bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Ultrasonic Phased Array Imaging Technique for Direct Contact Inspection on Double Curved Surface
Authors: Cheng Jingwei , Fan Zhichao , Chen Xuedong , Bu Yangguang , Wang Haibin , Wang Zhe 
Published: November 2022

Abstract
Ultrasonic testing technique is commonly used for nondestructive inspection of pressure vessels and pipelines. Normally, ultrasonic phased array system can effectively and efficiently image different types of defects within the structures through direct contact method. However, the double curved geometries of inspection targets (e.g. pipe elbows, pipe weld joints and turbine blades) give rise to challenges in direct contact between probe and surface. Therefore, based on the full matrix capture and total focusing method (TFM), this paper uses a conventional phased array transducer with flexible wedge to detect and image a double curved sample with different depths of side drilled holes. The test specimen is fabricated in a ring shape with an outer diameter of 150 mm, an inner diameter of 100 mm and a 2 mm high weld reinforcement. It is found that the full matrix data can be captured to image the structure interior by either extracting the surface profile or directly imaging with preset surface dimensions. The proposed technique has also demonstrated its capability on realizing high-resolution imaging of 1 mm side drilled holes at different depths. Our promising results show that the method has the ability to reliably locate and quantitatively evaluate the defects with complexly shaped structure.
Filament Wound Composite Pipes Subject to Torsion and Bending Loads
Authors: Farrugia Nicole , Camilleri Duncan , Ellul Brian , Muscat Martin 
Published: November 2022

Abstract
Filament winding has been extensively used to fabricate fibre reinforced composite pipes. The fibres are primarily oriented in such a way to increase the structural efficiency of the pipes to withstand internal pressure, that namely load the pipes in the hoop direction. However, the various intricate pipe systems and connections will also subject these pipes to torsional and bending loads. In this study different fibre orientation lay-up sequences consisting of four E-Glass /polyester resin layers were fabricated using a standard four-axis filament winding machine and experimentally subjected to torsion and bending load tests. During the curing process the samples were also vacuum bagged to minimise the void content. The respective volume fractions are also identified through ignition loss tests. The load versus deformation and ultimate failure load were recorded. The onset of first ply failure was also identified through acoustic/vibration measurements and observable differences in load/deformation plots. Different failure modes were observed ranging from buckling failure to matrix failure. The primary failure mode for pipes subject to bending was either compressive or tensile failure at the upper or lower strands of the pipe as a result of the imposed bending stresses. On the other hand, buckling or shear failure was observed in the pipes subject to torsional loading. The best fibre orientation based on loading conditions was identified. In the case of bending, the load carrying capacity increased when fibres are oriented closer to the axial direction, however care is to be taken to ensure that the pipes do not buckle. In the case of torsional loading, pipes with fibres oriented at 45° were able to sustain the highest load.
Energy-Based Very Low Cycle Fatigue Crack Growth Simulation for Seismic Application
Authors: Hwang Jin-Ha , Kim Yun-Jae , Kim Jin-Weon 
Published: November 2022

Abstract
In the previous studies, the energy-based damage model was developed by simulating cracked pipe fracture behaviour under seismic loading. The multi-axial fracture strain energy density, the parameter of energy-based damage model, was determined by standard tensile test data and monotonic cracked pipe test data. Very low cycle fatigue crack growth was simulated by applying the multi-axial fracture strain energy density under monotonic loading. When the previous energy-based damage model was applied to simulate cracked pipe fracture test under seismic loading, the simulated results were good agreement with experimental data under high load amplitude reverse cyclic loading and displacement controlled large scale cyclic loading. However, the conservative predicted results are shown in pipe test with low load amplitude and different load ratio.
In this paper, the energy-based damage model was improved by incorporating the effect of load amplitude and load ratio on multi-axial fracture strain energy density. The cyclic multi-axial fracture strain energy density increased by depending on the load amplitude and load ratios. The improved damage model was applied by pipe fracture test under seismic loading with various load amplitudes and load ratios. The pipe tests were subjected by using circumferential through-wall crack (TWC) and surface crack (SC) pipe specimen. The seismic loading consisted of two load amplitudes and two load ratios. The simulated results were compared with experimental data and validated.
A Recurrent Neural Network Method for Condition Monitoring and Predictive Maintenance of Pressure Vessel Components
Authors: Halliday Chris , Palmer Iain , Pready Nigel , Joyce Mark 
Published: November 2022

Abstract
High-fidelity physics simulations such as finite element analyses (FEA) provide accurate solutions to complex physical problems that are encountered in equipment subjected to transient conditions. However, such simulations come with significant computational expense, which often prevents them from being used for condition monitoring as a ‘digital twin’. Physics-based reduced order models (ROMs) seek to reduce this computational cost by using classical equations, augmented with empirical factors, to predict some unknown physical quantity of interest over time. Such ROMs are fast to run and simple to tailor for different load cases, but often require significant bespoke development effort. Additionally, developing the formulation of such ROMs becomes increasingly difficult as the complexity of the modelled physical phenomena increases.
Advances in Artificial Intelligence and Machine Learning have resulted in techniques that are ideally placed to address the shortfalls of ROMs and maintain their benefits. A common problem that a physics-based ROM attempts to solve is predicting an unknown time-varying parameter (such as stress) based on a set of known time-varying parameters. Recurrent Neural Networks (RNNs) are well suited to tackle exactly this problem as an RNN-ROM.
An RNN-ROM has been developed and validated against finite element analyses for a piece of rotating machinery subjected to complex thermal transients. Transient thermal datasets were extracted from locations of interest in an FEA representation of a rotating component and used as inputs to the RNN-ROM to predict time-dependent transient thermal behavior. The results were compared to the high-fidelity finite element model from which the input data was extracted; these results showed significantly improved accuracy compared to physics-based ROMs.
Case Study of Probability of Loss of Containment Due to Overpressure
Authors: Nunez Joseph , Hay Clifford 
Published: November 2022

Abstract
This research explores the equation in API 581 for determining the probability of loss of containment due to overpressure from a failure of a pressure relief device to open on demand. This paper explores the basis for the equation as presently written in API 581 and how that relates to the ASME Code for pressure vessels; specifically ASME Section VIII Division 1. A generic form of the equation is derived which can be broadly applied to equipment designed to any code of construction that provides a design margin on plastic collapse. This paper then provides several case study comparisons of the generic equation applied to various codes of construction; ASME VIII Division 1 (current edition), ASME VIII Division 2 (Class 1 and Class 2), and ASME B31.3. Results using a burst pressure design margin and isochronous creep rupture design margins are explored. Finally, a comparison with the nuclear service level elastic limits is provided for qualitative benchmarking.
This research provides end users engaged in risk based inspection activities for PRDs with information that can more accurately define the risk of loss of containment for equipment other than pressure vessels constructed to ASME VIII Division 1. This will allow more accurate results when determining inspection intervals for PRDs in accordance with the procedures in API 581.
Probabilistic Fracture Mechanics Codes for Piping International Benchmark – Part 1: Deterministic Comparisons
Authors: Homiack Matthew 
Published: November 2022

Abstract
This paper describes deterministic benchmark comparisons of 14 probabilistic fracture mechanics (PFM) codes. The benchmark problem focused on determining the leak-before-break behavior of a nickel-based alloy weld in a large-bore piping system of a pressurized-water reactor. The modeled degradation mechanism was primary water stress-corrosion cracking (PWSCC). The benchmark problem was deterministically analyzed with the PFM codes using their models for crack growth rates, stress-intensity factors, crack-opening displacements (CODs), crack transition from inside surface-breaking cracks to through-wall cracks, leak rates, and crack stability. Several output quantities of interest relevant to leak-before-break behavior were then compared. Other outputs as a function of the simulated component operating time were also compared, including the crack lengths and depths, stress-intensity factors, inside and outside surface CODs, and leak rates. An interpretation of these comparisons is provided in relation to the underlying models to better understand the effects of the different modeling approaches. Insights from this study will be used to inform probabilistic comparisons of the PFM codes, which will be presented in a subsequent paper.
Earthquake NaTech Risk Assessment, Monitoring and Management of Cylindrical Liquid Storage Tanks With Floating Roof in Major-Hazard Industrial Plants
Authors: Salimbeni Michela , De Angelis Maurizio , Vezzari Valerio , Ciucci Mariano 
Published: November 2022

Abstract
Earthquake is one of the natural events which is part of NaTech events (Natural Hazard Triggering Technological Disasters), due to interaction between natural and industrial risks. Industrial plants employ cylindrical liquid tanks with floating roof for storage of volatile and flammable products. Damages due to earthquakes affecting tanks with floating roof can cause major accidents involving dangerous substances, like hazardous releases, fires and explosions, especially due to the convective motion of the fluid caused by seismic excitation. The aim of this work is to inform about the most common damages in case of seismic event and to give some advice to seismic risk management through monitoring of critical elements of liquid storage tanks with floating roof. During an earthquake, damages to structural and non-structural elements can occur, and the non-structural elements are often the most involved in major accidents. In order to mitigate the consequences of a major accident, a monitoring system of the tank for management of the seismic risk can be installed, integrating new dedicated sensors into the existing monitoring network. The fiber optic sensors FBG (Fiber Bragg Grating) and FSI (Fiber Segment Interferometry) are a robust, multifunctional and removable alternative to the sensors already in use in the industrial field.
Accurately Predicting Transient Fluid Forces in Piping Systems Part 1: Fundamentals
Authors: Lang Scott A. , Walters Trey W. 
Published: November 2022

Abstract
Changes in the operation of piping systems — like valve closures or pump starts — propagate pressure waves that travel at acoustic velocity throughout the fluid. These pressure waves have considerable effect on forces, potentially generating dynamic loads upwards of 10,000 lbf (50 kN) in common configurations.
Some estimation methods used in industry for estimating transient forces neglect terms that may be important in some cases. Calculating forces due to these transients without simplification for transient liquid or gas flow is presented here in detail.
Combining Weld Residual Stress Predictions and Measurement for Use in Probabilistic Structural Integrity Assessments
Authors: Coules Harry , Simpson Christopher , Mostafavi Mahmoud 
Published: November 2022

Abstract
The use of residual stress information in probabilistic fracture assessments is hindered by difficulties in the quantification of uncertainty. At the same time, it is often necessary to consider residual stress data derived via two or more independent methods in an assessment: typically from a model of the process which introduced the stress, and from a direct physical measurement. The uncertainty in single weld process models is difficult to quantify and is strongly dependent on the process being modelled, the material constitutive behaviour assumed, and so on. Likewise, most experimental techniques for measuring deep residual stresses on welded metallic components, including relaxation methods such as Deep Hole Drilling and diffraction-based methods, also have multiple physical sources of uncertainty associated with them. This makes the uncertainty associated with single measurements difficult to estimate reliably.
We explore the use of inverse-variance weighting to combine such datasets through “characteristic” uncertainties derived from prior round robin studies, and we use data from the NeT TG4 residual stress measurement and modelling round robin to illustrate this approach. Although it requires some significant simplifications, it allows convenient synthesis of residual stress data while gaining more realistic uncertainty estimates than are typically available from single measurements. This is significant because straightforward yet robust uncertainty estimates will be key for enabling future structural integrity assessment methodologies.
Evaluation of Hydrogen Embrittlement Sensitivity of 4130X Material Based on the Disc Method
Authors: Zhai Jian-Ming 
Published: November 2022

Abstract
In order to evaluate the hydrogen embrittlement sensitivity of 4130X material, the effect of curvature radius of the high-steel ring on material failure mode and blasting pressure was firstly carried out, and then the hydrogen embrittlement sensitivity index was evaluated for disc samples with different surface roughness. The test results show that when the curvature radius of the high-steel ring is 0.5 mm, 1.5 mm, 2.0 mm, the material is mostly destroyed by shear. When the curvature radius is greater or equal to 4.0 mm, the material will be destroyed in the form of blasting. The blasting strength tested in hydrogen environment of 4130X materials decreases when the surface roughness increase from 0.1 to 4.1 μm.
For the HE sensitivity evaluation of 4130X by DPT method, it is recommended that the curvature radius should be greater or equal to 4.0 mm, and the surface roughness between 0.1 and 1.5 μm can meet the DPT requirements.
Accurately Predicting Transient Fluid Forces in Piping Systems Part 2: Applications
Authors: Lang Scott A. , Walters Trey W. 
Published: November 2022

Abstract
Part 1 of this series discussed in detail how to accurately calculate the reactions induced by pressure transients that travel at acoustic velocity in either liquid or gas piping systems. Part 2 applies these methods to a variety of realistic examples to further illustrate their use and to demonstrate areas in which traditional or simplified methods may impart significant error.
Investigating Weld Interface Cracking of 1.25Cr-0.5Mo Steel External Weld Repair with Alloy 625 Filler Metal due to Low-cycle Fatigue Failure
Authors: Zhang Shutong , Giorjao Rafael A. , Berkson Jacque W. , Penso Jorge A. , Guo Haixia , Yuen Simon , Ely Lisa , Ramirez Antonio J. 
Published: November 2022

Abstract
Welding repair has been widely used to restore the structural integrity of coke drums compromised by cracks due to low-cycle fatigue failure among other damaging mechanisms. Nevertheless, due to the heterogeneous mechanical and metallurgical properties, repair welds are susceptible to re-cracking during subsequent operations. The API 1996 report has shown that 88% of outer-diameter (OD) repair welds have experienced re-cracking in coke drums. The re-cracking susceptibility downgrades the efficiency of welding repair to extend coke drum operation life and may increase the complexity of coke drum maintenance. Hence, addressing the low-cycle fatigue failure of weld becomes a critical issue to optimize welding repair for coke drum maintenance. Alloy 625 is a commonly used Ni-based filler metal to perform coke drum repairs due to its good thermal and metallurgical compatibility with the base metal. However, weld metal dilution close to the weld interface changes local microstructure and mechanical properties from the rest part of the weld. In this study, an external repair welds of 1.25Cr-0.5Mo steel under as-received (Normalized and Tempered) and service-aged conditions with Alloy 625 using HP-GTAW process are evaluated based on low-cycle fatigue tests and failure analysis. Weld transition samples are extracted to encompass the transition from weld metal to base metal at the gage section. Low-cycle fatigue tests are performed at 0.7%, 1.0%, 1.5% and 2.0% strain amplitudes. Interfacial cracks are observed at lower strain amplitudes (0.7% and 1.0%) and failures at higher strain amplitudes tend to occur at the base metal region. Metallurgical characterizations are performed to characterize the microstructure at weld interface and measure the mechanical properties through micro hardness. Interfacial cracks are examined using Scanning Electron Microscopy. This study helps clarify how microstructure and mechanical properties contribute to the interfacial cracking of the Ni-base alloy and steel dissimilar joint.
PTFE Gasket Material Performance Variation With Thickness
Authors: Bausman Anita , Wilson Jeffery 
Published: November 2022

Abstract
Polytetrafluoroethylene (PTFE) is an excellent gasket material, chemically, but it has relatively poor mechanical performance. As a result, much effort has gone into improving the mechanical performance of PTFE-based gasket materials. Methods to improve mechanical performance include the addition of fillers (glass fibers, glass microspheres, silica, barium sulfate, carbon, etc.) and the manipulation of the microstructure (micro-cellular, expanded, restructured, etc.). These various forms of PTFE materials can have widely varying mechanical performance. PTFE materials that are chemically the same will have significantly different mechanical performance if the manufacturing process and microstructure are different. An example is the performance of amorphous, virgin PTFE sheet compared to fibrillated, expanded PTFE (ePTFE) sheet. The thickness of a gasket material is another structural difference that results in different mechanical performance.
This paper explores the difference in the mechanical performance of two common filled PTFE (fPTFE) materials that end-users often consider functionally the same at several industrially important thicknesses. The gasket materials are both barium sulfate-filled, restructured PTFE sheet materials. The mechanical performance of each material is compared for three thicknesses using the Hot Blowout Thermal Cycling test (HOBTC, ASTM WK61856 Rev 10-9-2020). [1] The thicknesses are 0.79 mm (0.031 inch), 1.60 mm (0.063 inch), and 3.18 mm (0.125 inch). The authors selected these thicknesses for performance review because of their usage in the industry. The thinnest, 0.79 mm (0.031 inch), is commonly used for instrument service. Very little performance data is publicly available on this thickness. The medium thickness, 1.60 mm (0.063 inch), is most commonly used in piping flanges. The thickest reviewed for this paper, 3.18 mm (0.125 inch), is commonly used for pressure vessels but also shows up in piping. Leakage testing according to the Room Temperature Tightness test (ROTT or ASTM F2836 Standard Practice for Gasket Constants for Bolted Joint Design) [2] was performed on the thinner 0.79 mm (0.031 inch) materials. HOBTC and ROTT testing was performed on an amtec TEMES fl.ai1 test fixture over the latter half of 2021 at the authors’ company. This data will demonstrate to the end-user how different the mechanical behavior can be of the same gasket material differing only in how thick it is.
Hydrogen Induced Cracking Susceptibility in the Heat Affected Zone of SA-508 Pressure Vessel Steel
Authors: Velasquez Joshua D. , Alexandrov Boian T. , McCracken Steven L. 
Published: November 2022

Abstract
ASME Case N-888, Similar and Dissimilar Metal Welding Using Ambient Temperature SMAW and Machine GTAW Temper Bead Technique, requires a 48-hour hold time before nondestructive examination (NDE) can be performed to ensure hydrogen-induced cracking (HIC) did not occur. The aim of this work is to assess and characterize the HIC susceptibility of SA-508 pressure vessel steel. The results from this study will be used to consider potential elimination of the NDE hold time requirement in Case N-888. The Gleeble™ thermo-mechanical simulator was used to recreate CGHAZ for five weld conditions; as-welded, post-weld heat treated (PWHT), and four single-reheat temperatures of 675 °C, 700 °C, 725 °C, and 735 °C to simulate temper bead welding (TBW). Metallurgical characterization revealed a tempered martensitic microstructure for all TBW and the PWHT conditions. The 735 °C TBW sample developed ferrite along the prior austenite grain boundaries. The single reheats to 675 °C, 700 °C and 735 °C reduced the as-welded CGHAZ hardness from 425HV0.5 respectively to 313, 298, and 278HV0.5. A fourth TBW condition was added at 725 °C to eliminate ferrite formation seen at 735 °C. The TBW at 725 °C produced a microstructure of tempered martensite with a hardness of 298HV0.5. The HIC susceptibility is being evaluated using the Delayed Hydrogen Crack Test (DHCT) developed at the Ohio State University. Samples of SA-508 steel with the five CGHAZ microstructural conditions are loaded at 90% of the base metal yield strength and simultaneously electrolytically charged with hydrogen. The HIC susceptibility is ranked by the time to failure (full specimen separation) and sustained mechanical energy.