bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Health Monitoring Using Time-Augmented Response Spectrum and Deep Learning
Authors: Aeba Takaki , Fukasawa Tsuyoshi 
Published: November 2024

Abstract
Institutions in the United States and Europe have highlighted the necessity for structural integrity assessment and issued guidelines for it. However, due to the lack of established standards for structural integrity evaluation, there is a demand for concrete methods. Techniques commonly used in structural health monitoring, such as Fourier and Wavelet transforms, are not physical quantities like acceleration and thus cannot be directly applied to seismic design. The response spectra used in seismic design lack temporal information. This paper proposes a time-frequency spectrum that is highly compatible with seismic design and includes temporal information. Furthermore, for the precision enhancement of structural integrity assessment, a deep learning model has been developed to determine structural integrity based on the multifaceted information provided by the proposed spectrum. The applicability of a structural health monitoring method combining these elements was verified using analysis and test data focused on plastic deformation. The validation results show that this method enables precise judgments, estimation of the time of anomaly occurrence, and visualization of the decision-making basis of deep learning.
Large Openings on Cylindrical Shell Subject to Axial Compression
Authors: Lu James , Millet Barry , Kirkpatrick Kenneth , Mosher Bryan , Hundl Jacob 
Published: November 2024

Abstract
Vertical vessels experience axial compression due to equipment dead weights, vessel contents and environmental loads. ASME BPVC Section VIII Division 2, Paragraph 4.5.17 provides rules for reinforcement of openings in cylindrical and conical vessels subject to axial compression. The rules outlined in the Code only apply to openings not exceeding 25% of the vessel diameter or 80% of the stiffening ring spacing. Openings exceeding these limits are required to be designed by analysis per Section VIII Division 2, Part 5. The rules in Part 4 of Section VIII Division 2 are quite restrictive for vessel manufacturers as a vessel smaller than 8’-0” in diameter with a 24” inner diameter manway would require a specialized analysis per the rules in Part 5 of the Code for which the majority of fabricators would require an outside consultant to perform, resulting in higher engineering costs for small diameter Division 2 vessels. Most of these vessels are not even subject to significant axial loads or bending moments. Pressure vessels designed to ASME BPVC Section VIII Division 1, European Standards EN 13445 and British Standard PD 5500 do not require opening designed for axial compression. This paper examines the effects of reinforcement for openings greater than the 25% of vessel diameter for vessels subject to axial compression and investigates the possibility of modifying the Code rules to increase the opening size limit to more than 25% of vessel diameters.
A Case Study on the Effects of Geometry and Stress Around Various Pin-Connected Members
Authors: Wiseman Phillip , Darade Animesh Anil , Sharma Timilsina Ayushma 
Published: November 2024

Abstract
Pin connections are commonly used in various applications revolving around civil and mechanical engineering. It is also an essential component in pipe support including both hangers and restraints, thus, understanding their current requirements is crucial. This paper involves a case study where different geometry of pin-connected members are examined on multiple stress conditions using finite element analysis (FEA) tools. Varied dimensions of pin and hole as well as multiple locations of the hole has been analyzed under various stress conditions. The stress distribution around the hole has been analyzed in this paper. The goal is to compare that stress distribution along the pin connected members, i.e., the hole, the pin, the connecting unit, and study which configuration would be suitable for which particular condition. The analytical data obtained using FEA and the stress distribution calculations has been used to compare and to select one of the most effective configurations. The primary purpose of the paper is to examine and optimize the effectiveness of pin-connected loads while considering their geometric restrictions. This optimization process involves finding the most efficient design for these members to ensure safety and reliability. The paper focuses on dimensional and stress regulations as per the ASME Boiler and Pressure Vessel Code and AISC 360 and takes into account the latest industry standards and guidelines to ensure compliance with current best practices. The paper investigates an analytical way to understand how the allowable stresses are handled in a certain geometric restriction and how the stress ratio is compared with geometric restriction of the pin, the hole and stress distribution around the hole.
Small Punch Tests to Evaluate the Tensile Properties of Highly Irradiated LYRA-10 RPV Model Steels
Authors: Naziris Frideriki , Adamech Marek , Marques Pereira Viviam , Martin Oliver , Bakker Theo , Kolluri Murthy 
Published: November 2024

Abstract
In the past few years, miniature testing techniques to evaluate the mechanical properties of structural materials of nuclear reactors have gained interest due to the limited number of irradiated surveillance specimens and strict safety regulations. One of such miniature testing techniques is the Small Punch Testing (SPT) method, which uses tiny discs to estimate mechanical properties such as tensile properties, fracture toughness and the ductile-to-brittle transition temperature of the examined material.
As described in the ASTM E3205 standard: Standard Test Method for Small Punch Testing of Metallic Materials, empirical relations are used to correlate the yield strength and the ultimate tensile strength to the SPT parameters determined from the investigated material. The validity of these empirical relations at high fluence irradiation needs to be further studied and understood to assess the potential applicability of the SPT technique for the evaluation of the effect of high-fluence irradiation in reactor pressure vessel (RPV) steels and for the implementation of this testing method in surveillance programs of existing nuclear power plants.
In this current work, SPT tests have been performed on six RPV model steels in the as-received and highly neutron irradiated state. These alloys were part of the joint NRG-JRC irradiation campaign LYRA-10 and resemble VVER and PWR RPV steels with tailored chemical compositions to study the synergetic effect of Ni, Mn and Si in the high fluence regime. The tensile properties of these materials prior and after irradiation are correlated with the SPT results and the shifts in SPT fitting parameter βp0.2 as effect of irradiation and chemical composition are studied to evaluate the effectiveness of this technique for screening of irradiation-induced hardening.
Circumferential and Off-Axis Crack Fatigue Growth Susceptibility in Buried Steel Pipelines
Authors: Lamborn Lyndon , Hogan James , Ferguson James , Skow Jason 
Published: November 2024

Abstract
While the industry generally discounts fatigue growth of circumferential and off-axis cracks in mainline pipe as being a credible threat, it has occurred. Three instances of girth weld and one instance of spiral weld crack fatigue growth are examined in this presentation and modeled for fatigue growth due to internal pressure fluctuation effects. Metallurgical findings for vintage girth weld fatigue growth are presented with potential root causality elements. A cutout indicating circumferential crack growth dormancy is likewise modeled to check model realism.
Using a surviving flaw approach and observed axial fatigue growth non-susceptibility downstream of pump stations, an off-axis flaw fatigue growth susceptibility methodology is proposed. Based on surviving flaw methods, stress intensity comparisons are employed to project the likelihood of fatigue growth in spiral weld cracks over a range of spiral weld angles. Sensitivity to superimposed axial tensile stress is projected based on the family of da/dN curves produced using the Walker theory.
A risk framework approach is proposed with baseline susceptibility considerations to assist operators to determine where fatigue growth of circumferential and off-axis cracking merits consideration. Potential risk treatment options are proposed with recommendations for future work.
Evaluation of Stresses in Saddle (Q-lip) Type Nozzles With Weaker Material Strength Compared to the Pressure Vessel Shell
Authors: Kuscu Koray , Singh Mandeep 
Published: November 2024

Abstract
ASME BPVC Section VIII Division 1 and 2 provide various design configurations for reinforcing nozzle openings in pressure vessels. One of these configurations is integrally reinforced saddle (Q-lip) type nozzle forgings, which are utilized when the nozzle to shell junction is required to be radiographically examined. These types of nozzles provide smoother geometrical transition at the nozzle to vessel junction, which results in reduced stress concentrations. In addition, these nozzles do not require a corner fillet weld, enhancing their performance if they are subject to cyclic (fatigue) loads. When the strength of the pressure vessel shell and the nozzle are similar, the nozzle to shell junction does not require any special consideration in the design. However, when the nozzle has a weaker material compared to the shell, connection between the two requires a refined design to address the local stresses. This paper aims to provide an insight to the stress distribution and potential design implications for such nozzle types and material combinations. Accordingly, various nozzle and pressure vessel geometries are designed using ASME Section VIII Code. Stresses are calculated using Finite Element Method at the vicinity of the nozzle to shell junction including the nozzle saddle transition and at the shell.
Parametric Study on the Vibration of Small-Bore Piping Branch Connections – Update
Authors: van Zyl Gys , Brodzinski Richard , Swindell Rob , Wally Gernot 
Published: November 2024

Abstract
In vibration service, small-bore piping connections, especially unsupported cantilever configurations, are associated with a high level of concern as potential fatigue crack initiation locations. In PVP2022-84119 the results of a study that was performed to characterize the relationship between vibration and stress amplitude of small-bore branch connections are presented. This work presents an update to the earlier study. The parametric finite element study was expanded to include contoured fittings and fittings with integral flanges and a different parametric distribution for the branch lengths was used. In the original parametric study, a random distribution of run pipe diameter and thickness and branch pipe diameter, thickness, and length was used to evaluate a few thousand different small-bore configurations. In this work the original distribution of parameters was compared with a typical site parameter set and the set of parameters used in this study was modified accordingly. Improvements were also made in the statistical analysis of the results, and the frequency dependance of a non-dimensional stress-to-velocity factor was investigated. Finally, the data set of natural frequencies obtained from the finite element analyses was used to develop optimized coefficients for an approximate equation to estimate the natural frequency from the geometry and mass properties of a small-bore piping connection.
Review of Standards for Liquid Hydrogen Storage Vessels
Authors: Li Keming , Guo Xiao , Shen Tao , Gao Yi , Han Yisong , Zheng Jinyang 
Published: November 2024

Abstract
Safe and efficient storage of liquid hydrogen is a challenge due to its extreme low temperature (20K). The development of standards is a key support for the construction of liquid hydrogen storage vessels. This paper presents an overview of current standards for liquid hydrogen storage vessels, including ISO 13985—2006 Liquid hydrogen — Land vehicle fuel tanks, CGA H-3—2019 Standard for cryogenic hydrogen storage, and three Chinses standards GB/T 40060—2021 Technical requirements for storage and transportation of liquid hydrogen, T/CATSI 05006—2021 Special technical requirements for static vacuum-insulated liquid hydrogen pressure vessels, and T/CATSI 05007—2023 Special technical requirements for transportable vacuum-insulated liquid hydrogen pressure vessels. Scopes of application including vessel types, pressure and volume are given for each standard. Materials for construction of liquid hydrogen storage vessels are presented, and the standard requirements and test data for materials used at cryogenic temperature are discussed. Designs of inner vessels, outer jackets, insulation system, support system, piping and safety accessories are summarized. Accelerations due to the movement of vessels, and calculation of inner tank and outer jacket thicknesses are mainly compared. Special requirements on forming, welding, heat treatment, and cleaning are presented. Routine tests including pressure testing, vacuum integrity testing, cold filling testing, and mass spectrometer leak detector testing, and type tests such as burst testing and thermal autonomy testing for fuel tanks, and normal evaporation rate and hold-time measuring are summarized.
Evaluating the Effectiveness of Bracing Designs in Reducing the Vulnerability of Small-Bore Piping Connections to Vibration
Authors: Wally Gernot , Bottomley Ian 
Published: November 2024

Abstract
Cantilever type Small Bore Connections (SBCs) in process piping are vulnerable to excitation from internal flow-induced turbulence (FIT). Current industry standard guidelines provide conceptual guidance for the design of SBCs where most of these guidelines arise from parametric numerical analyses carried out on unsupported cantilever-type SBC arrangements. As mitigation, the guidelines recommend the use of welded braces to increase the natural frequency of the SBC to a level where less vibration energy is available in the system to excite it, thereby reducing the dynamic stresses at the welded connections to acceptable levels. The available guidelines do not provide an approach to quantify the benefit provided by a particular welded bracing design or an assessment criterion against which to assess it. This paper seeks to address these issues as follows:
Welded bracing design evaluation for FIT: A parametric finite element study on thousands of different configurations was performed to determine how different welded bracing designs and parameters influence the natural frequencies of SBCs. The underlying parametric data set is based on design guidelines currently used by different engineering companies in actual processing facilities around the world and includes factors such as bracing concepts (2-way, 4-way), bracing profiles (flat-bar, angle bar) and overall bracing length. The study also provides a comparison of different attachment methods such as welded directly to the pipes (with and without reinforcement pad) or welded to a flange and how these methods affect the natural frequencies and consequently the fatigue performance of the SBCs.
SBC acceptance criteria: This paper also introduces the concept of a “cut-off frequency” for SBCs. It will be shown that if the natural frequency of a SBC exceeds this cut-off frequency it is very unlikely that a turbulence driven excitation, with single or multi-phase flow, can result in dynamic stresses on the SBC connection that will be sufficient to pose a fatigue threat. This part of the study utilizes the flow conditions gathered over several hundred real-life flow analyses and site assessments from which conservative “worst-case” flow conditions for single-phase flow and multi-phase flow were extracted.
Interpretation of the Progressive Deformation in Tube Plates
Authors: Billon François , Jourden Erwan 
Published: November 2024

Abstract
When we carry out a fatigue analysis in a tube plate and we exceed the 3Sm rule in the ligament between 2 holes, the question which then arises is: how to consider the elastic-plastic correction factor Ke?
The objective of our study is to propose an answer to the question by carrying out an elastic-plastic analysis of the tubesheet Elementary Representative Portion (ERP), made of 9 holes, by varying the stresses applied to the ERP and by analyzing, for different stress states and from the fatigue curve, the number of allowable cycles obtained with an elastic calculation and the number of allowable cycles obtained with an elastic-plastic calculation, in order to evaluate at this stage the consideration of the elastic-plastic correction factor.
Impact of General and Local Metal Loss on the API 579-1 Omega-Method Creep Analysis
Authors: Scano Lorenzo , Piccini Francesco , Palomba Salvatore 
Published: November 2024

Abstract
Creep and metal loss are typical and concomitant damage mechanisms of pressure equipment operated at high temperature. The phenomena influence and compete with one another: the loss of wall thickness acts as a stress-riser, fostering the inelastic strain accumulation due to creep; on the other hand, the stresses redistribute and relax due to the exposure in the creep range, especially in the case of localized corrosion.
API 579-1 [1] does not provide clear indications on how to deal with concurring damage mechanisms. For Level 3 assessments in the creep range a common and conservative approach is to carry out fully-corroded FEA, i.e., inelastic creep analyses in the ultimate condition of metal loss. In a previous part of the research [2], an FEA-based comparison was made with progressively-corroding finite-elements models for both general and local metal loss. The investigation was performed for a straight-section of a low-alloy pipe and the creep damage was calculated, at every integration step, according to the Larson-Miller method, as given by API 579-1 Part 10. The simplified approach was found conservative, in terms of creep damage, by a factor greater than 2 for uniform and greater than 1.4 for localized corrosion.
Given that the Larson-Miller theory is a stress-based methodology for accounting for creep damage, and considering the impact of stress redistribution and relaxation combined with the wall thickness loss, the API 579-1 Omega method (strain-based) was then taken into account in the inelastic FEA in the present work. The new investigation kept the same geometry and boundary conditions in terms of creep and corrosion rates in order to perform a direct comparison of the overall level of conservativism of the simplified approach when the creep is evaluated via the Omega method. The analysis shed also light on the notch-effect given by local metal loss and on its impact on the accumulated creep damage evaluated via stress or strain methodologies with and without ongoing corrosion.
Metallic Seal Ring Reusability
Authors: Payvar Reza 
Published: November 2024

Abstract
Metal-to-metal seals, exemplified by well-established designs like inverted T-shaped metallic seal rings, have emerged as preferred choices for both self-energized and pressure-energized sealing solutions. These seal designs find extensive application in clamp connections, compact flanges, or practically any metallic seal seat machined to provide the required diametrical interference and contact profile. By employing high-strength materials with elevated specified minimum yield strength, the reusability of these seals is substantially enhanced, consequently extending their operational lifespan from a sealability perspective.
Unlike the classical ratcheting model of Bree, which is based on the combination of primary membrane stress and alternating secondary bending stress in the same direction, ratcheting in this context may occur solely due to secondary stresses during the make-up (assembly) and break-out (disassembly) phases. This study centers on simulating the makeup and break-out cycles of these seals. The primary objective revolves around evaluating how key design parameters — specifically seal sizing and yield strengths — impact the distribution of plastic strain and the overall potential for reusability of the seal rings. In pursuit of this goal, a comprehensive assessment utilizes an elastic-plastic stress analysis method, as detailed in section 5.5.7 of ASME VIII Div. 2.
The study’s findings affirm that employing a minimum specified yield strength of 75 Ksi significantly enhances the reusability and operational lifespan of these seal types. This conclusion is in harmony with empirical insights gathered from various industries and is consistent with existing acceptance criteria, notably the stand-off value, which provides a quantitative measure of reusability potential.
ASME CC N-900 Revision Discussion (No.1) Effect of Triaxiality Factor on Allowable True Strain Amplitude
Authors: Shibukuwa Kenichi , Wen Jie , Takanashi Masahiro , Funasaki Kenji 
Published: November 2024

Abstract
In 2019, ASME Section III and JSME published a code case (ASME CC N-900[1]/JSME NC1 CC-008[2]) regarding seismic design codes for piping by using elastic-plastic analysis. As shown in PVP2023-107170[3] “Seismic Design Method of Crossover Piping Across Building Isolation Boundary”, while it would be clear that this code case using elastic-plastic analysis allows for a reasonable seismic design of the piping, there are few examples of actual seismic design works by using this code case. The reasons why the seismic evaluation method based on elastic-plastic analysis of piping has not been applied to actual design works include conservative strain-based criteria based on both Triaxiality Factor [TAF] and allowable true strain amplitude.
Therefore, this paper reports the studies result on the conservatism of allowable true strain amplitude of current ASME CC N-900 [1] based on the relationship between fatigue strength (life) and triaxiality factor [TAF] of pipe fittings, in order to establish a seismic evaluation method based on elastic-plastic analysis of piping in actual seismic design work.
A Failure Monitoring Method for Liquid Hydrogen Storage Tanks Based on Distributed Temperature Sensing and Digital Twin Technology
Authors: Li Chaoyuan , Yang Hong , Xue Jiacheng , Li Xiang , Zhang Haotian , Zhang Shouhua 
Published: November 2024

Abstract
Taking a typical high-vacuum-multilayer-insulation (HVMLI) liquid hydrogen horizontal storage tank as the object, a failure monitoring method of liquid hydrogen storage tank based on the temperature field of tank interlayer is discussed by combining real-time detection with numerical simulation. For the HVMLI structure, the outermost temperature of the insulation layer is calculated by the layer-by-layer heat transfer calculation method. Based on Fluent, the heat and mass transfer simulation of the tank model was carried out. Based on the MultiZone mesh division of the combination of tetrahedron and hexahedron, the energy equation, the standard K-epsilon turbulence model and the solar radiation model were selected to calculate the stable temperature field cloud map of the tank interlayer. Three common failure modes are simulated. The results show that compared with the normal working conditions, the outermost temperature field of the insulation layer will change significantly under the three failure modes. Combined with the conventional parameters such as the liquid level of the inner tank and the interlayer pressure, a multi-parameter fusion liquid hydrogen storage tank failure criterion is proposed, which can effectively judge the liquid phase leakage of the inner tank, the gas phase leakage of the inner tank, the leakage of the outer tank and the damage of the local insulation layer. Based on DTS technology, the safe and effective measurement of the temperature field on the outer surface of the insulation layer can be realized, and the twin model of liquid hydrogen storage tank driven by sensing data can be established to effectively judge the failure state.