bluuebunny/crossref_metadata_2025 huggingface dataset:
Acneiform lesions in a 57‐year‐old woman
Authors: Baczynski Alexandra , Sulejmani Pranvera , Medhus Emily J. , Bittar Julie , Amber Kyle
Published: November 2024

A 57‐year‐old woman on leflunomide with a history of chronic obstructive pulmonary disease and rheumatoid arthritis presented with multiple flesh‐colored to hyperpigmented dome‐shaped papules, scattered comedones, and underlying scarring on bilateral cheeks and chin. These dermatologic manifestations, laboratory evaluation, and punch biopsy led to a final diagnosis of acneiform or comedonal discoid lupus erythematosus (ACDLE). For patients with acneiform or comedonal lesions, ACDLE should be considered if the lesions do not improve with conventional treatment for acne vulgaris.
Cognitive and behavioral response of mosquitofish (Gambusia affinis) to environmental factors: Microplastics, predator cues, and detour design methods
Authors: Irwin Kyndal , Hathorn Grace , Gabor Caitlin R.
Published: November 2024

Urban stream syndrome is the collective term used to describe the physical and ecological degradation of streams draining urban lands that poses substantial threats to freshwater ecosystems. Among various consequences of urban expansion, microplastic pollution and shifts in predator–prey dynamics are prominent alterations to natural habitat that could impact the cognitive and behavioral responses of aquatic species. To explore how symptoms of urban stream syndrome impact the cognitive and behavioral responses of fish, we conducted two experiments using a delayed detour test to measure risk‐taking and inhibitory control in Gambusia affinis. In the first experiment, we hypothesized that G. affinis exposed to different concentrations of microplastics would show altered inhibitory control and risk‐taking. In the second experiment, we hypothesized that exposure to predator chemical cues during the detour task would alter inhibitory control and risk‐taking in G. affinis. We did not find significant differences in inhibitory control or risk‐taking in G. affinis exposed to microplastics or predator cues. We then compared the effect size and confidence intervals (CI) of these results with published results that used the same detour test to study inhibitory control and risk‐taking in G. affinis in response to different environmental conditions. Our investigations revealed that the CIs of the two studies presented here were larger than the CIs in the previously published studies. We consider potential changes to the experimental design that might have affected our ability to detect differences, such as the dimensions of the testing tanks. We also suggest extending the duration of the test to allow ample time for both exiting the starting chamber and solving the detour. We also propose considering the size and age of the species under study and adjusting the dimensions used in the detour paradigm design. Although our findings are specific to G. affinis, our results underscore the importance of considering aspects of the detour test design that are ecologically relevant to the study species when analysing cognitive and behavioral responses in fish. With our discussion, we contribute to the understanding of detour test methodologies and highlight potential ecological factors that could influence cognitive and behavioral outcomes.
Wettability of saliva substitutes across various denture base fabrication techniques
Authors: Mikhail Paul , Pesun Igor , Azpiazu‐Flores Francisco , França Rodrigo
Published: November 2024

Purpose

The present study evaluated the contact angles (CAs) of four denture base materials subjected to different surface treatments using deionized water and saliva substitutes.

Material and Methods

A total of 32 rectangular specimens were manufactured using four different denture base materials: heat‐cured compression molded Lucitone 199 (C), milled Lucitone 199 (M), Formlabs Denture Base RP (P), and SR Ivocap High Impact (I). The CA of the surface of the unaltered, mechanically polished, and sandblasted surface specimens was evaluated after the application of five saliva substitutes: Biotene, VEGA, Spry, Moi‐Stir, Dentilube, and ionized water. Ten droplet measurements were obtained for each group, with each droplet analyzed for advancing contact angle (ACA), receding contact angle (RCA), and the contact angle hysteresis (CAH) was calculated. The data of the experiment was analyzed using 2‐way ANOVA, (α = 0.05) with Tukey's test.

Results

CAH was demonstrated to have statistically significant differences among the denture bases (p < 0.05), with unaltered 3D printed exhibiting the largest CAH, followed by unaltered milled. The unaltered denture bases exhibited higher CAH than the polished, and there were no significant differences in CAH among the polished denture bases (p > 0.05). Sandblasting increased the ACA of the milled and conventional bases. The saliva substitutes exhibited differences in ACA, with Spry and VEGA having the highest ACA, and Biotene had the lowest CA of all the saliva substitutes evaluated.

Conclusion

The manufacturing methods of denture bases influences the CAH, while the chemical composition of the denture base specimens does not appear to affect CAH. Sandblasting increases the ACA for the milled and conventional groups. Saliva substitutes do impact the ACA. Drawing from previous research, it is hypothesized that a 3D‐printed denture base or sandblasting a milled denture base may offer greater resistance to dislodgement.
Characterization of DetaClad™ Interface With Simulated Weld Overlay Repair: A Positive Assessment for Cost and Time Savings in Equipment Lifecycle
Authors: Sarrat Olivier , Stolz Philipp , Wilson Chris , Delahanty Tim
Published: November 2024

In the context of equipment repair and refurbishment, in situ weld overlay on top of existing cladder is not a common practice. Concerns exist regarding the interface’s ability to withstand stresses induced by the weld overlay. This study aims to comprehensively characterize the DetaClad™ [1] interface and its behavior after simulating a weld overlay repair.

When considering weld overlay repair options, preserving the cladding emerges as a highly favorable choice. Weld overlay on top of the cladding offers a cost-effective, time-efficient, and prudent approach to refurbishing critical components. By retaining the cladding, the method minimizes disruption to the base material, preserving its integrity and essential mechanical properties. Moreover, this approach prioritizes safety by mitigating potential hazards during the gouging process.

The purpose of this research is to demonstrate that weld overlay build-up on top of DetaClad does not compromise the bond quality, nor the mechanical properties of the steel. The test parameters include analyzing the mechanical properties of the interface before and after welding, along with a detailed examination of the mechanical and structural properties of the base and cladder material. In addition, cross section macro and micro examinations are performed to gain valuable insights into their structural integrity.

This study demonstrates that weld overlay on DetaClad-cladded surfaces preserves the interface integrity and mechanical properties of the pressure boundary.
Comparison of Three Design Assessment Approaches for a 2-Liter Containment Vessel of a Plutonium Air Transport Package
Authors: Bignell John , Gilkey Lindsay , Flores Gregg , Ammerman Douglas , Starr Michael
Published: November 2024

Sandia National Laboratories (SNL) has completed a comparative evaluation of three design assessment approaches for a 2-liter (2L) capacity containment vessel (CV) of a novel plutonium air transport (PAT) package designed to survive the hypothetical accident condition (HAC) test sequence defined in Title 10 of the United States (US) Code of Federal Regulations (CFR) Part 71.74(a), which includes a 129 meter per second (m/s) impact of the package into an essentially unyielding target. CVs for hazardous materials transportation packages certified in the US are typically designed per the requirements defined in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PVC) Section III Division 3 Subsection WB “Class TC Transportation Containments.” For accident conditions, the level D service limits and analysis approaches specified in paragraph WB-3224 are applicable. Data derived from finite element analyses of the 129 m/s impact of the 2L-PAT package were utilized to assess the adequacy of the CV design. Three different CV assessment approaches were investigated and compared, one based on stress intensity limits defined in subparagraph WB-3224.2 for plastic analyses (the stress-based approach), a second based on strain limits defined in subparagraph WB-3224.3, subarticle WB-3700, and Section III Nonmandatory Appendix FF for the alternate strain-based acceptance criteria approach (the strain-based approach), and a third based on failure strain limits derived from a ductile fracture model with dependencies on the stress and strain state of the material, and their histories (the Xue-Wierzbicki (X-W) failure-integral-based approach). This paper gives a brief overview of the 2L-PAT package design, describes the finite element model used to determine stresses and strains in the CV generated by the 129 m/s impact HAC, summarizes the three assessment approaches investigated, discusses the analyses that were performed and the results of those analyses, and provides a comparison between the outcomes of the three assessment approaches.
Effect of Temperature on Hydrogen Assisted Fatigue Crack Growth Rate of an Austenitic Stainless Steel
Authors: Michler Thorsten , Varfolomeev Igor
Published: November 2024

The fatigue crack growth rate (FCGR) of austenitic stainless steel 1.4404 was measured in uncharged and in gaseous hydrogen precharged conditions, both as a function of temperature. At room temperature and ΔK < 40 MPa m0.5, the FCGR of gaseous hydrogen precharged 1.4404 is by a factor of about 5 higher compared to the uncharged condition. FCGR as a function of temperature revealed a broad maximum at temperatures between 293 and 333 K. The temperature of maximum FCGR does not correlate with the temperature of maximum loss of tensile RA, which is about 220 K. A simplistic interpretation based on the respective governing mechanism, HEDE for FCGR tests and HELP for tensile tests, is proposed.
Ultrasonic Testing in Lieu of Radiographic Testing: Application to ASME III Class 1 Nuclear Pressure Vessels in the Context of Rolls-Royce Structural Justification Expectations
Authors: Whitehead David , Rice David
Published: November 2024

Volumetric inspection of major welds with Radiographic Testing (RT) methods is typically required for nuclear pressure vessels designed and manufactured in accordance with Section III of the ASME Boiler and Pressure Vessel Code. A number of ASME Code Cases exist which allow the RT prescribed within certain Sections of the Code to be substituted with Ultrasonic Testing (UT). Of particular interest, Code Case N-659 allows the use of UT in lieu of RT during the construction of Section III - Subsection NB nuclear pressure vessels.

The use of UT in lieu of RT during the construction of nuclear pressure vessels has the potential to unlock several attractive benefits. Substantial reduction in radiological safety risks during construction can be achieved as the need for radiological sources is reduced, particularly for thick section welds where high power sources are required. Flexibility during vessel construction is also improved, allowing either UT or RT to be deployed based upon the availability of operational resource and shielded RT enclosures.

Rolls-Royce designs nuclear pressure vessels in accordance with the principles of the ASME Boiler and Pressure Vessel Code. In addition to the ASME Code, Rolls-Royce implements a structural integrity policy, which considers the UK Technical Advisory Group on Structural Integrity (TAGSI) four-legged safety case approach. This approach promotes defence-in-depth through four conceptually distinct arguments (legs), to construct a robust safety argument.

This paper discusses the application of the N-659 Code Case within the context of Rolls-Royce structural justification expectations, including consideration of the TAGSI four-legged safety case approach.
A Standard Form for Cyclic Plasticity Models Used With the ASME Section III, Division 5 Rules
Authors: Messner Mark C.
Published: November 2024

Recent work by the ASME Boiler & Pressure Vessel Code Committees has produced a new nonmandatory appendix to Section III, Division 5 providing guidance and approved constitutive models for the Section III, Division 5, Subsection HB, Subpart B design by inelastic analysis rules. This appendix, along with the associated Code Cases, includes approved material models for three Class A materials. A fourth model, for Alloy 800H, has also been created and is currently being reviewed by the code committees. Currently, all four of these material models has a different mathematical form. This complicates the process of implementing and applying these models. This work describes a single, standard model form that can describe the high temperature, cyclic behavior of all four materials with reasonable accuracy. Specifically, we describe the need to alter the standard viscoplastic flow rule used with the Chaboche model for cyclic plasticity in order to accurately describe both cyclic deformation and creep at the onset of the creep regime. We propose a Kocks-Mecking type flow rule that can describe both viscous creep, at low stresses, and nearly rate-independent deformation at higher stresses. This paper also provides the calibrated material coefficients for the four Class A materials and describes the process of training these parameters against the available test data.
Review of Original Calculations and pc-PRAISE Source Code Used to Develop ASME Code Section XI Appendix L Equivalent Single Crack Tables
Authors: Xu Steven X. , Glunt Nathan , Shim Do Jun , Stevens Gary L. , Scarth Douglas A.
Published: November 2024

ASME Section XI Appendix L permits the use of flaw tolerance procedures to determine the allowable operating period for operating plant components and piping subjected to cyclic loadings, providing NDE confirms that the location of interest has no flaw larger than allowed by the Acceptance Standards. The flaw tolerance analysis postulates a pre-existing flaw at the location of interest and calculates fatigue crack growth to determine inspection intervals necessary to assure that the fatigue-growing flaw can be detected before it exceeds the allowable size. To account for the possibility of multiple flaws coalescing and forming longer flaws during the fatigue crack growth, the postulated single flaw is assigned with an aspect ratio, known as the ESC (equivalent single crack) aspect ratio, based on the applied loading and material type.

As part of the activities undertaken by the Section XI Task Group on Appendix L, an effort was made to conduct a detailed review of the original calculations performed to develop the Appendix L ESC tables and the pc-PRAISE source code that was used for those calculations. This effort was necessary because the available Appendix L and pc-PRAISE technical basis documents do not contain all the necessary details to reproduce the ESC tables, and there were knowledge gaps that prevented a complete understanding of the original technical basis. This paper documents the review findings and their impacts on calculating ESC so that future improvements to Appendix L can be considered appropriately.
The Truth About Double Nutting
Authors: Thibodeaux Brett
Published: November 2024

There have been several studies performed that pertain to the use of two nuts to prevent self-loosening; however, these studies do not focus on accuracy of the final bolt load achieved nor do they quantify the proper procedure for ensuring an adequate jam is achieved. A thorough understanding of the interaction of the bolt elongation during this tightening process is necessary to avoid inadvertent reduction in ability to prevent self-loosening.

Testing is used to record the behavior of the nuts, bolts, and bolt load achieved during the tightening process while performing variations of double nutting assembly procedures to confirm the interaction between tightening methods, the resultant bolt load, and whether a jam is achieved.
Structural Analysis of a Light Water Small Modular Reactor Under Coolant Recirculation Conditions
Authors: Choi Dong-Hyeon , Chang Yoon-Suk
Published: November 2024

U.S. Nuclear Regulatory Commission proposes a method for evaluating integrity of reactor vessels (RVs) against pressurized thermal shock (PTS) via the code of federal regulation. Before evaluating the PTS, dominant locations of a postulated crack should be selected considering effects of thermal-hydraulic loads. Recently, with the development of a light water small modular reactor (SMR), substantial changes have made in the emergency core cooling system as a part of passive safety design that releases and condenses steam forming a pool outside the RV and recirculates it. The objectives of this research are to numerically investigate structural behaviors of the RV subjected to supercooling loads and significant pressure generated by external fluid. A typical coolant recirculation scenario was assumed based on the height of recirculation valve, temperature, and flow rate as variables. Firstly, the transient data of the coolant were derived through systematic computational fluid dynamics simulations for eight cases. Subsequently, accompanying structural analyses were performed to quantify stress states, which are used for selecting the crack location. Finally, sensitivity analyses were conducted to assess interaction of parameters and contribution of each parameter. As results, for the developing light water SMR, dominant locations and variables were determined under the coolant recirculation scenario, and relevant features were discussed.
Radial Displacement Measurement of Hydrogen Storage Cylinders Under Internal Pressure Based on Fringe Projection Profilometry
Authors: Ying Kaidi , Ma Li , Wen Ange
Published: November 2024

Composite gas cylinders, as an important hydrogen storage device for hydrogen fuel cell vehicles, require a hydrostatic test to ensure safe usage and service. However, there is a lack of a non-contact and efficient method to monitor the deformation of the gas cylinders during the hydrostatic testing. Thus, this paper proposes a radial displacement measurement method based on binocular fringe projection profilometry (BFPP) for pressurized hydrogen storage cylinders. We use BFPP as a highly sensitive three-dimensional (3D) shape measuring method, where the shape information that encoded in the deformed light pattern is acquired based on phase demodulation and coordinate reconstruction. Combining with 3D morphology measurement technology, internal pressure loading tests were conducted on a composite overwrapped pressure vessel with 55 Litre and 35MPa design pressure. Firstly, a large-field BFPP system was constructed to collect 3D point cloud data of the surface of the cylinder at different internal pressures. Then, a cylinder fitting based on the least squares method was used to obtain the radius. Finally, the difference of radius between pressure load steps was calculated, which indicates the radial displacement of the gas cylinder at different internal pressures. The measured result shows a good agreement with FEA calculations, where the radial displacement increase linearly with the increment of inner pressure. The error ranges from 2% to 18%.
Expanding the API 579-1/ASME FFS-1 Stress Intensity Factor Solution for a 360 Degree Surface Cracked Bar (KBSCL)
Authors: Altstadt Steven , Sarzynski Melanie
Published: November 2024

The current library of API 579-1/ASME FFS-1 2021 Fitness-For-Service stress intensity factor solutions includes round bars with various surface crack configurations. However, for all listed crack configurations, the stress intensity factor solutions are limited to axial membrane and global bending stress inputs. These stress inputs can be insufficient for some fitness for service applications. Considering this, a long-term effort is underway by the authors and others to expand the stress intensity factor solutions to accommodate generalized stress distributions for all applicable cracked round bar configurations.

In the current study, the Round Bar, Surface Crack – 360 Degrees, Through-Wall Membrane and Bending Stress (KBSCL) solution was independently investigated. The primary objective was to estimate stress intensity factors using parametric, linear elastic finite element models for a generalized stress distribution. The results were used to calibrate the respective influence coefficient values for a 4th order polynomial stress field in the radial direction. The study also assessed the API 579-1 three term weight function method, commonly used for arbitrary stress distributions, for the KBSCL crack configuration. Proposed updates to the global bending solution are also included. Finally, a comparison of the newly calculated influence coefficient values to previous results by Mangard (2017) was conducted, where the results are within a few tenths of a percent.
The Influence of Secondary Damage Mechanisms on the Suitability of the Single Specimen Unloading Compliance Technique to Assess the Fracture Toughness of SA508 GR. 4N and A533B Low Alloy Steel
Authors: Cooper Adam J. , Woodward Ronnie G. , Harrison Andrew W. , Wisbey Andrew
Published: November 2024

In the UK, high-integrity components for new nuclear reactors are subjected to extensive fracture toughness testing (FTT) qualification programmes to ascertain their resistance to ductile fracture and justify the toughness values used in safety case arguments. One cost-effective route to delivery of such programmes is the single-specimen FTT test method, which seeks to establish a complete J-integral resistance (J-R) curve from a single-specimen by calculating the incremental J-integral with increasing crack extension. This is achieved by monitoring the change in compliance associated with incremental crack growth during testing. Importantly, it assumes that a single primary crack is generated from the tip of a pre-existing fatigue crack during fracture toughness testing, the extension of which can be directly correlated to the change in compliance of the test specimen.

The study described herein follows an investigation into the suitability of the single-specimen unloading compliance (ULC) technique for characterising the J-R fracture toughness behaviour of an A533B pressure vessel steel. By comparing to data acquired from fracture toughness testing of SA508 Gr. 4N, it is shown that high toughness, low yield strength structural materials can, despite meeting the minimum allowable specimen size requirements of ASTM E1820-23, result in secondary damage mechanisms that are thought to be driven by global plasticity and a loss of crack tip constraint. This work compliments previously reported work on linking fracture assessment methodology to fracture toughness testing procedures.

This secondary ductile damage, revealed through metallographic sectioning, extends below the fracture surface and is orientated in the primary crack plane. These secondary ductile cracks were observed to not only originate in the crack tip blunting region but also in the ductile tearing region; in some cases, secondary cracks were observed to be on the order of mm in length running parallel to the primary crack. This work shows how the presence of this secondary damage influences the compliance measurements obtained during single-specimen analysis techniques. The work also demonstrates how these secondary damage mechanisms may not be captured when using a conventional multi-specimen fracture toughness testing approach, which is often credited with being a more reliable testing methodology over single-specimen techniques.
Evaluation of the API 579-1/ASME FFS-1 KSTC Stress Intensity Factors
Authors: Altstadt Steven , Leakey Scott
Published: November 2024

The API 579-1/ASME FFS-1 2021 (API 579-1) Fitness-For-Service stress intensity factor solutions for a sphere with a through-wall crack (KSTC) was investigated. Finite element models of through-thickness cracked spheres subjected to uniform crack face loading, linear crack face loading, and internal pressure induced stress fields were created and used to estimate stress intensity factors (K) along the various crack fronts, which were then used to establish influence coefficient values. Due to the extreme change in K near the surface vertices it is a common practice in engineering applications to extrapolate an effective K at the inside and outside surface locations based on a curve fit of the through-wall K variation. The method of extrapolation used for this assessment is similar to WRC 478, which established the basis for spheres and other through-thickness cracked shapes in API 579-1. The parametric space includes the current space covered in API 579-1 for KSTC, plus new higher ratios of sphere internal radius to thickness. The comparison of the newly calculated stress intensity factors to the existing API 579-1 KSTC values showed good agreement in some cases and appreciable differences for the remaining cases. The differences are likely due to improved mesh refinement and choices with the post-processing curve fitting strategy for the current results. The new influence coefficient values presented herein are recommended for fitness-for-service assessments that involve KSTC.
Validation of a New Failure Criterion for Burst Pressure Prediction of Corroded Pipes in Finite Element Analysis
Authors: Tao Gang
Published: November 2024

Burst pressure prediction of corroded pipes in Finite Element Analysis (FEA) has commonly adopted various forms of stress-based criteria by comparing the von Mises stress in the corroded ligament with a reference stress associated with the material’s true Ultimate Tensile Strength (UTS). However, many variations and inconsistencies exist in terms of how the von Mises stress is selected and what is the appropriate reference stress. These inconsistencies not only cause confusion in selecting the appropriate failure criterion, but also lead to challenges in accurate prediction of burst pressure for corroded pipes.

In light of physical burst test evidence, a plastic instability-based failure criterion was recently proposed for FEA prediction of burst pressure of corroded pipes. This new failure criterion is fundamentally identical to that used for predicting the burst pressure of uncorroded pipes. Based on the physical burst test results from a recent research program, this study critically examined the prediction performance of the plastic instability-based criterion and various stress-based criteria by statistical methods. The plastic instability-based criterion clearly demonstrated a more consistent prediction performance than the stress-based criteria. As an important implication of this study, the new failure criterion significantly improved the confidence of FEA prediction of burst pressure for corroded pipes in the absence of physical burst tests. The findings of this study also confirmed the ductile failure mechanism of corroded pipes and therefore demonstrated the importance of incorporating the strain hardening property in pipe corrosion assessment models.
Modified Pipe Connectors for High Pressure Pipe Joints
Authors: Sippy Haresh K.
Published: November 2024

In high-pressure [excess to 100 bar pressure] piping circuits in a refinery, petrochemical plants, fertilizer plants, power plants, etc., piping ends are connected with flanges/bolts/gaskets designed as per ASME B31.3 which is a process piping code. ASME B16.5/B16.20 is one of the popular removable flanged/gasketed joint arrangements However, these gasketed joints tend to leak at high pressures. Therefore, many end users are forced to weld piping ends [Refer Figure 2].

However, welding of piping ends reduces the flexibility of maintaining piping system as the end user is required to cut the pipe / weld for maintenance / modification and then re-weld the pipe. This is a very cumbersome and time-consuming activity as it involves on site welding which is very skilled work followed by local post weld heat treatment, and non-destructive examinations such as Ultrasonic examination or Radiographic examination.

Therefore, there is a need for a convenient and foolproof design of removable pipe connectors that can be used to connect two pipe ends easily and can be detached easily whenever required.

Some plant operators are now using clamped pipe connectors with T-shaped metal seals as an alternative to conventional ring flanges.

The work in this paper relates to an improved pipe connector design that involves a self-energized gasket combined with a blind cover, designed to work with the “Modified pipe connector” system. Additionally, it incorporates a mechanism that allows for online testing of the equipment without requiring its removal from the operational loop.

The improved pipe connector, design incorporates a specially designed self-energized Y-shaped sealing ring [Gasket] that provides multi-stage sealing such that:

- A first stage sealing is achieved by “when the clamp bolts are tightened, the hubs are drawn together by wedge action on the two clamps compressing the Y-shaped sealing ring.

- A second stage sealing is achieved by increasing the sealing pressure between the seal and hub faces thereby reinforcing the seal.

With the improved/modified pipe connector we aim to achieve a more reliable and leak tight joint.

Extensive analysis has been carried out to substantiate the above and the results of the same have been included in this paper.
Neural Network for Constitutive Modeling of Beam Structures
Authors: Ji Beilei , Mei Qipei , Taraghi Pouya , Adeeb Samer
Published: November 2024

Constitutive modeling plays a vital role in simulating the stress-strain behavior of structures within various engineering applications. Traditionally, constitutive models relied on experimental tests to accurately characterize the stress-strain relationship. In recent decades, there has been a significant increase in the development of advanced constitutive laws due to the high cost associated with testing. However, numerical computations based on advanced constitutive laws heavily relies on numerical integration which is time-consuming and computationally demanding. This leads to the need to develop an alternate approach. In this study, a neural network-based constitutive model using TensorFlow was proposed to capture the non-linear relationship between stress and strain in beam structures. A case study was conducted where the neural network-based constitutive model was implemented to predict the axial force and bending moment of the pipeline subjected to ground displacement, modeled as an Euler-Bernoulli beam with large deformations. The comparative analysis with traditional numerical integration schemes was pursued to assess the performance of the proposed model. The results showed a significant reduction in computation time when dealing with large data sizes. Additionally, the impacts of the training data samples on the applicability of the neural network constitutive model were investigated. The findings of this study support that the neural network-based constitutive model serve as a more efficient tool for extensive numerical simulations in the design and structural analysis of beam structures.
Flange Face Damages and Its Management for Plant Construction in Oil and Gas Industries
Authors: Yamazaki Koichi , Takahashi Atsushi , Kawai Masahiro , Tsuda Takahiro
Published: November 2024

Flange faces, in particular piping flange, often encounter mechanical and corrosion damages during the plant construction. Of the damages, mechanical one is easier to identify in terms of when it occurs and what causes it, and the responsibilities for a repair or a replacement is clearly attributed to which of the stakeholders, flange purchasers, flange manufacturers, stockiest, shipping companies, piping spool fabricators or piping erectors. For the corrosion damage, however, the responsibilities are often argued among the stakeholders because it is unknown when and why the damages occurred.

In order to avoid this meaningless argument and to prevent the corrosion, rust preventive coating is usually applied to flange faces for temporary protection by flange manufacturers due to easy application and anti-corrosion performance, however, the rust preventions selected and applied by flange manufacturers may not sufficiently prevent flange faces from corrosion during the plant construction. This is because there are many factors affecting corrosion to consider, such as site conditions and storage duration in construction sites. Due to these complicated factors, contractors for plant construction are facing with the difficulty of managing flange protection.

In order to solve the difficulty, this paper introduces and discusses that damage experiences, potential countermeasures against the damage and the example of flange face managements such as selection of rust preventive coatings and on-site preservation strategy.
Implementation of Non-Backing Gas GTAW Welding for Stainless Steel Process Piping in Oil and Gas Industries
Authors: Zhou Bin , Takahashi Atsushi
Published: November 2024

Gas Tungsten Arc Welding (GTAW) is a widely used welding process for joining stainless steel (SS) pipe work in oil and gas industries. For pipe welding of SS, back shielding by inert gas and its maintenance for the first few layers are required to obtain good weldability and quality of welds.

However, asphyxiation accidents of welders entering piping inside for repair by residual inert gas unfortunately are still reported, and unexpected remaining isolations inside piping for back shielding sometimes become concerns for obstructing fluid flow or damaging piping components.

To solve the concerns, some measures had been introduced to the industries. However, those measures cannot be widely applied due to lack of economical rationality such as necessity of special equipment and long training period of welders, and reduction of operational reliability with remaining slag and sticky spatters caught by radiography. To overcome those issues, non-backing gas (NBG) GTAW was introduced to apply SS piping welding by use of high silicon (Si) solid filler because positive results of weldability and quality of welds had been introduced in ASME PVP2022 [1].

This paper presents experiences of the first implementation of NBG-GTAW with high Si containing solid filler for SS process piping welding in oil and gas industries.
Fracture Toughness Tests on Western RPV Steels Using Small Scale Specimen Technique – Evaluation of Results
Authors: Obermeier Florian , Altstadt Eberhard , Hein Hieronymus , Das Aniruddh , May Johannes
Published: November 2024

In order to ensure continued safe operation of European nuclear reactors, it is necessary to solve specific issues that arise from irradiation induced reactor pressure vessel (RPV) embrittlement under long term operation. This requires an extension of the RPV surveillance programs to cover longer operation times than originally planned. The limited availability of surveillance materials poses a challenge for the feasibility of such programs. Among others, the use of the small specimen technology is a promising option to overcome the lack of materials. For example, a number of up to 16 sub-sized 0.16T-C(T) specimens (4 mm thickness) can be manufactured from two tested Charpy sized (10 mm × 10 mm × 55 mm) specimens, allowing a reliable determination of the reference temperature T0. Such Charpy sized fracture mechanics specimens are currently widely used in the RPV surveillance programs.

To support the acceptability for fracture mechanics testing of irradiated and unirradiated RPV steels using sub-sized specimens, a joined R&D project was launched partly financed by the German Federal Ministry for Economic Affairs and Energy. The partners are the technical University of Dresden / Helmholtz-Zentrum Dresden-Rossendorf (research institutes) and the Framatome GmbH (commercial nuclear company / supplier).

The objectives of the presented project are to identify a set of relevant RPV materials in unirradiated as well as irradiated conditions, to manufacture 0.16T-C(T) specimens and to test these specimens in accordance with the standard ASTM E 1921. The results shall be compared with results measured on standard sized fracture toughness specimens to demonstrate the transferability of the data. Moreover, the applicability of small scale testing under hot cell conditions will be demonstrated in view of manufacturing, pre-cracking procedure, measurements of crack-opening displacement and load line displacement.

The primary purpose is to demonstrate that the results measured on sub-sized specimens can safely be used in the safety assessment of RPVs. In addition, the results will establish a basis to assess results from international projects regarding sub-sized fracture mechanics specimens.

This paper presents the selected materials, the fracture toughness test results from small scale specimen testing, a comparison with results from standard sized specimen and fractography examinations. Results of a local approach analysis to support the interpretation of the test results are presented as well.
An Application of Random Response Analysis for Analyzing Vibration Fatigue Failures Due to Liquid Impingement Loads
Authors: Kummari Seetha Ramudu , Bifano Michael F. P. , Rinas Derek L. , Ishtiaque Hassan
Published: November 2024

Vibration fatigue failures of components or structures subjected to liquid impingement loads are common in oil and gas, and petrochemical industries. The impulse force due to liquid impingement is random in nature as the magnitude of the force depends on factors such as the way in which liquid breaks-up as it impinges, the variation in the droplet sizes, and the frequency of the droplet’s impingement. Often the designers estimate the impingement load as an equivalent static force based on the principles of rate of change of momentum. While such static equivalent load is a good estimate for the time-averaged force, the use of such force alone in the design analyses is unconservative. A better way to design the components for liquid impingement loads is to treat the impingement loads as random loading and analyze the components using random response analysis as discussed in this paper. In the random response analysis, the liquid impingement load is defined in a statistical sense; power spectral density (PSD) as a function of frequency. The stresses from the random response analysis are a measure of root-mean-square (RMS) stress. Such RMS stresses can be compared to an RMS stress limit that can be obtained by integrating fatigue damage defined using a design fatigue (S-N) curve. This paper discusses an application of the random response analysis for identifying the root cause of a pressure vessel’s internal deflector support cracking and the design changes to the deflector for protection against such vibration fatigue failures in the future.
Project FRACTESUS: Fracture Toughness Round Robin on a High Copper Weld Using Miniature C(T) Specimens – Results and Discussion
Authors: Obermeier Florian , Uytdenhouwen Inge , Altstadt Eberhard , Cicero Sergio , Sánchez Marcos , Echols John , Bonny Giovanni
Published: November 2024

The present FRACTESUS project aims to determine the effect of specimen size on the fracture toughness properties. Finite element models (FEM) are used to investigate the difference between large-size and miniature compact tension (MC(T)) specimens and quantitatively assess the resulting loss of constraint due to size reduction. The optimal range of usability of MC(T) specimens can therefore be determined and evidenced with experimental results. Large inter-laboratory testing is included in the FRACTESUS project to prove the repeatability and reproducibility of the small-scale testing of fracture toughness properties. Various materials relevant for most of the available reactor materials and irradiation conditions are investigated.

The experimental round robin on unirradiated materials has been completed by 13 different laboratories. The reference temperatures T0 obtained from MC(T) specimens by the different laboratories are compared to the one obtained from larger (mostly 1T-C(T)) specimens for six different materials. The considered materials are relevant for the nuclear industry and consist of four base (15Kh2MFAA, A533B LUS, A533B JRQ, A508 Cl.3) and two weld (ANP-5 and 73W) materials.

In this regard, the present publication will elaborate on the investigations and the results achieved during the round robin of the material ANP-5. The ANP-5 weld metal is a modified NiCrMo1 UP weld belonging to a 6-meter (236 inch) reactor pressure vessel (RPV) test weldment. This test weldment was manufactured and post weld heat treated by Klöckner Werke AG and is supposed to be representative for RPV weldments of 1st generation pressurized water reactors (PWR). The special feature of this material is the high copper content, which makes it particularly susceptible to irradiation-induced embrittlement.

In the framework of the FRACTESUS project the material was investigated according to the ASTM E1921 standard by five partners: SCK CEN, University of Cantabria, Helmholtz-Zentrum Dresden-Rossendorf, United Kingdom Atomic Energy Authority and the Framatome GmbH. Nearly 100 miniature C(T) specimens were tested to determine the transition temperature T0 and to compare it with the results of standard sized specimen. Within this ANP-5 test program two test series performed different than expected. A sharp transition from brittle to ductile without a distinct transition range was observed. The results of the test program and reasons for the unexpected material behavior will be discussed hereinafter.
Feasibility Journey – Fitness for Service Assessment of Pipeline Materials in Repurposing Existing Natural Gas Pipelines to Transport Hydrogen – Natural Gas Blends
Authors: Esmaeely Saba N. , Prewitt Thomas Joseph , Finneran Shane
Published: November 2024

Repurposing existing energy systems to low carbon sources is a necessary step toward decarbonization of the energy systems since it provides opportunities for time and cost-efficient transition overcoming the high cost of and public resistance to building new infrastructures. As part of such transitions, existing natural gas networks are being evaluated for compatibility with transporting hydrogen, either as hydrogen – natural gas (H2 – NG) blend, or as a steppingstone to potentially transport 100% hydrogen.

Considering change of service from natural gas to hydrogen, or H2-NG blend, requires evaluating the fitness for purpose of the system for the planned operating conditions to support a safe and reliable transition. This repurposing assessment should consider the potential impact of hydrogen on mechanical properties of the material (e.g. hydrogen embrittlement (HE)), which has been one of the main areas of investigation focusing on the boundaries where the existing materials are susceptible to hydrogen. Additionally, impacts to safety, risk, and integrity management should be assessed. However, there is a recognized lack of guideline on utilizing the existing data on HE toward re-defining the operating conditions and determining the remaining life of an existing pipeline when transitioning to H2/NG. The current paper discusses the challenges which should be considered in the Fitness-for-Service (FFS) assessment of an existing pipeline including, inline inspection (ILI) compatibility, flaw detection, reassessment/re-evaluation for FFS, revised remaining life, options for pressure reduction to enable H2 blending or transport.
Analyses of Stress Intensity Factor Solutions for Subsurface Flaws In Flat Plates
Authors: Li Suo , Li Yinsheng , Lu Kai , Lacroix Valéry , Dulieu Pierre
Published: November 2024

The stress intensity factor (SIF) solutions for subsurface flaws in flat plates are provided in Appendix A of ASME Boiler and Pressure Vessel Code Section XI. A part of the SIF solutions was initially provided in the 2015 edition. The solutions were obtained for the fourth order polynomial stress distribution base on the influence function method. The solutions were expanded in the 2021 edition for subsurface flaws near the surface of the plate. The additional solutions were obtained based on the J-integral from the elastic finite element analyses. However, recent investigations have found that there is a minor discrepancy in trend between the two sets of SIF solutions because they were obtained by using different numerical methods. Although the discrepancy is very small, the change in trend causes some difficulties in engineering applications. In this work, the SIF solutions are recalculated using the same numerical method based on the J-integral from elastic finite element analyses. The results are compared with the solutions in the current Section XI, RSE-M, and are finally cross-checked with the results obtained from an independent numerical model. The results are useful to eliminate the discrepancy in trend in the SIF solutions for subsurface flaws in flat plates in the current edition of Section XI.
Performance Analysis of 12MnNiVR High Strength Steel Plate for Large Oil Storage Tanks in China
Authors: Zhou Yunmeng , Chen Zhiwei , Jia Xiaoliang , Ji Fang , Cui Gaoyu , Li Xiang
Published: November 2024

Large storage tank is the most common, effective and mature container for storing oil. It plays an important role in national construction and national economic development. In the past, the steel plates used to make large oil storage tanks always imported abroad, which severely restricted the development of the industry. Many Chinese manufacturers spent several years on developing steels plate in order to promoting the development of the industry. 12MnNiVR is one of the steel for making large oil storage developed by Chinese manufacturers. In this paper, the properties of steel plate for large oil storage tank are studied. Through the comparative analysis of 12MnNiVR steel plate test data and enterprise standard performance indexes of major steel plate manufacturers from China and abroad, including chemical composition, yield strength, tensile strength, elongation after fracture and impact absorption energy, the results show that the performance indexes of 12MnNiVR steel plate produced in China are significantly higher than the requirements of GB/T 19189-2011, and most of the performance indicators have been stricter than the requirements of Japanese Standard JIS G3115-2005. The materials used for large storage tanks in China have completely replaced the imported materials and realized localization. The development of steel plate not only meets the development needs of large oil storage tank, but also improves the market competitiveness.