bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparison Between Fatigue Capacity of a Subsea Connector Per S-N and Fracture Mechanics Methods
Authors: Sepehri Ali , Bansal Gaurav 
Published: November 2024

Abstract
Designing a high pressure, high temperature (HPHT) well is a complex and challenging task that requires careful planning, analysis, and execution. HPHT wells have pressures greater than 15,000 psi (103.4 MPa) and/or temperatures of more than 350°F (450K). These severe conditions pose significant risks and technical difficulties for drilling, completion, and production operations. To safely overcome the challenges in these operations, more advanced tools and new technologies are needed. In addition, because of the sensitivity of and potential impact on the environment, the industry is striving to homogenize the design and acceptance criteria. The Bureau of Safety and Environmental Enforcement (BSEE) requires equipment operating at high pressures and temperatures to pass a design verification analysis. This analysis includes structural, functional, and fatigue analyses, which are performed using finite element analysis (FEA) per ASME Boiler and Pressure Vessel Code (BPVC) Section VIII, Divisions 2 and 3, API STD 17G, and API TR 17TR8.
In service, HPHT equipment exposed to cyclic loadings (i.e., pressure, thermal, and external loads) is subjected to a fatigue screening to determine if a fatigue assessment is needed to calculate its life-cycle estimation for compliance with its functional specifications. If the HPHT equipment design does not satisfy the fatigue screening criteria described in ASME BPVC Section VIII, Division 2, it is deemed fatigue sensitive, and a more rigorous evaluation is required using design practices involving S-N fatigue curves (S-N design) or fracture mechanics (FM design), as recommended in API TR 17TR8 and per the methodology defined in ASME BPVC Section VIII, Division 3, API 579-1/ASME FFS-1, or BS 7910.
The objective of this study was to evaluate the fatigue service life of an HPHT subsea connector using the S-N and FM design methods. The fatigue life evaluation of the connector was performed with a finite element model using 3D geometry and elastic material properties. The S-N curves for steel forgings in air subjected to a high mean tensile stress from DNV-RP-C203 were used in this analysis. The material properties for fracture mechanics analysis were selected from BS 7910 and test data.
It was observed that fatigue capacity curves based on the S-N method following application of the design factors in API TR 17TR8 were more conservative than that based on the FM method in this study.
Design Application Method of Floor Response Spectrum Method Assisted by Time History Analysis for Multiply Supported Piping System
Authors: Yoshida Ayaka , Takayama Yoshihiro , Tsushima Toshiyuki , Hioki Hiroaki , Shudo Hiromichi 
Published: November 2024

Abstract
The independent support motion (ISM) response spectrum method is currently used in seismic analysis to calculate the response of piping systems subjected to independent excitations at several points of a supporting structure. This approach leads to considerable over estimation when the maximum responses by multiple excitations are combined by the absolute sum rule, while this may result in underestimation when the maximum responses by the multiple excitations are combined by the square root of sum of squares rule. Then authors have developed an advanced method of the ISM approach named SATH (spectrum method assisted by time history analysis), which was presented in PVP2020. In the SATH method, both floor response spectra and time histories of floor acceleration are used as independent inputs of support excitations. The maximum responses by multiple excitations are combined using correlation coefficients calculated by taking into account each time history of modal response due to independent inputs of support excitations. When the SATH method is applied to actual design using broadened FRS, the structural frequency uncertainty corresponding to broadened FRS should be considered in the calculation of correlation coefficients. The applicability of the SATH method to the structural frequency uncertainty was presented in ICONE2020. Furthermore, when piping systems are subjected independent excitations at several points of a supporting structure, the response of piping systems can be considered to have two different components. One is due solely to the inertia of the mass (the dynamic component) and the other is due to the time-varying differential motion of the support point (the pseudo-static component). Here, the dynamic component consists of two parts: the damped-periodic response (dynamic response) and the residual rigid response (high frequency response). Then authors have improved the SATH method to cope with above three responses (dynamic response, high frequency response and pseudo-static response), which was presented in ASME PVP 2023. Thus, since its presentation at ASME PVP 2020, the SATH method has been evaluated and improved several times and is now an appropriate method to use in design.
In this paper, the entire procedure of the SATH method, which combines the dynamic response using broadened FRS, with the high-frequency response and the pseudo-static response, is described as an actual design method. In addition, the advantages of the SATH method in design are clarified by comparing the response by the SATH method with that by the conventional method (the uniform response spectrum analysis method and the independent support motion response spectrum analysis method) for a three-dimensional piping system model subjected to independent excitations at several points of a supporting structure.
Fracture Toughness of Cold Formed Heavy Wall Plates in 2 ¼ Cr 1Mo ¼ V Low Alloy Steel
Authors: Palombo Marco , Doni Giorgia , Sandon Stefano , Fusari Fausto 
Published: November 2024

Abstract
The 2 ¼ Cr 1Mo ¼ V is widely applied for the design of high pressure and temperature equipment.
For large and heavy wall pressure equipment the cylindrical shell barrels can be carried either by forging or by plate forming to achieve the required dimensions.
Plate forming may have an impact on the material properties based upon temperature and deformation level for the involved plate thickness. Some specifications claim for a preheating temperature to be applied during plate forming of low alloyed steel. Such preheating in case of heavy wall plate thickness and inherent overall large dimensions has to be carried out in furnace with difficulties to keep the required temperature during the whole forming sequence and with inherent impact on the fabrication schedule. Eventually, a significant amount of gas consumption is envisaged.
A test campaign has been launched to investigate the real necessity of such preheating by forming of test plate coupons at different deformation levels with and without preheating. The base material selected was a low alloy 2 1/4 Cr 1 Mo Vanadium modified steel for which a preheating temperature of 177°C (minimum) is generally requested.
After forming, non-destructive examinations have been carried out followed by conventional mechanical test such as tensile strength and impact test aimed to investigate the resulting plate quality among the different forming conditions.
Material soundness can be impaired by existing flaws such as cracks, voids and metallurgical inclusions.
In order to better investigate the potential risk of crack propagation from existing defect under the applied stress, fracture mechanics tests according to ASTM E1820 have been carried out to characterize the possible different crack propagation behavior, by forming at room temperature and at preheating temperature of 177°C.
In this work the test campaign and the obtained results are presented, analyzed and discussed.
Probabilistic Fracture Mechanics Analysis Framework for the APAL Project
Authors: Bass B. Richard , Williams Paul T. , Dillström Peter , Tiete Ralf , Blasset Sebastien , Pistora Vladislav 
Published: November 2024

Abstract
The paper describes the development of a new probabilistic analysis framework designed to support the work scope of the Advanced Pressurized Thermal Shock Analysis for Long-Term Operations (APAL) Project. The APAL Project is funded in part by the European Atomic Energy Community (EURATOM) Work Program for Nuclear Safety. The primary objectives of APAL include the development of advanced probabilistic Pressurized Thermal Shock (PTS) assessment methods for reactor pressure vessels (RPVs) in the European Union (EU), including the quantification of safety margins for long term operation (LTO) and the development of best-practices guidance. The APAL Project goes beyond the state of the art by considering the uncertainties provided in the descriptions of RPV loading transients and by defining a margin based on a maximum allowable reference temperature (ART).
One of the required actions within the APAL Project is focused on defining an appropriate benchmark for probabilistic analysis of an RPV subjected to PTS loading. This benchmark will be applied when performing analyses using advanced probabilistic PTS assessment methods. Consensus APAL documents have identified specific modeling elements required to define and analyze this benchmark. Those elements include: (a) the Master-Curve distribution for fracture toughness, (b) capabilities for enhanced underclad crack analysis, and (c) specific correlations for fluence attenuation and reference temperature shifts due to radiation damage and embrittlement of the RPV wall. These capabilities were identified by the Probabilistic Structural Integrity of a Pressurized Water Reactor Pressure Vessel (PROSIR) Project, sponsored by OECD NEA/CSNI.
Several APAL participating organizations use the probabilistic fracture mechanics (PFM) computer code Fracture Analysis of Vessels – Oak Ridge (FAVOR), v16.1, exclusively for PTS analyses of RPVs; however, some modelling elements required by APAL are not included in FAVOR. Pursuant to the above new analysis requirements, one of the APAL participants, Oakridge Consulting International (OCI), Inc., implemented the above modelling capabilities into an advanced probabilistic analysis framework based on FAVOR, v16.1. The new PFM framework has been named Code for Advanced PTS Analysis for Long-Term Operation of RPVs (CAPAL), to distinguish it from the original FAVOR, v16.1, code.
This paper presents an overview of the CAPAL computational framework and the new capabilities implemented by OCI. Applications of the latter, described herein, demonstrate that CAPAL incorporates the specific modeling methodologies required to meet APAL’s objectives for performing advanced probabilistic analyses of the APAL-defined benchmarks focused on PTS integrity assessments of nuclear RPVs.
Influence of High Temperature Water on AISI 304 and ER 347 Regarding Their Threshold Value
Authors: Veile Georg , Grimm Michael , Weihe Stefan , Rudolph Jürgen 
Published: November 2024

Abstract
Welded joints are critical areas of components exposed to cooling water in NPP. For the improvement of the safety-critical fatigue design, an accurate analysis of the fatigue behavior in corrosive medium is essential. For this purpose, ER 347 weld material with its increased ferrite content and AISI 304 were investigated in medium conditions. Fatigue tests were carried out in air as well as in medium conditions of BWR at 240 °C, 70 bar pressure and 400 ppb dissolved oxygen and PWR at 300 °C, 100 bar pressure and 2.5 ppm dissolved hydrogen. Regarding fatigue tests in BWR conditions, possible contact corrosion induced by an extensometer in high temperature water is avoided by using a LVDT signal that replicated correlating data of strain-controlled fatigue test in air. To further improve implementation of the fatigue tests and reduce conservatism, the methods of past research projects were extended to model hardening and softening of fatigue specimen with an extended analytical equation for the LVDT signal. In the case of ER 347 the strain amplitude of 0.15 % proved to be within the so-called threshold value, where the influence of corrosive high temperature water is no longer detectable compared to fatigue tests in air stopped after 106 cycles. However, AISI 304 showed failure at this strain amplitude.
Research and Development of Three-Dimensional Isolation System For Sodium Cooled Fast Reactor Part 9: Evaluating Seismic Isolation Performance Through Seismic Response Analysis
Authors: Fukasawa Tsuyoshi , Somaki Takahiro , Yukawa Masaki , Hirayama Tomoyuki , Watakabe Tomoyoshi , Yamamoto Tomohiko , Okamura Shigeki , Miyazaki Masashi , Uchita Masato , Miyagawa Takayuki , Fujita Satoshi 
Published: November 2024

Abstract
This paper elucidates the isolation performance of a newly developed three-dimensional seismic isolation system through seismic response analysis. The seismic response analysis was conducted by incorporating the hysteresis characteristics obtained from static loading tests, for both each individual element and the assembled system.
To evaluate the design feasibility of the isolation system, static loading tests were judiciously conducted, considering a wide array of loading conditions, including beyond-design basis ground motions. Using the accumulated test data, a new analytical model was devised, capable of precisely capturing the hysteresis loops of each element. The hysteresis characteristics of the overall system were successfully elucidated through a static loading test on a half-scale model that assembled each element, with these results detailed in Parts 7 and 8.
The authors conducted a seismic response analysis, utilizing analytical models derived from the static loading test results of the half-scale model. This analysis incorporated the loading path obtained from 3D FEM analysis. The findings reveal that this three-dimensional isolation system, compared to horizontal isolation systems comprising rubber bearings and oil dampers, provides enhanced isolation performance against both design basis and beyond-design basis ground motions.
Concrete Cracking Modelling due to Reinforcement Bar Corrosion
Authors: Jarvis Wesley J. , Browning Kelvin M. , De Haan - De Wilde F. H. E. 
Published: November 2024

Abstract
Nuclear Power Plants (NPP) and research reactors built during the mid-20th century often have incomprehensive material characteristics for their concrete structures. This lack of quality records frequently leads to challenges when attempting to demonstrate safety during life extension projects or when specific modelling is necessary for plants SSCs when design regulations are updated with new or revised requirements.
In the framework of long-term operation (LTO), there is limited knowledge about ageing and the structural integrity of concrete structures. In order to increase the knowledge in the field of civil structures, this paper focuses on investigating the ageing mechanisms of civil structures at NRG, Petten, and using the previously calibrated chloride ingress model (PVP2023-105650) to determine expected internal pressure generation due to reinforcement bar (rebar) corrosion within a FEA model to predict concrete cracking.
In the most recent paper, PVP2023-105650, the modelling of ageing effects has been investigated by reducing material strength properties and developing a chloride ingress model calibrated to the HFR chimney. The model allows the predictions of rebar diameter reduction and internal pressure generation due to rust production. The FEA model developed under PVP2022-84008 was altered considering the reduced material properties and rebar diameter to gain a better insight into how it affected the determined concrete damage under a heavy drop impact.
The purpose of this research paper is to better understand the effect of internal pressure generation due to rust production and to allow the simulation of crack generation due to this degradation mechanism. The model has been calibrated to the results obtained from the HFR chimney. It is seen through the FEA simulation generated in Ansys that there is a close correlation to reality when modelling the calculated internal pressures using the previously developed chloride ingress model. The model is limited in its scope to the HFR chimney where the concrete information was obtained. Furthermore, the model must be recalibrated for each time period as the contact stiffness varies over time. The modelling method is also sensitive to a reduction of mesh size which is contrary to the majority of FEA models.
In the future, core samples of relevant HFR areas should be taken to determine the chloride concentration and rebar corrosion. This can allow for more data points for model calibration when simulating concrete cracking due to rebar corrosion.
Microstructure and Creep Performance of Wire Arc Additive Manufactured Grade 91 Steel
Authors: Wang Yiyu , Zhang Wei , Wang Yanli , Feng Zhili 
Published: November 2024

Abstract
In this work, creep performance of an as-built Grade 91 steel using wire-arc additive manufacturing (WAAM) was tested using a unique creep testing system integrated with in-situ high-temperature digital image correlation (DIC) strain mapping capability. The test results show creep lifetime of this as-built Grade 91 steel is much higher than that of Grade 91 steel weldments, even slightly above the mean lifetime of the conventional Grade 91 steels. In addition, highly nonuniform creep deformation in the as-built specimen was clearly captured by the DIC measurements, and correlated to the characterized inhomogeneous microstructures in multi-scales. Microstructure heterogeneities, including different martensite lath sizes, tempering degree of martensite matrix, and variations in precipitates, exist in two distinctive regions. A soft region, considered as the reheated “heat affected zone” (HAZ), has fine equiaxed grains, smaller martensite blocks, more precipitates, and a lower hardness. These microstructure features made these reheated HAZ regions more vulnerable to creep strength degradation, showing a larger creep deformation in the DIC measurements. A hard region with coarse columnar grains, less-tempered martensite matrix, and finer precipitates, exhibits a higher hardness and a better creep resistance. This study has clearly demonstrated that microstructure and creep strength variations at the meso-scale exist in the WAAM builds and should be carefully considered in WAAM process and material qualifications.
Simplified Fragility Assessment Method for Piping Systems in Seismic PRA
Authors: Ono Yohei , Nakajima Masato , Sakai Michiya , Shimazu Ryuya 
Published: November 2024

Abstract
Assessing the fragility of piping systems in nuclear power plants is time-consuming due to the many piping systems present. Applying elastic-plastic finite element analysis (FEA) becomes imperative when considering elastic-plastic deformation. This study introduces a simplified fragility assessment method predicated on the assumption of fatigue failure as the predominant mode of piping system failure.
The simplified fragility assessment method required pertinent design information. While it obviated the need for additional elastic-plastic FEM, it elastic-plastic deformation through a coefficient, denoted as Ke. The coefficient facilitated the consideration of plastic deformation. The simplified evaluation involved the computation of a time history strain amplitude derived from the response displacement of a single degree of freedom (SDOF) system subjected to the floor response acceleration of a piping system. Postulating that the maximum alternating stress intensity corresponded to the maximum displacement range enabled the determination of the time history stress amplitude. The time history strain amplitude was computed by dividing the time history alternating stress intensity by Young’s modulus. The usage factor was derived from the time-history strain amplitude and a best-fit curve for fatigue. The subsequent calculation of failure probability involved the usage factor, variabilities, and the capacity for fatigue failure. Systematic variation of the maximum floor response acceleration derived the assessment of failure probabilities for each acceleration level, a composite fragility curve and the median acceleration.
The developed method expedited the fragility evaluation of piping systems than the conventional elastic-plastic FEA. The median acceleration capacity, as determined by the simplified fragility assessment method, surpassed that obtained through the conventional method based on primary stress. It is more conservative than the result obtained through elastic-plastic FEA.
Experimental Study on Applicability of Triboelectric Film Sensors for Integrity Monitoring of Shear Bolted Joints
Authors: Wang Chu , Miura Nanako , Hiraga Motoaki , Masuda Arata 
Published: November 2024

Abstract
Many structures such as bridges, buildings, or automobiles use various joining methods such as screws, rivets, welding, gluing, and caulking to join members together. In particular, the shear bolted joints is widely used as a joining method that facilitates assembly and disassembly, while being accompanied by a troublesome problem of bolt loosening due to repeated shear force. In the previous study, we proposed a self-powered film-shaped triboelectric sensor made of inexpensive materials, being installed between the contact surfaces at the joint, to monitor the loosening of tensile bolted joints. The principle of the sensor is that it detects microscale relative motions between the contacting surfaces at the joint as the triboelectric induced voltage, when the integrity of the joint is deteriorated due to the decrease in the bolt’s fastening force. In this study, we apply our sensor to shear bolted joints. A sensor is designed, fabricated, and tested in a single-bolt shear joint subjected to lateral shear forces. As a fundamental experiment, we designed a drop test to apply a lateral impact to bolted structures, simulating the lateral loads experienced by bolted assemblies in real-world situations. Under various fastening forces of the bolt, we observed the sensor’s voltage output when subjected to the same impact force or lateral load. The analysis focuses on the relationship between the sensor’s voltage output signal, the impact, and the fastening force of the bolted structure.
Studies on Pipeline Polyethylenes in Hydrogen Gas Environments Using In-Situ and Ex-Situ Characterization Methods
Authors: Leveille Michael P. , Crain Christopher A. , Strange Nicholas A. , Banerjee Debasis , Nissen April , McDonald Anthony , Shin Yongsoon , Piontkowski Zachary T. , Menon Nalini C. , Simmons Kevin 
Published: November 2024

Abstract
Polymeric materials are commonplace in the natural gas infrastructure as distribution pipes, coatings, seals, and gaskets. Under the auspices of the U.S. Department of Energy HyBlend program, one of the means to reduce greenhouse gas emissions is with replacing natural gas, either partially or completely, with hydrogen. This approach makes it imperative that we conduct near-term and long-term materials compatibility research in these relevant environments. Insights into the effects of hydrogen and hydrogen gas blends on polymer integrity can be gained through both ex-situ and in-situ analytical methods. Our work represented here highlights a study of the behavior of pipeline polyethylene (PE) materials, including HDPE (Dow 2490 and GDB50) and MDPE (Ineos and legacy Dupont Aldyl A), when exposed to hydrogen by means of in-situ X-ray scattering and ex-situ Raman spectroscopy techniques. These methods complement each other in analyzing polymer microstructure. Data collected revealed that the aforementioned polymers did not show significant changes in crystallinity or morphology under the exposure conditions tested. These studies help establish techniques to study real-time effects of hydrogen gas on polymer structure and chemistry, which is directly related to pipeline mechanical strength and longevity of service.