bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of Depth Defects During Pipeline Magnetic Flux Leakage Detection Based on the AVOA-BPNN
Authors: Xu Lushuai , Dong Shaohua , Peng Donghua , Wei Haotian , Ma Yundong 
Published: November 2023

Abstract
The complex operational conditions of in-service pipelines and the extended service time make them susceptible to metal loss, which can lead to pipeline failure. However, quantifying the defect depth presents a challenge to current research. The depth quantification accuracy of pipeline defects can be improved, and the defect state of long-distance pipelines can be accurately controlled by building a model based on the internal magnetic flux signal. This study performed a pulling experiment for internal magnetic flux leakage detection in pipelines and extracted the triaxial leakage signals of 60 internal and external pipeline defects. Firstly, Pearson correlation coefficient is used to extract the seven main influencing factors affecting the depth of pipeline leakage defects, namely axial signal peak-valley value, axial signal waveform area, axial signal waveform energy, circumferential signal peak-valley value, radial signal peak-valley value, axial integral signal peak-valley value, and radial integral signal peak-valley value. Secondly, the initial weights and thresholds of the backpropagation neural network (BPNN) were optimized using the African Vulture Optimization Algorithm (AVOA). Furthermore, an AVOA-BPNN-based defect depth prediction model for pipe leakage detection was established to address the problem challenge of the BPNN algorithm easily falling into the local optimum. The magnetic triaxial leakage signals of the internal and external pipeline defects collected via 60 sets of drafting experiments were used as examples, while a particle swarm optimized BPNN (PSO-BPNN), genetic algorithm optimized BPNN (GA-BPNN), and an unoptimized BPNN were used as models for comparative analysis. The results showed that optimizing the BPNN using AVOA substantially improved the prediction accuracy of the BPNN model. The AVOA-BPNN model predicted 12 sets of pipe defect depths with an average relative error (MRE) of only 2.67% and a determination coefficient (R2) of 0.99800, which exceeded the values of the BPNN, PSO-BPNN, and GA-BPNN models. The AVOA-BPNN uses the internal leakage detection signal to predict the depth of pipe defects, supporting effective decision-making regarding pipe inspection and maintenance.
Development of a New EPRI Elastic-Plastic Fracture Mechanics Handbook
Authors: Anderson Ted L. , Dodds Robert H. , Thorwald Greg V. , Dessein Thomas , Shim Do Jun 
Published: November 2023

Abstract
Research funded by the Electric Power Research Institute (EPRI) in the 1980s produced a series of Ductile Fracture Handbooks including J-integral solutions for structural components with cracks. The EPRI Handbook series was to serve as an elastic-plastic equivalent to stress-intensity factor handbooks that various authors published in the 1970s. The original EPRI research in this area significantly advanced the field of elastic-plastic fracture mechanics (EPFM), particularly for ductile instability analysis of structures. However, the initial EPRI Handbooks were restricted to simple two-dimensional configurations, so were of limited practical value. Subsequent EPRI Handbooks published in the late 1980s contained numerous errors, and the technical basis of some solutions was not documented.
Advances in computing technology in the past four decades have now made EPRI’s original vision practical. A project is currently underway to produce a new EPRI EPFM Handbook. This project entails over 23,500 3D elastic-plastic finite element analyses of cracked configurations. The process of generating the meshes, editing the input files, running the FEA solver, postprocessing the results files, and fitting results to parametric equations is highly automated. Most computations are performed on an EPRI (Linux) cluster with 36, high-end nodes. New parametric equations for the J-integral, crack opening area (through-wall cracks), crack mouth opening displacement, and load-line displacement (laboratory specimen configurations) are developed in this study.
Damage Modeling in Metal Additive Manufacturing Process Simulations
Authors: Fietek C. , Sakai J. , Love A. , Park Y. H. 
Published: November 2023

Abstract
Additive manufacturing (AM) is a process of making three-dimensional parts from a digital file layer by layer. One of the most popular methods of additive manufacturing is selective laser melting (SLM), which uses a high-power laser to melt and fuse metallic powder particles together. Thermo-mechanical simulations are important for the successful design and implementation of AM processes, as they can predict potential process-induced distortions and residual stresses to the final parts. We find that SLM can lead to the formation of voids, porosity, and other defects in the final part, which can degrade the mechanical properties. One macro-scale approach to modeling these defects is by using a ductile damage criterion like that developed by Johnson and Cook. To predict this damage in Abaqus Standard, a UMAT subroutine was developed implementing the Johnson-Cook plasticity and damage models. To validate this user-subroutine, mechanical examples of increasing complexity were used. In this work, we couple thermo-mechanical finite element simulations with the Johnson-Cook damage model to study the effects of SLM on the propagation of process-induced damage within a part made of Inconel 718. Overall, the process-induced damage could be significant to failure predictions of a deployed part and is an efficient way of predicting material degradation from manufacture.
Flow-Visualization of a Prototypical Helical Coil Test Bundle Undergoing Vibrations
Authors: Sutton Noah , Maher Blake , Vaghetto Rodolfo , Hassan Yassin 
Published: November 2023

Abstract
Flow-Induced Vibrations (FIVs) have been of the upmost interest in the engineering community due to their large role in safety and reliability design in heat exchangers. This has especially been true in the nuclear sector as focuses have shifted to Small Modular Reactors (SMRs). These reactors aim to decrease the volumetric footprint of reactors, while maintaining a reasonable power output. To achieve this more compact heat exchangers and faster flow rates are implemented. These changes lead to larger vibrational amplitudes in the system and must be accounted for. This study utilizes Particle Image Velocimetry (PIV) to provide flow visualization of a prototypical section of a Helical Coil Steam Generator (HCSG) with a clockwise, counterclockwise tube rotation undergoing vibrations. The bundle of interest utilizes a canti-levered attachment approach in order to lower the natural frequency of the system. The flow field statistics are studied intensively in order to gain greater understanding of the FIV phenomenon. Several advanced analysis techniques are utilized in this pursuit such as: Proper Orthogonal Decomposition (POD), Wavelet, and spectral analysis.
A Component-Based Hybrid Reduced Basis Method for Creep Analysis of Complex Structures According to the Omega Model (API 579-1/ASME FFS-1)
Authors: Nguyen Thanh Loi , Chau Nguyen Kha , Cao Nhan Tien , Huynh Di Bao Phuong , Knezevic David J. , Jung Gonghyun 
Published: November 2023

Abstract
Finite element analysis (FEA) for creep life assessment of large-scale structures is challenging due to the highly nonlinear (iterative) nature of creep analysis, the long timescales involved, and the substantial number of FEA degrees of freedom to consider strong interaction between components in full scale system. One of the methods explored to overcome the challenges was the linear-nonlinear hybrid formulation which significantly reduces analysis time with reasonably acceptable accuracy.
The approach used in the analysis takes advantage of the fact that, in practice, we are usually interested in a specific region of a system where creep develops faster than the other regions, and thus we can treat that local region as a locally nonlinear problem that will be analyzed using nonlinear finite element analysis (FEA) while the other regions will be analyzed using Reduced Basis Finite Element Analysis (RB-FEA). The FEA and RB-FEA regions are fully coupled via the Hybrid Solver approach, yielding an accurate solution for the overall nonlinear system. The accuracy of the solution over the entire model is maintained by employing appropriate component training processes to infer the behavior of the field over the entire model, including the linear-nonlinear interface.
The paper presents the creep analysis results for simple Tee joint, multiple Tee joints in a piping, and more complicated piping system consisting of main header, sub-header, and smallbore piping, and demonstrates validity and effectiveness of the proposed method by comparing stress relaxation, cumulative creep strain, solving time and memory consumption to standard FEA.
Generation of a Fatigue Design Curve Suitable for Use on Additive Manufacture Nuclear Plant Components Produced From 316LN Stainless Steel Using Laser Powder Bed Fusion
Authors: Press William , Ferriday Jay , Jones Thomas , Dear Matthew , Poole David 
Published: November 2023

Abstract
The Additive Manufacture (AM) of nuclear plant components using Laser Powder Bed Fusion (LPBF) technology, offers opportunities to reduce costs and improve production lead-times. Cost reductions can be achieved by reducing the amount of raw material required, reducing the amount of machining conducted, and eliminating the welding together of sub-assemblies.
However, AM is a relatively new manufacturing technology, and although now seeing greater usage in industry generally, there are still very few examples of where the technology has been applied to components used in safety critical applications. Furthermore, it is not currently covered by the American Society of Mechanical Engineers (ASME), Section III, nuclear design code. For nuclear plant applications, it is imperative that accurate and robust material property data is established to input into design assessment and analysis.
This paper presents Rolls-Royce’s approach to the derivation of a fatigue design curve specific to AM LPBF 316LN stainless steel with Hot Isostatic Press (HIP) process step, for use in ASME III, Subsection NB-3200 or NB-3600 fatigue crack initiation assessments on nuclear plant applications within its portfolio, including small bore globe valves and pipework tees and reducers.
As part of a safety justification strategy for the implementation of AM LPBF small bore globe valves for nuclear plant Rolls-Royce carried out an initial suite of materials testing, including in-air uni-axial fatigue endurance tests on AM LPBF 316LN stainless steel samples. The limited data generated was seen to fall within the expected scatter when compared to the data upon which the NUREG/CR-6909 air best-fit curve is based. However, on completion of further testing in various test orientations on multiple powder batches and builds a more complex fatigue behaviour was observed.
This paper provides an overview of the investigation into the orientation effects on the material fatigue behaviour, especially at high strain amplitudes, and how a combined best fit curve has been constructed for this material using either a fit to the limiting orientation data or the NUREG/CR-6909 mean curve at each point across the S-N curve, whichever is lower. A fatigue design curve is then produced from the best fit curve by first applying a mean stress correction and then applying transference factors on stress and on cycles to account for material variability, component size and surface finish, and load history.
The fatigue design curve generated specific to AM LPBF 316LN stainless steel is judged to be suitably conservative for the design assessment and analysis of the material on nuclear plant applications, including the AM small bore globe valves which have also undergone supporting ASME, Section III, Appendix II, thermal cyclic testing.
Low-Cycle Fatigue Evaluation of Coke Drum Base Materials and Welded Joints - A Summary of OSU Research Project and Future Work
Authors: Zhang Shutong , Romo Sebastian , Giorjao Rafael A. , Berkson Jacque , Penso Jorge , Guo Haixia , Ramirez Antonio J. 
Published: November 2023

Abstract
Coke drums are critical units in the delayed coking process to produce lightweight oil products from heavy residual oil. The fulfillment of the designed coke drum lifetime is often obstructed by low-cycle fatigue damage over cyclic thermal and mechanical loading. Considering the tremendous cost of drum replacement and production loss due to shutdown, the coke drum lifetime extension is of great economic significance in the oil and gas industry. A research project regarding coke drum fabrication and repair was initiated in the Manufacturing & Materials Joining Innovation Center (MA2JIC) at the Ohio State University in 2016. The project includes two phases of work. The first phase of the study (2016∼2019) focused on the external weld repair of coke drum materials, while the ongoing second phase of the study (2019∼2023) addressed coke drum fabrication and repair. A novel low-cycle fatigue testing approach was developed using Gleeble thermo-mechanical simulator and was applied to evaluating the performance of coke drum base materials and welded joints under cyclic deformation. The project goal is to improve the fundamental understanding of materials and joint performance that allows the optimization of coke drum design, fabrication, and repair. In this technical paper, the key methodologies and achievements of the project will be introduced, and some future work will be proposed for the next step.
High Temperature Hydrogen Attack – A Case History
Authors: Dalal Mitul , Penso Jorge , Hau Jorge 
Published: November 2023

Abstract
High Temperature Hydrogen Attack (HTHA) is defined as an irreversible degradation of the mechanical properties of steel. HTHA can detrimentally affect the service life of carbon steel and low chrome pressure equipment and piping components in the petroleum refining and related industries. HTHA involves high temperature reaction of absorbed hydrogen with carbon in the steel to produce methane. The hydrogen/carbon reaction can cause surface decarburization of the steel. Molecules of Methane are too large to diffuse through the steel and the reaction to methane occurs at grain boundaries and at inclusions or other microstructural imperfection in the steel. As a result, internal methane pressure builds up, initially forming bubbles or cavities, then micro-fissures, and finally fissures that may combine to form cracks. Long-term exposure to high temperature hydrogen environment can lead to volumetric damage which can deteriorate mechanical strength of pressure equipment and piping components and accelerate crack-like flaws. There have been multiple industry failures reported due to HTHA.
This paper summarizes a case history of a HTHA damage in a post weld heat treated (PWHT) carbon steel heat exchanger channel, a reactor effluent exchanger in hydrocracker unit. Summary includes detail data processing of the operating conditions, online monitoring experience and comparison to offline inspection. Thorough metallurgical analysis was performed, and operational data were utilized for predictive model comparison. Failure samples were utilized for an ongoing, multi-year Joint Industry Project (JIP) for fingerprinting.
On the Effect of Rising Liquid on Coke Drum Skirt Fatigue Life
Authors: Fernando John , Kwok Henry , Chan Luke , Iverson Millar , Ju Feng , Yuen Simon 
Published: November 2023

Abstract
Due to the severe thermal gradients that develop on coke drums as they are filled with hot oil during coking and water during quenching, accurate modeling of the heat transfer from the fluid to the vessel is critical in the analysis of coke drums. To this end, transient thermo-mechanical simulations typically utilize point measurements of thermal profiles extracted from coke drums in operation, but oftentimes use these point measurements as uniform thermal inputs across the entire inner surface of the drum. In reality, non-uniform thermal fields develop along the height of the vessel depending on the fluid fill rates, the effects of which have also been considered in a number of studies to date. The current study focuses on comparing these two temperature methodologies by estimating fatigue life at the skirt-to-vessel attachment weld (a prevalent location of fatigue damage) for two common skirt designs, to assess the feasibility of the former, simpler approach. Although the results indicate similarities in the overall trends, differences in fatigue-life estimates of up to 20% are calculated between the two approaches. Given these differences, the methodology presented in this study should be considered when a higher level of accuracy is required in estimating fatigue life. However, the alternative, simpler methodology provides conservative estimates of the fatigue life when directional insight or expediency is paramount.
Ethylene Oxide Reactor Engineered Weld Repair Case History
Authors: Dalal Mitul , Penso Jorge , Hau Jorge , O’Brien Steven , London Tyler , Seow Cui Er , Carollo Vallerio , Chukkan Jazeel , Janin Yin Jin , Rothwell John , Howse David , Consonni Marcello 
Published: November 2023

Abstract
A pair of ethylene oxide reactors have been in service for approximately twenty years. The shell material of construction is SA-543, Grade B, CL.1 They were designed according to ASME Section VIII Div.2. A temporal repair work was engineered to remove cracks and reweld. One-side welding approach was qualified per ASME Section IX. It is widely accepted that tensile residual stresses can be detrimental to the integrity of welded components. A combination of weld residual stress simulation and measurement was performed to predict and characterize the weld residual stresses. Generation and analysis of the models followed established best practice for computational welding mechanics. The weld residual stress profiles were optimized after several interactions and mockup coupons were prepared. The approach included the generation a representative computational welding mechanics model; calibration the free parameters in the model against test data; and then validation of the predictions of residual stresses against various experimental residual stress measurements. The residual stress states in both the original weld mock-up and the as-repaired weld were determined using two different experimental techniques: Air-abrasive Centre Hole Drilling (ACHD) for surface residual stresses and incremental Deep Hole Drilling (iDHD) for through-thickness residual stresses. Mechanical testing included tensile and impact testing along with hardness profiles. Controlled deposition approach was implemented to lower hardness. Extensive temporary repairs were successfully executed. New reactors with lower strength steel and post weld heat treatment are being fabricated for permanent replacement.
Relationship Between Natural Period and Strength of Actual Piping Systems Subjected to Seismic Motion
Authors: Tamura Ichiro , Ishii Yuya , Kamatani Keita , Tamura Shinji 
Published: November 2023

Abstract
The responses of single-degree-of-freedom systems subjected to seismic motion are obtained through the well-known inelastic response spectra or constant-ductility response spectra using the natural periods and yield accelerations. Similarly, the modal responses of multi-degree-of-freedom systems subjected to seismic motion are obtained through the spectra using the natural periods and modal yield accelerations, i.e., the modal yield strengths normalized by the modal masses. The relationship between the natural period and modal yield acceleration of each mode of piping systems was investigated for straight and Z-piping systems in a previous study, and was represented by the proposed piping yield diagrams. In this study, their relationship was investigated for actual piping systems in a nuclear power plant, and was represented by the diagrams. Based on these diagrams, the lower limit line of piping yield diagrams was proposed. Using the lower limit line and inelastic response spectra, the maximum responses of piping systems to various seismic motions can be estimated without performing individual dynamic analyses.
Study on Sealing Reliability of High-Pressure Flange for Bolt Axial Stress Measurement Based on Magnetic Memory Testing
Authors: Wang Yanran , Fan Jianchun 
Published: November 2023

Abstract
The high-pressure flange in the wellhead device frequently uses the octagonal gasket sealing method, which provides the optimal sealing effect by ensuring adequate bolt preload. Thus, the change in bolt preload is the primary factor affecting sealing performance. In order to quantitatively evaluate the reliability of high-pressure flange sealing, the bolt preload measuring experiment based on the metal magnetic memory effect was carried out in this research. The experimental findings demonstrate a linear link between the characteristic parameters of the magnetic signal and the bolt preload. The 6BX-type high-pressure flange model for a wellhead device was employed in order to study the effect of varied bolt loosening and load fluctuation circumstances on sealing performance. In addition, the simulation results demonstrate that the bolt pre-tightening force of the flange and the contact stress on the gasket sealing surface increase logarithmically under internal pressure. Lastly, the leakage rate model for the sealing surface is presented based on the simulation results of the seal clearance height of the rough surface. This research provides a new method for assessing the sealing reliability of high-pressure flanges of type 6BX used in wellhead equipment.
Research on China’s LNG Terminal Standard System and Intelligent Management Mode
Authors: Hu Hangjian , He Yongli , Liu Xin , Duan Zhixiang 
Published: November 2023

Abstract
China’s LNG industry started late, and there are insufficient experience and imperfect systems in the construction, operation, production, and management of LNG receiving stations. Moreover, the construction and application of LNG receiving station standard system lags, and it cannot be effectively improved in view of the changes in China’s national conditions and international energy situation. It is difficult to form an efficient standard system and management system unique to LNG receiving stations; The entire LNG terminal cannot effectively form an effective, scientific, and organic unity.
In view of the above problems, this paper puts forward the requirements for intelligent management of the standard system of LNG receiving stations and the relevant measures and suggestions for intelligent management. Based on many research and collection of relevant industrial standards of LNG receiving stations, combined with the relevant requirements of China’s enterprise standard system construction, the corresponding standard system tables for the design, construction, operation, management, maintenance, and safety of LNG receiving stations are established. Relying on computer and big data technology, combined with intelligent management and other functional requirements, relevant standard system management software and database have been established. The system well realizes the management, update, and review of the standard system, and establishes the PDCA cycle with the quality management system and environmental management system, takes the standardized related activities and resources as a process, manages the whole process of LNG receiving station operation and production, and complements and supports different systems, providing important technical support for the sustainable development of LNG receiving station.