towards that end, the activation energy is assumed to be a constant irrespective of orientation.
Flow Induced Vibration of Piping Systems
Authors: Antaki George 
Published: November 2023

Abstract
This paper provides a logical, step-by-step approach to address flow-induced vibration in piping systems and pipelines. Starting with immediate actions when significant vibration is observed, followed by root-cause determination with a description of the various sources of vibratory excitation, proceeding to monitoring techniques to monitor the hydraulics or the vibratory motions, determining the degree of severity of the monitored parameters, and providing the full range of hydraulic and structural options to reduce or eliminate the vibration. The paper addresses the existing standards and criteria for flow-induced vibration in piping systems, across industries.
INCEFA-SCALE (Increasing Safety in NPPs by Covering Gaps in Environmental Fatigue Assessment - Focusing on Gaps Between Laboratory Data and Component-Scale)
Authors: McLennan Alec , Cicero Román , Beswick Jack , Courtin Stéphan , Que Zaiqing , Cicero Sergio 
Published: November 2023

Abstract
INCEFA-SCALE is a five-year project supported by the European Commission HORIZON 2020 programme. INCEFA-SCALE kicked off in October 2020 and is the successor to the INCEFA-PLUS programme that ran from 2015 to 2020. The objective is to continue working towards advancing the ability to predict lifetimes of Nuclear Plant components when subjected to Environmentally Assisted Fatigue (EAF) loading.
Nuclear Plant operators have generally observed that the number of failure events attributable to EAF are fewer than predicted by current assessment methodologies. It is internationally recognised that a contributor to this discrepancy is the transferability of data from laboratory-scale tests to real nuclear components. This is the main knowledge gap addressed by INCEFA-SCALE. The project strategy will be (1) the development of mechanistic understanding developed through detailed examination of test specimens and data mining from large fatigue datasets, and (2) testing and analysis focussed on aspects and features of component-scale cyclic loading. The project has created tools to survey the fatigue data within JRC’s database and feed screened data into analyses. In parallel, a testing programme has been specified and is underway. The testing programme is focussed on studying the effect of variable amplitude loading, environment, surface condition, and specimen geometry on the fatigue life of stainless-steel specimens. A materials characterisation work package is investigating the effect of the test conditions on fracture surfaces and combining that analysis with a range of materials properties and test data to contribute towards an improved mechanistic understanding of EAF. An analysis work package is actively working on scientific and engineering models to inform predictions of specimen life and develop approaches to account for the conditions studied in EAF assessments. Finally, the project will deliver guidance on the use of laboratory-scale data for component-scale applications.
This paper will outline progress from the first two years of the project. Specific details relating to the testing, materials characterisation, and analysis work packages will be presented in additional papers and presentations during the INCEFA-SCALE session.
Models for Estimating the Autofrettage Pressure and Residual Stresses in Walls of Type 2 Pressure Vessels
Authors: Tang Tsz Ling “Elaine” , Sripragash Letchuman “Sri” , Narasimhachary Santosh B. , Saxena Ashok 
Published: November 2023

Abstract
Autofrettage is a manufacturing process used during fabrication of Type 2 pressure vessels designed for usage at high pressures to enhance the fatigue life. The process locks high compressive residual stresses in the vessel’s liner wall that reduce the maximum and the mean stress during service loading. To achieve a consistent residual stress profile across the wall of the vessel, the choice of autofrettage pressure is critical. Several finite element analyses runs were conducted to estimate the correct autofrettage pressure that is a function of the yield strength of the liner material, the wall thickness, and the outside diameter of the liner for a wrap thickness of 17.06 mm (48 wire layers). From the finite element analyses results, models were developed to estimate the correct autofrettage pressure and the residual stress distribution across the liner wall as a function of the yield strength of the liner material, the wall thickness, and the outside diameter of the liner.
Parametric Numerical Assessment of an Aerojet General Nucleonics Reactor Against Postulated Fire Conditions
Authors: Jyung Jae-Min , Chang Yoon-Suk 
Published: November 2023

Abstract
As a part of periodic safety review of nuclear power plants, it is required to ensure fire protection of major facilities and structures in accordance with consolidated international and national legislations. However, most of studies have been focused on huge commercial reactors and lack of information on small research or educational reactors. The objectives of this research are to implement fire hazard analyses of an aerojet general nucleonics (AGN) reactor by using two numerical softwares and to address effect of relevant parameters. Firstly, a remarkable oil fire scenario was assumed by taking into account characteristics of compartments with various fire areas, ventilation conditions, duration time, and so on. Then, thermal integrity of reactor room was evaluated by computational fluid dynamics simulation and structural integrity of the simplified AGN reactor module was checked by systematic finite element simulation. Further, contributions of each parameter and interaction among parameters were quantified, from which not only temperature histories but also von-Mises stress distributions were calculated. As results, it was proven that all the maximum stress values were lower than the corresponding allowable criterion to sustain integrity of the reactor module. Also, the duration time was determined as the most influential parameter and interaction effect between fire area and duration time were significant.
Ultra-Thick 9% Nickel Plates for Cryogenic Pressurized Equipments
Authors: Pillot Sylvain , Milek Jean-Christophe , Higelin Anne , Zuazo Ian , Loukachenko Natalia 
Published: November 2023

Abstract
9%Ni (as per ASME SA553 type I) is the reference material for the fabrication of large LNG flat bottom above ground storage tanks servicing at −163°C/−260F and industry has then a long experience with that alloy. Considering the case of pressurized applications, the situation is largely different as only few examples of using 9%Ni can be found. AISI 304L austenitic stainless steel is in that case the material of choice, despite its low strength.
On one hand, usual applications in LNG business as well as new low temperature applications linked to the Global Energy Transition could benefit of high performances coming with that alloy. Its high strength and allowable stresses — in comparison to ones on 304L — permit to significantly reduce the wall thickness of pressure vessels while keeping an excellent level of toughness and hence of safety.
But on the other hand, experience with thick sections is very scarce and pressurized equipments fabrication require significantly thicker products than ones encountered in low pressure above ground flat bottom storage tanks. Consequently, demonstration of the industrial feasibility of such equipments needed to be done.
The present paper aims at summarizing recent developments made to produce ultra-thick plates (up to 100mm/4inches thick) and properties achieved on such thick products. Base materials as well as welded joints have been extensively studied, in various thermal states able to replicate all industrial configurations required by customers involved in the fabrication of large cryogenic pressurized vessels. Materials properties after PWHT were measured, as some pressure vessel construction codes may require such treatments after welding or forming operations, depending on design conditions and on considered product thickness. Finally, heterogenous welds between 9%Ni and 304L austenitic stainless steel have been tested with the aim of enabling the use of conventional pressure vessel sub-components (such as nozzles, piping, flanges) with 9%Ni pressure vessels.
Performances down to −196°C/−320F have been addressed by the various tests made during the study. All results achieved are satisfactory and it is demonstrated to be safe to use 9%Ni for the fabrication of large pressure vessels.
A Simplified Yet Effective Approach for Calculating Permissible Loads on Bracket Supports Attached to Cylindrical Shells
Authors: Manjrekar Vivek , Stokes Neville , Choi Junho 
Published: November 2023

Abstract
The analysis of bracket loads on tanks and vessels from pipe supports and other attachments is a frequently encountered problem for design engineers. A careful evaluation of stresses due to discontinuity between the bracket attachment and shell is required. One of the most commonly used methods for evaluation of external loads on cylindrical shells is WRC Bulletin 107/537, however this method is limited to maximum radius-to-thickness ratio (R/T) of 300. For thin-walled shells, the R/T ratio can be much higher.
In this research work, the stresses in cylindrical shell at bracket attachment are studied using finite element method. Cylinders with varying R/T ratios and brackets with different configurations are considered. Based on the study results, a simplified method is proposed for calculating the allowable loads on bracket attached to cylindrical shell of tanks and vessels. The non-dimensional coefficients are provided to determine the limiting forces and moments in each direction. These coefficients take into consideration the hoop stresses due to product head and internal pressure. Correction factor to account for excess thickness in shell plate is included. For checking the combined effects of forces and moments in all directions, interaction equations are provided. Lastly, sample example is presented to demonstrate the application of the proposed method.
A Study of Stress Relaxation Cracking Mechanism in a 347H Steel Pipe-Shoe Weldment After Five-Year Service
Authors: Wang Yiyu , Yang Yi , Gao Yanfei , Penso Jorge , Feng Zhili 
Published: November 2023

Abstract
347H stainless steel has been widely used for piping, furnace tubes, pressure vessels and other pressure boundary components in oil refining plants because of its excellent high-temperature strength and high oxidation and sulfidation resistance. However, cracking failures in 347H steel weldments could occasionally occur and significantly shorten lifetimes of those welded heater components. In this work, a comprehensive metallurgical analysis was conducted on a cracked 347H steel pipe-shoe weldment after only about 5-year service at a petroleum refinery. Premature cracking mechanisms of this pipe-shoe weld were studied in detail by correlating multiple factors, including service conditions, weld configuration, chemical compositions, and microstructure degradations. Microstructural characteristics of different regions in the weld, including fusion zone, heat affected zone, and base metal, were examined using multi-scale microscopic techniques. The results show the cracks initiated at the fusion boundary in the weld toe and propagated towards the heat affected zone and base metal in an intergranular manner. The cracks grew via connecting grain boundary cavities formed during service. Insufficient precipitation strengthening from M23C6, and MX assisted nucleation and growth of cavities along grain boundaries was observed. Ferrite formation along grain boundary induced a high localized strain along grain boundaries, which also favored crack propagation. Due the thermal gradient during service, the microstructure degradation (cavities) along the pipe wall thickness direction was not uniform, the region near the outer diameter has more cavities than that of the inner diameter wall. It is suspected that the high stresses in the weld toe region caused by the deviation from component’s original design and rotational forces on the weld resulting from the weld configuration, were the main external driving force responsible for this observed early failure. A combination of stress relaxation cracking, thermal stresses, and microstructure degradation was likely the main culprit for this premature cracking issue.
Pipeline Steel Tabular DA/DN Curves With Validations, & Potential Hydrogen Transport Application
Authors: Harter James A. , Lamborn Lyndon 
Published: November 2023

Abstract
Fitting da/dN data with closed-form equations can introduce unwanted error into a crack growth model. Using a tabular look-up approach which remains strictly data-driven has historically found utility in aerospace, and could become equally useful in fitting emerging da/dN results for hydrogen-charged pipeline steels. The objectives of this paper are to document the process for tabular datafitting, illustrate its functionality for pipeline steels, present validation work completed, and illustrate a sample application to pipe steels in a diffusible hydrogen environment.
The tabular crack growth rate model is based on the Walker equation applied on a point-by-point basis at selected crack growth rates. This paper will review the historical basis for the method, provide details of the development and considerations for pipeline steel curves, discuss important modelling issues, and validation work completed to date on in-service onshore pipeline incidents.
The tabular da/dN method applied to hydrogen-charged pipe steels is compared and contrasted to a proposed piecewise equation-based method. Life comparisons for the two methods are conducted for some actual gas and liquid pipeline operating cycling severities. Sensivity to ancillary growth influences, such as superposition of residual stress fields and time dependency are illustrated. A unified stress corrosion crack life analysis with both mechanical and time dependent growth in a hydrogen-charged pipe steel is illustrated. The utility of tabular full range da/dN curves in the aerospace community is summarized to compare and contrast potential utility in the pipeline industry.