bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Integrity Evaluation of 3D Printed Graphene-Reinforced PLA Notched Plates Using Failure Assessment Diagrams
Authors: Cicero Sergio , Arrieta Sergio , Sanchez Marcos 
Published: November 2024

Abstract
Failure Assessment Diagrams (FADs) constitute a well-known structural integrity evaluation tool that allows structural components containing crack-like defects to be assessed through a simultaneous analysis of fracture and plastic-collapse processes. FADs are included in the most recognized structural integrity assessment procedures/standards, such as BS7910 and API 579/ASME FFS-1, and their use is generally limited to metallic components containing crack-like defects.
On the other hand, 3D printed composites, and particularly those obtained through FFF (Fused Filament Fabrication), are assuming structural responsibilities beyond their most extended use as prototyping materials. The resulting structural components may contain notch-type defects (e.g., grooves, corners, holes, etc.) that determine their corresponding structural integrity. Thus, it is necessary to define structural integrity assessment criteria for this kind of materials when containing any kind of stress risers, beyond crack-like defects.
This work justifies the use of BS7910 Level 1 FAD, coupled with a notch correction derived from the Theory of Critical Distances (TCD), to analyze graphene-reinforced PLA plates subjected to pure tensile loading conditions and containing notches. The results reveal that the assessment points representing the plates at failure are located within the FAD area corresponding to unsafe conditions, providing conservative evaluations with moderate safety margins.
Pretest Modeling a Spent Nuclear Fuel Seismic Shake Test
Authors: Klymyshyn Nicholas , Kadooka Kevin , Barrett Nathan , Spitz Casey 
Published: November 2024

Abstract
The U.S. Department of Energy Spent Fuel and Waste Science and Technology (SFWST) program is planning to conduct a series of full-scale shake table tests to simulate hypothetical earthquake conditions and record the response of surrogate spent nuclear fuel (SNF) assemblies in a dry canister storage system mockup. The shake table motions will represent a range of hypothetical earthquake conditions at hypothetical locations in the continental U.S. to generally define the range of mechanical loads that SNF can be expected to experience during extended dry storage periods. This paper describes the pretest predictions made with LS-DYNA models of the mockup storage systems.
The test will use two dry storage system configurations, a mockup vertical concrete cask (VCC) and a mockup horizontal storage module (HSM). The test will use a production-quality canister and basket. Within the canister will be four instrumented fuel assemblies with fuel rods containing surrogate mass and 28 instrumented dummy assemblies that are intended to match the mass and outer dimension of a fuel assembly. The finite element models include models of the VCC and HSM on the shake table to calculate the system level dynamic responses and separate single fuel assembly models to calculate stress and strain in fuel assembly components. Both types of models include nonlinear behavior like rod-to-rod contact and the ability for VCC’s to rock and slide.
This paper presents the expected response of the VCC, HSM, and fuel assemblies to the shake table testing that is planned to start in April of 2024. The earthquake conditions represent seismic hazards in the 2,000-to-20,000-year return period range. The test data is expected to confirm the expectation based on the presented analyses that fuel rod cladding will remain intact, fuel assembly structural components like guide tubes will remain intact, and no significant VCC sliding or tipping will occur in the range of conditions to be tested with the shake table.
NUCOBAM Project, Nuclear Components Based on Additive Manufacturing
Authors: Leopold Gaëlle , Bourgeois Myriam 
Published: November 2024

Abstract
NUCOBAM project aims at developing the qualification process and providing the evaluation of the in-service behavior allowing the use of Additively Manufactured (AM) components in a nuclear installation. Once qualified, the use of AM will allow nuclear industry to (1) tackle component obsolescence challenges and (2) manufacture and operate new components with optimized design in order to increase reactor efficiency and safety. To make this ambition a success, NUCOBAM will conduct the required studies to implement AM process in nuclear design codes and standards to produce nuclear reactor components.
The first part consists in characterization of the materials manufactured by Laser Power Bed Fusion (L-PBF) process in order to establish a qualification and codification methodology. The second part is dedicated to the evaluation of AM material behavior in-service, especially regarding the main degradation mechanisms that occur in LWR (thermal ageing, irradiation, ...). Materials are manufactured and some of them are then submitted to post-treatment (heat treatment or high isostatic pressure). Results are analysed and compared with existing approved manufacturing processes by design codes. This work will lead to evaluate and to deduce the main parameters required for specification.
The consortium thus involves electricity utilities, operating nuclear assets, component manufactures, design owners, public service experts in nuclear and radiation risks as well as research and competence centres involved in mechanical assessment, metal powder qualification, metallurgical characterization, materials irradiations capabilities and nuclear power research.
Study of Crack Initiation and Fracture Toughness Evaluation in JIC Testing of Linepipe Steel Under Gaseous Hydrogen Environment
Authors: Nishihara Yoshihiro , Inoue Ryuichi , Okano Hiroshi , Sakimoto Takahiro 
Published: November 2024

Abstract
Hydrogen is one of the promising energy carrier for achieving the carbon neutral society. The pipeline system is positioned as a major infrastructure indispensable for mass transportation of gaseous hydrogen. Material degradation in hydrogen embrittlement is considered in the hydrogen pipeline code ASME B31.12. The fracture toughness is required to be obtained by the test based on ASME BPVC sec.8 div.3. However, most of the line pipes have low strength and high toughness, so the evaluation by the above method is not suitable from the viewpoint of specimen size and mechanical constraint. Therefore, evaluation of fracture toughness by elastic-plastic fracture toughness test has become common. On the other hand, current standards for elastic-plastic fracture toughness tests, such as ASTM E1820, are based on the premise of conducting tests under atmospheric conditions, and do not consider ductility reduction and crack initiation mechanism changes caused by hydrogen entering steel under hydrogen gas conditions. In this study, the effects of hydrogen and test conditions on the crack initiation limit in JIC tests were investigated, and a method for evaluating the toughness value based on the fracture behavior of specimens under hydrogen gas environment was examined. Focusing on the fact that the stretched zone width (SZW) which is formed at the leading edge of a fatigue pre crack as a trace of plastic deformation just before a stable crack is initiated, in hydrogen gas was shorter than in air, when the fracture toughness (JSZ) obtained from SZW was defined as a value corresponding to the fracture phenomenon, the value obtained from the J-R curve according to the standard was overestimated for JSZ. In order to properly evaluate the fracture toughness value in hydrogen gas more efficiently considering the man-hour required for SZW measurement by fracture surface analysis, a method using J-R curve and blunting straight line prepared in the region of short crack growth was proposed.
Long-Term Creep Strength Evaluation of Welded Joint of ASME Grade 91 Type Steel
Authors: Yaguchi Masatsugu 
Published: November 2024

Abstract
Creep rupture data of welded joints of ASME Grade 91 type steel were collected by the Assessment Committee on Creep Data of High Chromium Steels, which consists of the Federation of Electric Power Companies of Japan, material producers, power plant manufacturers, and institutes in Japan, and the creep rupture life curve of the material was evaluated using the latest dataset to examine the validity of the long-term creep rupture life curves determined by the committee in 2015. The evaluation of the welded joints of Grade 91 type steel is the fourth time in Japan, as similar studies were conducted in 2004, 2010, and 2015. Creep rupture strength was re-evaluated with emphasis on the long-term creep rupture data obtained after the 2015 study, in which the rupture time in new data was up to about 100,000 h. It was found that the evaluation formula for the welded joints of Grade 91 type steel proposed in 2015 can be used for the appropriate evaluation of the new long-term data of the material. The creep curves calculated using the 2015 evaluation formula were also compared with the results of creep strength analysis under actual service conditions obtained using creep data of a long-term used material, and it was shown that they were in agreement with reasonable precision. Therefore, it was suggested that the 2015 evaluation formula for the welded joints of Grade 91 type steel is valid in the long-term region; thus, there is no need to revise it.
Mode I and Mode II Stress Intensity Factors for a Slanted-Edge-Crack Affected by an Adjacent Horizontal Crack Under Remote Tension
Authors: Levy Cesar , Perl Mordechai , Ma Qin 
Published: November 2024

Abstract
Fracture mechanics has been used in Fitness-for-Service assessments of structures containing cracks. The stress intensity factors (SIFs) at the crack tip are the key information in assessing the remaining service life of a cracked component. Extensive studies have been carried out on the mutual influence of adjacent parallel cracks. However, to date no solutions are available for non-parallel cracks. In the present analysis mode I (KI) and Mode II (KII) SIFs of a slanted-edge-crack affected by an adjacent non-parallel horizontal crack are obtained. KI and KII are evaluated for a wide range of the slanted edge crack angle β = 0° to 75°, for various normalized horizontal (S/a2 = −0.4 to 2) and vertical (H/a2 = 0.4) separation distances and for several crack lengths. The problem is solved using a 2-D, plane strain, finite element model, which was successfully validated against presently available solutions. It is found that the presence of the embedded crack always amplifies KI of the edge crack while KII might be either amplified or attenuated depending on the crack configuration. Furthermore, the present results indicate that, for the purpose of Fitness-for-Service, the effective SIF at the tip of the slanted crack always increases due to the presence of the embedded crack.
Tank Bottom Settlement Evaluation
Authors: Nadarajah Chithranjan 
Published: November 2024

Abstract
Localized bottom settlement is a form of settlement on storage tank bottom which is generally made out of lap welded plates. Localized bulges, ridges or depression of the bottom plate can result in lap weld failure which could lead to a leak. Currently tank bottom settlement is evaluated using the procedures in API 653 [1]. However, this procedure tends to be conservative and there are many tanks in operation where the bottom settlement has exceeded the API 653 requirements. Generally, when the bottom settlement exceeds the API 653 criterion, the tank is evaluated on a case-by-case basis using a combination of inspection and numerical analysis to determine whether they are fit for service.
This paper examines the background to the development of the tank bottom settlement procedure in API 653 and two alternative procedures are provided which will result in higher allowable bottom settlement.
Effects of Hydrogen on Fatigue Life Properties of Cold-Rolled Metastable Austenitic Stainless Steels With Artificial Defects
Authors: Yamabe Junichiro , Hashiguchi Kento , Wada Kentaro 
Published: November 2024

Abstract
It is important to understand the effect of hydrogen on the fatigue properties of materials to ensure the safety and reliability of hydrogen components. In this study, a cold-rolled metastable austenitic stainless steel, JIS-SUS301, with a tensile strength of around 1.3 GPa was prepared and subjected to plane-bending fatigue tests in air at room temperature by using uncharged and H-charged plate specimens with a thickness of 2 mm. A drilled hole or a sharp notch was introduced at the center of the plate specimens to control crack initiation sites. The H-charged specimens were exposed to 100 MPa hydrogen gas at 270°C for 200 h. The results showed that in high-stress amplitude regimes, the fatigue life of the specimens with a drilled hole or a sharp notch was significantly degraded by hydrogen. In contrast, the fatigue limit of the specimens with a drilled hole, which was determined by the critical stress for crack initiation, was not degraded by hydrogen, or was slightly raised, while the fatigue limit of the specimens with a sharp notch, which was determined by the threshold stress for crack propagation, was not affected or was only slightly degraded by hydrogen. Although the effect of hydrogen on the fatigue limit differed between the drilled hole and sharp notch, the difference was not significant.
Pipeline Weld Radiographs Defect Detection Based on Improved YOLO V8
Authors: Ren Qingying , Dong Shaohua , Qian Weichao 
Published: November 2024

Abstract
Pipeline transportation is a crucial method for transporting oil and gas, and with the growing energy demand, the scale of oil and gas pipelines is expanding rapidly. Most of the oil and gas pipelines are joined together by welding. Weld defects often lead to significant safety accidents, making it essential to test the quality of the welds. Radiographic Testing (RT) is a widely used Non-Destructive Testing (NDT) technology. The manual inspection of weld negatives obtained by X-ray inspection is a common method for detecting weld defects, but it involves a heavy judgment workload, making it prone to misjudgment and omission. An enhanced algorithm based on YOLO V8 for identifying and localizing weld defects was proposed in this paper to address this issue. The Receptive Field Block (RFB) mechanism was introduced to enhance the network’s feature extraction ability by using different sizes of receptive fields. This approach aims to simulate the human visual system and reduce misleading image backgrounds for small object detection. The EIOU loss function, which considers the overlap area between the detection frame and the real frame, the distance from the center point, and the actual difference between the length and width of the sides, was employed to address the issue of the fuzzy definition of the aspect ratio. Meanwhile, a dataset of six types of defects, including round defects, strip defects, cracks, slag inclusion, incomplete fusion, and incomplete penetration, was established. The experimental results show that the mean average precision (mAP) of the improved YOLO V8 reaches 89.3% for six types of defects. Compared to advanced object detection algorithms like Faster R-CNN, YOLO V5, and the original YOLO V8, the improvements are 44.92%, 22.88%, and 1.4%. The method can accurately and quickly identify a wide range of pipe weld defects.
A New Stress-Intensity Factor Solution for an Internal Surface Crack in Spheres
Authors: Sobotka James C. , Lee Yi-Der , Cardinal Joseph W. , McClung R. Craig 
Published: November 2024

Abstract
This paper describes a new stress-intensity factor (SIF) solution for an internal surface crack in a sphere that expands capabilities for this common pressure vessel geometry. The SIF solution employs the weight function (WF) methodology that enables rapid calculations of SIF values. The WF methodology determines SIF values from the nonlinear stress variations extracted in the uncracked geometry, e.g., from service stresses and/or residual stresses. The current approach supports two degrees of freedom that denote the two crack tips located at the deepest location and the surface of the sphere. The geometric formulation of this solution enforces an elliptical crack front, maintains normality of the crack front with the free surface, avoids non-physical crack shapes with protruding “ears”, and supports two degrees of freedom for fatigue crack growth from an internal crack tip and a surface crack tip. The new SIF solution enables all spherical geometries with the exterior diameter greater than or equal to four times the thickness. This WF SIF solution has been combined with stress variations common for spherical pressures vessels: internal pressure on the interior surface, uniform tension on the crack plane, and bending on the crack plane. These stress variations facilitate solution usability. This work builds on earlier efforts for an external surface crack (PVP2021-61397[1]) and provides a comprehensive solution capability for spheres.
This paper provides a complete overview of this solution. We present for the first time the geometric formulation of the crack front that enables the new functionality and set the geometric limits of the solution, e.g., the maximum size and shape of the crack front. The paper discusses the bivariant WF formulation used to define the SIF solution and details the finite element (FE) analyses employed to calibrate terms in the WF formulation. A summary of verification efforts demonstrates the credibility of this solution against independent results from FE analyses. We also compare results of this new solution against independent SIFs computed by FE analyses, legacy SIF solutions, API 579, and FITNET. These comparisons indicate that the new WF solution compares favorably with results from FE analyses. Finally, we summarize the capabilities of this solution in NASGRO®.
New Evaluation Method Based on CAV for Seismic Fatigue Damage of Plant Pipeline (Applicability to General Pipelines)
Authors: Inada Fumio , Sakai Michiya , Morita Ryo , Tamura Ichiro 
Published: November 2024

Abstract
Unnecessary plant shutdowns are avoided using the cumulative absolute velocity (CAV) on the nuclear power plant’s free-field seismic instrumentation to determine operating basis earthquake in the US; however, the relationship between the CAV and damage mechanism has not yet been clarified. In a previous study, authors found that the CAV of the piping vibration response can relate to the vibration stress, using the velocity rule from the ASME standard for the Operation and Maintenance (OM) of Nuclear Power Plants. Using the velocity rule, a new evaluation method of cumulative fatigue damage can be derived as proportional to CAV of the vibration response to the 2.4th power. The feasibility of this has been confirmed only for cantilevered pipes that have a mass at the tip. In this study, the Z-bend pipeline and three-dimensional pipeline used in the JSME benchmark analysis are considered to confirm the applicability of the new method based on the velocity rule to more general pipelines. The vibration response of these general pipelines to seismic waves was calculated, and the cumulative fatigue damage was evaluated using both the new method and direct calculations. The results were in good agreement.
Study on Compatibility Assessment of Urban Natural Gas Pipeline Welded Joints Under Hydrogen Environment
Authors: Guo Songrui , He Xiang , Shao Lingxiao , Shen Xi , Hua Zhengli 
Published: November 2024

Abstract
Hydrogen, as one of the crucial carriers in achieving the green and low-carbon transition, plays a significant role in a multi-energy structure. Among the existing hydrogen transportation methods, the transportation of hydrogen in the form of hydrogen-blended natural gas through the existing urban natural gas pipeline network is an effective way to enhance transportation efficiency and substantially reduce costs. However, when hydrogen comes into contact with the metal materials of natural gas pipelines, it can lead to hydrogen embrittlement, resulting in a deterioration of the mechanical properties of the metal materials and even causing significant accidents. Notably, the welded joint area of gas pipelines is widely recognized as the vulnerable link in pipeline transportation systems because the microstructure and mechanical properties of the welded joint area differ significantly from those of the pipeline steel base material, making it the most susceptible site for hydrogen embrittlement-induced failure. In this study, using 20# steel as the research subject, specimens were taken from the vertical weld seam in its welded joint area. The slow strain rate tensile test, low cycle fatigue test and fatigue crack growth test under hydrogen environment were carried out to explore the variation of mechanical properties under different working conditions. The results demonstrate that with an increase in hydrogen content, the yield strength and tensile strength of the welded joint in 20# steel decrease slightly, resulting in a deterioration of mechanical properties. The elongation and reduction of area after fracture decrease, indicating reduced material plasticity and an intensified degree of hydrogen embrittlement. With the addition of hydrogen, the overall low cycle fatigue life of specimens decreases. The relative fatigue life for the three materials are 74.22%, 62.02%, and 46.05%, demonstrating a noticeable decline in fatigue performance. Hydrogen significantly increases the fatigue crack growth rate in the weld zone of 20# steel. At a hydrogen addition of 10vol%, the fatigue crack growth rate is already approximately 12 times higher than that in the reference environment with 0vol% hydrogen. Simultaneously, with the increase of hydrogen content, the fatigue crack growth rate and the degree of deterioration both escalate, and the deterioration indexes are all above 90 %. The research findings can be utilized to assess the compatibility of gas pipeline welded joints in a hydrogen environment.
Assessing Bulge-Induced Damage in Coke Drums to Plan Structural Weld Overlay Repairs
Authors: Araque Vivas Egler Dubin , Park Stephen Michael 
Published: November 2024

Abstract
Depending on the cycle time, design, fabrication, and operations, coke drum repairs could be required in as little as five years of operation. In the last fifteen years, use of Structural Weld Overlay (SWOL) as a repair strategy to extend the remaining life of coke drums has increased. Bulge-induced damage in the cylindrical and conical sections is one of the main reasons for SWOL repairs to be executed in vessels.
The Local Plastic Strain Indicator, abbreviated as LPSI, is used as a methodology to show two cases of how bulge-induced damage evolves and at what point SWOL repairs should be applied in coke drums. LPSI identifies and ranks bulges prone to local failures using an estimation of plastic strain calibrated against bulges that developed internal or external bulge-induced damage. The LPSI is the ratio of the plastic strain found at the analyzed point to the calibrated strain limit found at points where through-wall cracks occurred due to bulging, in a percentage form.
As the cases show, there have been many premature repairs executed because of the lack of assessment of surface damage and problems with damage have then developed at the edges of those weld overlay repairs. At the end, guidance about how strain levels and surface damage should be combined to better assess SWOL repairs areas is provided.