bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Welding and Constraint Conditions on the Welding Residual Stress and Hardness of Type 316 Stainless Steel Pipe
Authors: Li Suo , Yamaguchi Yoshihito , Katsuyama Jinya , Li Yinsheng 
Published: November 2024

Abstract
Flaws due to stress corrosion cracking (SCC) were recently detected in welded joints of austenitic stainless steel piping lines in pressurized water reactors. Welding-induced high hardness and tensile residual stress are known as one of the main factors affecting SCC. In this work, thermal-elastic-plastic coupled three-dimensional finite element analyses were performed to investigate the distributions of welding residual stress and hardness in butt-welded joints of Type 316 stainless steel. Different heat inputs were applied to the pipe welds, including normal heat input, high heat input and very high heat input. Two different axial constraints were considered for the welded joints, i.e., both ends free or clamped. Simulation results were compared with experimental data such as welding thermal cycle, axial shrinkage, and residual stress for validation. The effects of heat input and constraint condition on the welding residual stress and hardness were discussed in detail. The predicted results show that there are high hoop residual stress and high hardness in the 13-pass welded joint with normal heat inputs, and high axial residual stress in the 4-pass welded joint with very high heat inputs. The axial welding residual stress and hardness can be reduced by mitigating the axial constraint in the welded joint.
Life Assessment of Metals Used in Fusion Using R5 and RCC-MRx
Authors: Belrhiti Younes , Hamelin Cory , Knowles David , Mostafavi Mahmoud 
Published: November 2024

Abstract
In the European DEMOnstration Fusion Power Plant (DEMO) fusion reactor, in-vessel components face significant thermomechanical loads. They can experience severe damage due to high thermal load cycles, coupled with severe electromagnetic loading and unprecedented levels of irradiation damage. Cooling fluids are used to extract the heat to reduce operating temperatures and for energy production. Other elements, like the shielding liner and reflector plate supports, may also experience severe creep-fatigue and irradiation damage.
To assess the high-temperature structural integrity of such components, procedures in R5 and RCC-MRx are used to assess creep-fatigue, whereby fatigue is assumed from pulsed reactor operation and creep from sustained load at high temperatures. This project aims to conduct a creep-fatigue assessment of a representative joint, tungsten-to-tungsten via copper brazing (W-Cu). However, due to a lack of data on such fusion-specific joints, two more conventional joints are studied: a 316L similar metal weld; and a 316L-to-10CrMo9-10 dissimilar metal weld.
Methodologies used for creep-fatigue assessments within R5 and RCC-MRx are detailed and compared, then applied to each material using the appropriate materials data. The two procedures share similar underlying approaches however, some subtle differences may become important within an assessment.
Assessment of Circumferential Crack-Like Flaws in Piping Accounting for Partial Compressive Zone Using Contact Elements
Authors: Dulieu Pierre , Van Ende Antoine , Lacroix Valéry 
Published: November 2024

Abstract
When a circumferential surface crack-like flaw is detected in a pipe subjected to a bending load, it may be partially located in a compressive zone, preventing the crack faces to open locally. In order to take that phenomenon into account, contact elements at crack faces should be used in numerical Fracture Mechanics analyses to avoid crack face interpenetration. However, usual Fracture Mechanics analyses do not consider such contact at crack faces as the non-linearity introduced in the system resolution leads to excessive computation time for industrial applications. Consequently, interpenetration of the crack faces occurs which is not realistic. This behavior is observed when the mode-I Stress Intensity Factor (SIF) has negative value along the crack front.
In the present work, Fracture Mechanics simulations are conducted to assess the impact of including contact conditions at crack faces on mode I SIF considering linear elastic material conditions. Then, the behavior of the crack faces with respect to increasing load is assessed through J-integral calculations considering elastic-plastic material conditions. Those results along the crack front in the tensile zone are assessed for different cracks and types of loads. All these analyses intend to draw up a statement about the necessity to model contact conditions at crack faces in flaw acceptability assessments.
Research on Determination of Obround Shell Thickness
Authors: Jin Yao 
Published: November 2024

Abstract
The analysis and design of obround components has been difficult and complex due to the lack of theoretical solutions. The existing design codes use empirical formulas to determine the wall thickness for obround components. To make the wall thickness acceptable, trial and error is inevitable. Since the results are not precise, the thickness determined is not the minimum required thickness, MRT. The closed-form solution proposed recently makes it possible to directly determine the wall thickness for obround components. In this paper, a new method for determining the MRT of obround shells is proposed. In the method, an obround shell is imagined as being stretched laterally from a cylindrical shell or parent cylinder. As the parent cylinder continues to be stretched, the wall thickness of the obround shell should continue to increase to remain the maximum hoop stress constant. The MRT of the obround shell should be related to the MRT of the parent cylinder and the straight shell length of the obround shell. Parametric study is performed to investigate the relationship among them. Empirical expressions are used to describe those relationships. Using the proposed design method, the determination of the MRT of obround members becomes the determination of the MRT of the parent cylinders and additional parameters. The MRT of obround members is determined directly. The case study demonstrates that the proposed method is an efficient and accurate design process for obround members. The possibility of using this method in Fitness-for-service is explored. The new method is used to reassess operational safety in the event of vessel materials deterioration.
Derivation of Input Distributions for Probabilistic Evaluation of PT/CT Contact in CANDU Reactors
Authors: Nadeau Eric , Baniak Adrian 
Published: November 2024

Abstract
CANDU® nuclear reactors are comprised of 380 or 480 fuel channels, each having a pressure tube installed concentrically inside a calandria tube. Each PT contains 12 fuel bundles. Four helicoidal annular springs, also known as spacers, provide support to the PT and prevent contact between the two tubes.
In 1983, the PT in channel G16 at the Pickering A Unit 2 ruptured unexpectedly. It was found that, in the older CANDU design, the loose-fitting spacers might move large distances from their design locations resulting in long unsupported spans. This eventually leads to the PT contacting the CT, with the contact spreading axially over time. Because the moderator on the outside of the CT is much cooler (about 70 °C) than the PT (&gt; 260 °C), this results in a cold region in the PT at the location of contact. The dissolved hydrogen in the PT can precipitate in the form of hydrides at the cold spot to form zirconium hydride blisters, which may crack, initiate delayed hydride cracking (DHC), and eventually lead to PT rupture.
The industry has been relying mostly on the Spacer Location and Repositioning program to prevent PT/CT contact. The PT/CT gap profile is also measured on a subset of FCs in each reactor during regular fuel channel inspections and during SLAR campaigns. To assist the CANDU operators with a risk-informed FC management program, a probabilistic methodology was developed to assess the probability of PT rupture resulting from contact and blisters.
The most critical inputs are the PT creep distribution and the end-slope distributions at each end of the PT. The derivation of those distributions for the reactor core is performed using a benchmark methodology comparing the predicted and measured PT/CT gap profiles. A probabilistic reactor core assessment is then performed to rank individual FCs by risk and determine a SLAR scope.
Since PT/CT gap is also measured in many of the inspected channels, there is a need to integrate the additional information from the gap data into the assessment to avoid identifying at-risk channels unnecessarily for subsequent SLAR scopes. For this purpose, a channel specific benchmark methodology has been developed to refine the PT creep and end-slope distributions in FCs with measured gap.
Therefore, for channels with no PT-CT gap information, the assessment is performed with core distributions, while for channels with PT-CT gap information, the assessment is performed with channel specific distributions.
Research on Effects of Surface Finishing and Mean Stress on Fatigue Lives of Notched Specimens: Mean Stress Effect for Notched Specimens of Carbon Steel
Authors: Wang Yun , Nakane Motoki , Hirano Akihiko , Takanashi Masahiro , Kitamura Yoshihide 
Published: November 2024

Abstract
DFC3 and DFC4 subcommittees in the Japan Welding Engineering Society (JWES) have investigated the mean stress effect and its correction methods on fatigue analysis for carbon steel STPT370 (equivalent to SA-106 Gr.A) in consideration of stress concentration.
The Modified Goodman approach has been widely applied for mean stress correction. However, according to the investigation results from polished smooth specimens, the Smith-Watson-Topper (SWT) approach showed higher rationality for mean stress correction. In this work the applicability of SWT approach was discussed for notched specimens.
Polished smooth specimens and notched specimens with stress concentration factors of 1.5 and 1.8 were prepared for fatigue tests. Firstly, the regression curves of both smooth and notched specimens were obtained from fully reversed fatigue tests. Secondly, mean stress fatigue tests for notched specimens were conducted at several loading levels. For both stress concentration factors, the data of mean stress fatigue tests dispersed below the regression curves of fully reversed fatigue tests, indicating that the fatigue strength of notched specimen could be reduced by the mean stress effect for this material. The elastoplastic analysis of Finite Element Method was conducted for estimating Mises equivalent stress and Mises equivalent strain at the bottom of notch. With these parameters, the equivalent stress amplitude Seq of SWT approach was calculated. For comparison purpose, Seq was also calculated by correcting the nominal stress amplitude and mean stress directly with the stress concentration factor Kt. Finally, the applicability of SWT approach for notched specimens was discussed by comparing the equivalent stress amplitude Seq to the fictitious elastic stress amplitude Sa of the regression curve of smooth specimens.
According to the results of this work, it was concluded that the equivalent stress amplitude Seq of SWT approach was available to mean stress correction for the notched specimens of STPT370.
Evaluation of Single Stud Replacement in Standard Piping Flanges
Authors: Brown Warren , Godfrey Darryl , van Zyl Gys 
Published: November 2024

Abstract
Single Stud Replacement (SSR, also known as hot-bolting) on the flanges of in-service piping is required on occasion to replace excessively corroded bolting, environmentally cracked bolting or to reduce the scope of work during turnarounds. Removal of a stud from a pressurized bolted joint is associated with an increased risk of leakage and a method to evaluate risk associated with SSR is currently under consideration for inclusion as an appendix in ASME PCC 1. In this paper, the authors explore the suitability of different methods of analysis for SSR, including the calculation of the reduction in gasket stress due to load loss associated with removal of a stud and using this result to assess the potential for leakage of the joint.
An advanced SSR calculation method was developed and applied to standard ASME B16.5 flanges of all sizes and classes. The results were then verified against finite element analyses performed on a sample of standard flanged joint configurations. Current ASME PCC-2 guidance regarding pressure limitations for safe SSR are also examined, in order to establish whether or not they are effective or appropriate. The results and conclusions of this study are presented, along with a discussion on how the evaluation method can be used to assess risk in combination with other factors that have an influence on the probability and consequence of leakage during SSR.
Study on the Discharge Characteristics of Multi-Hole Nozzles and Feasibility Verification for Built-In Nozzle Flapper in Air Spindle
Authors: Xu Peimin , Inaba Kazuaki , Takeishi Hisami , Kagawa Toshiharu 
Published: November 2024

Abstract
To improve the production efficiency of semiconductors, in the past we proposed a compensation system that uses a nozzle flapper as a distance sensor to adjust the air bearing to improve processing accuracy. Although the feasibility of the single-hole nozzle flapper system has been verified in past research, its static characteristics and structure cannot meet the requirements of the air shaft in actual engineering applications.
In this paper, we propose the design of the multi-hole nozzle flapper from the perspective of static characteristics. On the other hand, to ensure the compactness of the air spindle, a built-in nozzle flapper was designed. The static properties of the two types of nozzle flappers and the structural parameters that influence them were experimentally explored.
Using Zero Added Corrosion Allowance for API 650 Tank Components For Various Refining Services
Authors: Ardaniel Zesan , Shargay Cathleen , Basic Michael , Soltaninia Shahab 
Published: November 2024

Abstract
Storage tanks are commonly used equipment in many industries and for refining, they are typically designed in accordance with API 650 [1]. API 653 [2] is used once the tank enters service for setting the minimum inspection and repair requirements for maintaining the tank integrity. Many designers add corrosion allowances to carbon steel storage tank shell, bottom, and roof plates. However, doing this can lead to redundant or excessive corrosion allowances as some “extra thicknesses” are already obtained using API 650 designs. These “extra thicknesses” are shown by comparing the initial required thicknesses in API 650 (without added corrosion allowance) to the corroded thicknesses which require repair in API Standard 653. The differences are, by definition, corrosion allowances. This paper shows the thickness calculations for each major tank components, including the shells and bottoms, per both the API 650 and API 653 standards. In addition, this paper provides recommendations for adding additional corrosion allowances in a few highly corrosive tank services in refining and other similar industries. However, this analysis shows that using zero added corrosion allowance is appropriate for many services as the built-in corrosion allowance is already sufficient.
The Impact of Tube Array Compactness on the Generation of Acoustic Resonance
Authors: Noufal Rasha , Kishawy Hossam , Mohany Atef 
Published: November 2024

Abstract
This study presents an experimental investigation into the effects of tube array compactness on self-excited acoustic resonance. The primary focus is on varying the number of rows and columns in the tube array, with rows ranging from 1 to 9 and columns from 2 to 3. The experimental results demonstrate a clear correlation between the compactness of the tube array and the occurrence and strength of self-excited acoustic resonance. Specifically, an increase in the number of columns was found to significantly enhance both the occurrence of excitation and the amplitude of the generated acoustic pressure. Additionally, increasing the number of rows led to the excitation of higher acoustic modes. These modes were observed to synchronize with the wake of the tube array, as evidenced by phase-locked particle image velocimetry (PIV) measurements. This synchronization indicates a complex interaction between the acoustic field and the fluid flow, wherein the phase of the excited acoustic mode’s particle velocity plays a critical role.
Study on Industrial Computed Tomography Detection and Identification of Inclusion Defects in Thick-Wall Polyethylene Pipe Butt Fusion Joint Within Nuclear Power Plant
Authors: Shi Yan , Tao Yangji , Shen Zitao , Shi Jianfeng , Miao Cunjian , Tang Ping , Guo Weican 
Published: November 2024

Abstract
High-density polyethylene pipe exhibits notable corrosion resistance and mechanical properties, and has been applied in nuclear power plants. Due to operational efficiency and safety considerations, polyethylene pipe used in nuclear power plant generally features considerable wall thickness, which poses a huge challenge for radiographic non-destructive testing of the embedded defects. In this study, the effects of X-ray source tube voltage, the number of digital radiography image merging, and the number of scanning frames utilized for three-dimensional computed tomography image reconstruction on the quality of industrial computed tomography images of polyethylene pipe butt fusion joint with a wall thickness of 80 mm were systematically researched. A method for detecting and identifying inclusion defects in thick-wall polyethylene pipe based on industrial computed tomography technology and image morphological method was proposed. It was found that the critical parameter impacting defect recognition was contrast to noise ratio rather than signal to noise ratio. For inclusion defects that were easily missed, the Top-Hat algorithm was used to automatically identify inclusion defects in thick-wall polyethylene pipe butt fusion joint. Additionally, these computed tomography results were validated by phased array ultrasonic testing results, indicating its potential for quality surveillance and failure analysis of polyethylene pipe within nuclear power plants.
Stress and Strain Analysis of Sealing Cup With Internal Groove of Pipeline Inner Inspection Tool in Dented Oil and Gas Pipeline
Authors: Wang LuMing , Dong ShaoHua , Li Yong , Liu GuanYi , Zhang Hang , Tian Cheng 
Published: November 2024

Abstract
As an important mode of oil and gas transportation, pipelines will produce different forms of defects with the increase of service life and the change of external environment. Regular inspection in pipeline is an important way to ensure the safe operation of pipeline. As an important driving component of the pipeline inner inspection tool, the reducing ability of the sealing cup determines whether it can have stable passability when the inner diameter of the pipeline changes or when defects such as dents occur in the pipeline. This article designed a conical sealing cup with an internal groove structure, and the kinematic simulation model of the pipeline inner inspection tool in the non-destructive straight pipe was established based on the finite element method. A push experimental platform was established for the study, and strain data of the sealing cup before and after entering the pipeline were collected. The trend of change was in good agreement with the simulation curve. In order to avoid the stuck of pipeline inner inspection tool in the pipeline dents, the simulation study was conducted on a 6%OD dent defect pipeline using a 19mm thick sealing cup as an example. The study showed that the groove morphology of the cup in contact with the defect pipeline stretched towards both sides, and the surrounding area of internal groove contracted inward to promote the overall diameter change of the cup. Compared to the cup without groove, the maximum contact stress was significantly reduced, which proves that it has better diameter reducing ability and higher passability. According to the model introduced in this article, it can provide guidance for the application of sealing cup with internal groove.
Non-Destructive Testing Study of Hydrogen Storage COPVs Based on Digital Shearography Technique
Authors: Wen Ange , Ma Li , Li Yifan , Wang Shoulong , Liu Changchen , Ying Kaidi 
Published: November 2024

Abstract
Composite overwrapped pressure vessel (COPV) is a vital component of the high-pressure hydrogen storage system used in hydrogen fuel cell electric vehicles (FCEV). However, the heterogeneity of fiber reinforced polymer (FRP) and the influence of the manufacturing process often result in manufacturing defects such as delaminations and cracks. These defects exhibit random variations in size and location, which not only leads to complex local mechanical behavior but also poses challenges in their detection. This study presents the utilization of digital shearography techniques for non-destructive defect detection in COPVs subjected to internal pressure. A Type III COPV of product model CHG3-383-55-35S/A (according to Chinese standard GB/T 35544) was subjected to various loading states and shear conditions in the experimental investigation. During the test, the characteristic shear fringe patterns caused by the local displacement gradient distortion was recorded in shearograms. The shearography technique leverages the understanding that defect-induced distortion in the displacement gradient is translated into anomalies in the fringe pattern. By analyzing the characteristic fringe patterns obtained in different loading state, the use of shearography approach effectively identified and revealed the size and location of embedded delaminations and surface micro-cracks. In the end, the study also explored the influence of the measurement parameters, such as inspection field of view (FOV) and shear direction, on the detection sensitivity of shearography results. The work aims to provide a reliable and efficient testing scheme for defect detection in COPVs.
GDDM: A Solution for Cross-Domain Class Imbalance and its Application in Fault Diagnosis
Authors: Fan Xiaoxuan , Duan Lixiang , Jiang Lumeng , Yu Shengyang 
Published: November 2024

Abstract
Timely and accurate fault diagnosis of mechanical equipment helps improve the safety of pipeline system. In practical cross-domain diagnostic tasks of mechanical equipment, there exists a problem of cross-domain class imbalance, which makes it difficult to effectively transfer knowledge from the source domain to the target domain. To address this issue, this paper proposes a Graph Data-Driven Method (GDDM) for cross-domain discriminative feature extraction. The key of this method lies in using a designed Graph Construction Model (GCM) to extract discriminative features across domains. Specifically, the GCM uses pearson similarity to measure the inter-class differences between samples and uses them as the weights for connections between graph nodes. Based on this, it constructs graph data that integrates sample features and their relationships, effectively modeling inter-class differences among samples. Furthermore, by inputting the graph data into a spectral graph convolutional network, it extracts discriminative features, overcoming class bias and achieving effective cross-domain knowledge transfer under the condition of cross-domain class imbalance. The proposed method is applied to the publicly available bearing dataset from the Case Western Reserve University, and experimental results demonstrate its effectiveness and stability in handling cross-domain class imbalance data, achieving effective cross-domain knowledge transfer and fault diagnosis.