bluuebunny/crossref_metadata_2025 huggingface dataset:
Adipose tissue browning and thermogenesis under physiologically energetic challenges: a remodelled thermogenic system
Authors: Zhu Yupeng , Liu Weina , Qi Zhengtang
Published: November 2023

Metabolic diseases such as obesity and diabetes are often thought to be caused by reduced energy expenditure, which poses a serious threat to human health. Cold exposure, exercise and caloric restriction have been shown to promote adipose tissue browning and thermogenesis. These physiological interventions increase energy expenditure and thus have emerged as promising strategies for mitigating metabolic disorders. However, that increased adipose tissue browning and thermogenesis elevate thermogenic consumption is not a reasonable explanation when humans and animals confront energetic challenges imposed by these interventions. In this review, we collected numerous results on adipose tissue browning and whitening and evaluated this bi‐directional conversion of adipocytes from the perspective of energy homeostasis. Here, we propose a new interpretation of the role of adipose tissue browning under energetic challenges: increased adipose tissue browning and thermogenesis under energy challenge is not to enhance energy expenditure, but to reestablish a more economical thermogenic pattern to maintain the core body temperature. This can be achieved by enhancing the contribution of non‐shivering thermogenesis (adipose tissue browning and thermogenesis) and lowering shivering thermogenesis and high intensity shivering. Consequently, the proportion of heat production in fat increases and that in skeletal muscle decreases, enabling skeletal muscle to devote more energy reserves to overcoming environmental stress.

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Layer-Specific Properties of the Human Infra-Renal Aorta During Aging Considering Pre/Post-Failure Damage
Authors: Sokolis Dimitrios P.
Published: November 2023

There is little information on the layer-specific failure properties of the adult human abdominal aorta, and there has been no quantification of postfailure damage. Infra-renal aortas were thus taken from forty-seven autopsy subjects and cut into 870 intact-wall and layer strips that underwent uni-axial-tensile testing. Intact-wall failure stress did not differ significantly (p > 0.05) from the medial value longitudinally, nor from the intimal and medial values circumferentially, which were the lowest recorded values. Intact-wall failure stretch did not differ (p > 0.05) from the medial value in either direction. Intact-wall prefailure stretch (defined as failure stretch-stretch at the initiation of the concave phase of the stress–stretch response) did not differ (p > 0.05) from the intimal and medial values, and intact-wall postfailure stretch (viz., full-rupture stretch-failure stretch) did not differ (p > 0.05) from the adventitial value since the adventitia was the last layer to rupture, being most extensible albeit under residual tension. Intact-wall failure stress and stretch declined from 20 to 60 years, explained by steady declines throughout the lifetime of their medial counterparts, implicating beyond 60 years the less age-varying failure properties of the intima under minimal residual compression. The positive correlation of postfailure stretch with age counteracted the declining failure stretch, serving as a compensatory mechanism against rupture. Hypertension, diabetes, and coronary artery disease adversely affected the intact-wall and layer-specific failure stretches while increasing stiffness.
LMP and Omega Creep Testing of HPMA Centrifugally Cast Fe-Cr-Ni Alloys
Authors: Hau Jorge , Abdellatif Hussain , Park Neil
Published: November 2023

A creep test program was undertaken with six tube samples removed from a SMR furnace. The tubes are HP micro alloyed centrifugally cast Fe-Cr-Ni that contains Nb and minor amounts of Ti, Zr, W, and perhaps rare earth elements. Both LMP and Omega creep tests were performed. Initially, this type of material is inherently creep brittle but as soon as it is put in service, the high operating temperatures caused significant increase in creep ductility that occurred at the expense of decreasing creep strength. However, the impact resistance measured by Charpy tests remains as low as as-cast condition. This paper describes the material creep behavior of this alloy in the light of the Omega test parameters and shows the correlations found among all these factors that were measured, as well as with the LMP method.
Bridging Length Scales Efficiently Through Surrogate Modelling
Authors: Knowles David , Demir Eralp , Smith Mike C. , Yankova Maria S. , Vasileiou Anastasia , Rissaki Dimitra , Wilcox Paul , Kumar Dinesh , Mokhtarishirazabad Mehdi , Mostafavi Mahmoud
Published: November 2023

Safety sensitive industries are increasingly facing challenges such as reducing their environmental impact and bringing down their cost. Part of the solution to such challenges is economical use of assets while maintaining the safety level if not increasing it. Thus, more informed and reliable decision making on repairing or replacing key components is becoming even more important where a simple binary safe/unsafe choice is no longer desirable. Instead, a realistic assessment which inevitably would be probabilistic is needed. However, obtaining the required level of data to suitably underpin a probabilistic assessment can be prohibitively expensive as carrying out hundreds if not thousands of full-scale tests is no longer economically possible. In this work, we explore an alternative approach in which micromechanical characterisations, which due to their small scale, are more affordable, are carried out and informed a meso-scale model of the material behaviour. The meso-scale simulation, that is a crystal plasticity finite element model, is informed by the variations within the material microstructure thus returning a representative material response. The model variation can be estimated by machine learning algorithm such as polynomial chaos expansion thus returning material response variability in a sensible time-scale. The material variability, in turn, is input into a surrogate model of a process modelling, in our case welding simulation, to produce variability in a parameter important for assessment such as weld residual stress.
HDPE Piping Stress Analysis Using the CAESAR Software With ASME NM.1 and NM.3.3
Authors: Fathi Mehdi
Published: November 2023

This technical paper defines a consistent approach for the stress analysis of PE piping based on guidelines of ASME NM.1. It includes CAESAR II setup (as an example) for HDPE pipe stress analysis and determines the qualification criteria for PE piping stress analysis. Recently ASME published NM.1 for thermoplastic piping systems, however this standard (code) does not exist in the latest Caesar software V13 (most recognized industrial software for stress analysis). The user of this document could run the stress analysis of HDPE through Caesar software with any version of this software.

Define to how incorporate the correct allowable stress, service temperature, environmental factor, poison ratio, thermal expansion coefficient factor, appropriate stress code and apparent elastic modulus to meet the code cycles as well as how it will be implemented regarding the duration of sustained loading to have safe and standard design. Lastly addressing the proper stress intensification factor and load case combination to evaluate the stress analysis result.

This technical paper applied to Caesar II V13 (latest revision) and all the previous revisions of this software as well. To date none of the Cesar II version has the ASME NM.1 in their database but in this paper have tried to justify using other code to be used and analyze the PE pipe.
Technical Revisions of JSME Environmental Fatigue Evaluation Method
Authors: Asada Seiji , Nakamura Takao , Kamaya Masayuki , Takahashi Yukio
Published: November 2023

In Japan, environmental fatigue evaluation for LWR components is required in plant life management (PLM) by the regulator. The utilities are using JSME “Environmental Fatigue Evaluation Method for Nuclear Power Plants” (JSME S NF1). The first publication of JSMS S NF1 was the 2006 Edition, and it was revised in the 2009 Edition. Recently, the Subgroup on Fatigue Evaluation in the JSME Committee on Power Generation Facility Codes has developed three technical items for the JSME Environmental Fatigue Evaluation, and those have been approved by the Committee. Those revisions will be incorporated into 2022 Edition. The first one implements revised design fatigue curves. The second one revises the environmental fatigue life correction factor, Fen for PWR components. The third one is a Flaw Tolerance Approach for environmental fatigue evaluation. In this paper, the above three items are introduced.
Development of a Piping Qualification Methodology and Testing – Proposal Enhancement to ASME BPVC and B31 Certification
Authors: Josodipuro Irawan
Published: November 2023

Piping play important roles in pressurized static systems. In the oil and gas industry, for example, they are used to perform the process function, transmission and distribution. Given the role of piping which is subject to elevated pressure, temperature, and fatal accidents have occurred in the history of piping, it is important that piping end-users feel confident that the piping they procure meet the safety requirements. This paper presents a case study where there have been breakdowns in the qualification of piping being offered by piping suppliers to the industry that did not comply with industry standards which can adversely impact plant operations and personnel safety. The loss of piping supplier credibility is a concern that may rarely occur in mature economies but seem to be more prevalent in countries where qualification standards are either relatively new or nonexistent. To address this issue, the author presents a systematic approach that can be used to ensure that piping supplied to endusers in power, oil and gas industries in emerging countries meet the design requirements and standards they are required to meet. The process used to control the manufacturers begins with a qualification plan which each supplier has to establish its product line. Following compliance with the qualification plan, a criticality matrix is introduced to the manufacturers that classify the criticality of each piping type in the system and the associated qualification program(s) that the manufacturers need to meet. The validation with an established program has shown some merit and could be applied to all manufacturers in emerging countries to ensure consistency. The details of the qualification program used and how the process is evaluated are covered in the body of the paper together with examples of how the process has worked.
Application of Robotic Digital Radiography in Oil & Gas and Refinery Projects
Authors: Sano Teruaki
Published: November 2023

In the Oil and Gas refinery industry, over 300,000 films must be handled in a single mega-sized project. To reduce the workload needed for this film work, robotic digital RT (DR) was used in some cases, instead of film RT. As a result, work efficiency was improved because the RT exposure time for DR is shorter than that needed for film RT and the time-consuming work needed for changing, handling and developing film was eliminated.
Organization and Basis of ASME Section XI, Nonmandatory Appendix Y, “Crack Growth Rate Curves”
Authors: White Glenn , Fuhr Kevin , Udyawar Anees , Scarth Doug , Shim Do Jun
Published: November 2023

Nonmandatory Appendix Y of ASME Section XI presents relationships for fatigue crack growth rates and stress corrosion crack growth rates for austenitic stainless steels, ferritic steels, and nickel alloys for use in analytical evaluations. These crack growth rate equations are needed to predict the crack growth rate for the applicable cracking mechanism, material, and environment. The cracking mechanisms addressed are fatigue in air, fatigue in water environments, stress corrosion cracking, and irradiation-assisted stress corrosion cracking. Boiling water reactor and pressurized water reactor water environments are included. Nonmandatory Appendix Y was introduced within the 2021 Edition of the ASME Boiler and Pressure Vessel Code as a consolidated repository for crack growth rate equations. A second objective of Appendix Y is to standardize the nomenclature, physical units, and figures associated with the various crack growth rate relations. Changes anticipated for the 2023 Edition include moving all crack growth rate provisions from other nonmandatory Section XI appendices (including Nonmandatory Appendices A and C) into Appendix Y. This paper describes the organization of the 2023 Edition of Appendix Y and documents the source of each equation. Also tabulated are the active Section XI Code Cases that include crack growth rate equations, as well as the most recent status of acceptance by the U.S. Nuclear Regulatory Commission.
Multi-Axial Stress Creep Consumption Part I; Testing and Validation of Ex-Service 347 SS
Authors: Suzuki Teppei , Ishizaki Yoichi
Published: November 2023

A cracking damage was found in 347SS flange neck operated at about 520 deg. C after long term operation. In previous report presented in PVP2019-9304, it was well explained by creep damage from FEM analysis using isochronous curve based on API 579/ASME FFS-1 MPC Omega method. Following our previous paper, specimens were obtained from the replaced flange operated for 4 years. Using those specimens, destructive testing and remaining life assessment were performed to validate the analysis.

As a result, specimens from the flange neck showed relatively short rupture life, compared to those from other locations. MPC Omega method along with adjustment factors derived from testing resulted in remaining life of 3.1 to 6.8 × 105 hrs. at average operating condition. In consideration with temperature variation during operation, remaining life is estimated to be 2.6 × 10-5 hrs., indicating 10 % life consumption at the time of taking sample. Life consumption estimated by FEM analysis is rather conservative but is comparable within factor of 2 when average strength is applied for the evaluation.

Since the estimated stress conditions and test conditions are close to 0.2% proof stress of the material at this temperature range, significant primary creep strain was observed in the tests, that can cause some conservativeness in remaining life by the FEM analysis.

While above, Larson Miller Parameter method also adjusted with rupture test data agrees with MPC Omega method on the assumption of uniaxial tension. However, it gives less-conservative life under the multiaxial stress conditions. Effect of multiaxial stress on creep life is more significantly observed in MPC Omega method, especially when stress ratio is higher.

In this part I of two papers, the detail of creep test will be presented and discussed. In part II, current creep temperature limit shown in API579-1/ASME FFS-1 Part 4 Table 4.1 will be discussed and suggest an upgrade of creep temperature criteria based on the multi-axial creep model we learned through studies.
Present Status of the Fractesus Project: Round Robin on Unirradiated Materials
Authors: Bonny G. , Altstadt E. , Arffman P. , Cicero S. , Obermeier F. , Petit T. , Swan H. , Chaouadi R. , Gaganidze E. , Hargitai B. , Kolluri M. , Kopriva R. , Rozsahegyi P. , Serrano M. , Spätig P. , Uytdenhouwen I. , Wilcox H. , Yamamoto M.
Published: November 2023

The present paper provides a summary of an inter-laboratory round robin on the fracture toughness testing and Master Curve application on unirradiated materials. First, a validation exercise was performed on the analysis of a given force-displacement curve. Then, a validation exercise was performed on the application of the Master Curve procedure on a given data set of fracture toughness results. Finally, the preliminary results of the Master Curve application on mini compact tension (MC(T)) specimens by 13 different labs on six different materials (four base materials and two welds) are presented. The validation exercise on fracture toughness data evaluation showed the need for a uniform conversion from front face displacement to load line displacement. The validation exercise on application of the Master Curve approach to obtain the reference temperature proved the equivalence between the T0TEM software and in-house developed softwares. The inter-laboratory round robin showed the equivalence between T0 obtained by MC(T) and larger specimens, except for A533B JRQ and 73W. The reasons for the deviations of A533B JRQ and 73W are under investigation. As a general comment, it can be stated that the results from MC(T) specimens often indicate material inhomogeneity as compared to the result from larger specimens. This is likely the consequence of the small sampling volume of the MC(T) specimens.
Experimental and Numerical Investigations on the Relaxation Behaviour of Power Plant Flange Connections Under Steady State and Transient Conditions
Authors: Kettler Kevin , Klenk Andreas , Weihe Stefan
Published: November 2023

An essential part of today’s power plants are flanges, for example as connection between turbine housings and pipes. Which allows revisions, inspections and maintenance measures. Ongoing changes towards higher amounts of renewable energy sources leading to higher demands in flexibility to counter balance weather-related fluctuations. This flexibility leads to changing load types with more frequent warm and hot starts, causing uncertainties for the design and the determination of maintenance intervals of bolted flange connections.

In this context, results of a recently finished research project and ongoing numerical investigations are presented. Tests on a model of an IP turbine flange under near-to-service loads such as internal pressure and temperature are carried out using a test rig allowing heating on the flange’s inner surface. Concerning different influences on the stress relaxation behavior results are shown for tests with martensitic and nickel-based bolted joints. The total test time of 5000 h for each bolted joint consist of 2000 h under steady state conditions and 3000 h under transient conditions. Comparisons of the results with the martensitic and nickel-based bolted joint show an opposite creep strain distribution in the bolt and flange. In addition, a significant influence of the already existing creep deformation from previous load periods can be observed. Comparative simulations with a modified Graham-Walles creep model are carried out. The results confirm the differences in creep behavior with both bolted joints and reproduce the observed influence of the previous creep deformation.
Effects of Fatigue Parameters on Fatigue Crack Growth Rate of Pipe Steels and Girth Weld
Authors: Park Dong-Yeob , Liang Jie
Published: November 2023

Oil and gas pipeline steels and welds are subjected to a wide variety of cyclic loadings: internal pressure variation, pulsation of gas pressure resulting from the cyclic operation of a reciprocating compressor at a gas compressor station, internal flow-induced vibration resulting from the turbulent flow within the pipe, vortex-induced vibration of a free-spanning section exposed to air (wind) for aboveground pipelines or water for water-crossing pipelines, and cyclic thermal stresses developed by significant changes in temperature due to seasonal changes or changes in operating temperatures. These cyclic loadings are very variable and complex. Considering the fatigue situations, a better understanding of the effects of fatigue test parameters on fatigue behaviors of pipeline steels and welds is required. Hence, in this study, the influences of fatigue test parameters on the Paris law coefficients were studied for pipeline steels and welds. It was analyzed for pipe steels of X65∼X100 and a girth weld of X70. Influences of material strength, crack orientation relative to the pipe axis, and frequency in the range of 1∼30 Hz were insignificant. It was found that the coefficients a1 and b2 of the m-ln(C) relationships linearly relied on the load ratio. The constants (α1, β1, α2, and β2) of these linear relationships between R-ratio and a1 (and b2) were determined for pipe steels.
Fit for Service Evaluation of LDPE Tubular Reactor Tubes Exposed to Severe Decomposition
Authors: Abdul Hamid Ahmad Hassan , Abdul Rahim M. Syukri , Mamat Alias , Mat Ibrahim B. , Kadir Alias
Published: November 2023

The low density polyethylene (LDPE) tubular reactor tube is fabricated from a material with extremely high fatigue strength. During severe runaway decomposition reaction, the decomposing gas rapidly heats up the reactor tube bore surface to a temperature exceeding the austenitizing temperature of the steel (AISI 4333). Subsequent quenching by the incoming colder gas from the opening of the hydraulic safety blow-off valve hardens the bore surface. The fatigue life of the reactor tube can be negatively affected by the presence of the hardened layer. A maximum limit of 2 mm for the depth of hardening is specified in the operating manual for safe operation. A hardness test is conducted on the internal surface cross section of the lens ring (gasket connecting the two high pressure tubes) to establish whether the hardening has exceeded the 2 mm depth as a result of decomposition. Due to differences in chemical composition between the reactor tube and lens ring, a correlation between the depth of hardening of the lens ring and reactor tube is investigated. The remaining life of a reactor tube with a 3.4 mm depth of hardening was predicted through experimental fatigue cyclic test approach. Results of the prediction suggested that the depth of hardening of the tube was close representative of the hardened lens ring, while the experimental cyclic fatigue test suggested that the 3.4 mm hardening depth of tube could endure a significant numbers of pressure cycles before the tube fails (i.e. a through-wall crack that leaks).
How to Qualify Gaskets for Low Stress Flanges
Authors: Phan Cuong , Norman Dale
Published: November 2023

Many applications use cast-iron, glass lined, or fiberglass reinforced plastic (FRP) flanges. These flanges usually have limitations with the amount of clamp load that could be generated for sealing and require special gaskets that have a low seating stress. There are a variety of these gaskets in the market. These seals have typically validated their design through standard testing such as DIN EN 13555, and ASTM F2836-18. However, these standards compress the gaskets many times (10x+) beyond the limited maximum allowable clamping load of these flanges. A concern has been raised regarding if the test method might not be applicable to the real-world conditions, as the gasket stresses are so much higher. By reviewing ASME Section X - Fiber-Reinforced Plastic Pressure Vessels, and ASTM D5421 - Standard Specification for Contact Molded “Fiberglass” (Glass-Fiber-Reinforced Thermosetting Resin) Flanges, we are suggesting a low-stress-gasket leakage test by modifying the standard EN 13555 standard leakage test, by applying 20 percent of the standard loads required in each step, and adjusted the test pressure to the common pressure for FRP flanges, of 10 Bar. The paper will provide end-users with data from the modified test method and show the comparison on the leakage performances as it pertains to low-stress-gasket applications.
3D Metrology Analysis of Structural Damages on Type B Shipping Container Compared to Predicted FEA Results After Completion of NCT and HAC Regulatory Testing
Authors: Nogradi Paul , Martinez Oscar , Adeniyi Abiodun , Lowe Lance , Whittenbarger Ross , Fisher Ryan , McLaurine Austin
Published: November 2023

Packages used to transport Type B quantities of radioactive materials must meet normal conditions of transportation (NCT) and hypothetical accident condition (HAC) requirements as defined in Title 10 of the US Code of Federal Regulations, Part 71.71 and 71.73. Evaluating package designs to these criteria typically involves a combination of analysis and physical testing. These required physical tests include free drop, crush, puncture, penetration, compression, vibration, water spray, water immersion, and thermal tests which result in cumulative structural damages that must be evaluated and measured for comparison with data obtained from modeling and other specified standards.

This paper describes a comparison of the structural dimensions of a Type B package that has undergone a series of NCT and HAC tests to the finite element analysis (FEA) model. Dimensional data of the Type B package test unit (TU) was collected using a high-quality 3D scanner. This scan data was then analyzed in a CAD environment to extract the structural damage dimensions that the package experienced. The scanned data was finally compared to the corresponding structural damaged area predicted from the FEA model.

Results obtained from the comparison of the 3D scanned package to the LS DYNA results showed small differences in the diametric and localized impact dimensions. However, most of the dimensions did not vary significantly. These discrepancies were most likely the result of slight variations in the impact drop angles of the physical NCT and HAC tests, whereas the FEA results were created in a perfect orientation.
Assessment of ASTM A723 Steel for Constructing Impulsively Loaded Vessels
Authors: Gibson Joshem , Mueller Joshua J. , Spernjak Dusan
Published: November 2023

An alternate material for thick, e.g. greater than ∼6 inches (152 mm), non-welded Explosive containment vessels (ECVs) cover forgings was investigated. ECVs are used to partially or fully contain the detonation products of explosives. Uses of ECVs include containment of suspect luggage at airports, bomb disposal, containment of dynamic experiments, and disposal of chemical munitions. The impulsive loading and dynamic response of ECVs necessitates the use of materials with high strength and high toughness to prevent ductile exhaustion and brittle fracture. Design rules for impulsively loaded vessels (ILVs), applicable to ECVs, were introduced into Section VIII, Division 3 of the ASME BPVC Code through Code Case 2564 in 2008. In 2019, the ILV design rules were incorporated into Section VIII, Division 3, and Code Case 2564 was annulled. Section KM-4 of Section VIII, Division 3 includes approved materials for vessel fabrication; however, many of these materials either do not exhibit the requisite mechanical properties for ECV applications or lack corresponding published mechanical testing data necessary for ECV design. Another compounding factor is the new guidance in Section KM-234.1 (ASME BPVC Section VIII, Division 3, 2023), which requires Charpy V-notch (CVN) testing 60 °C (108 °F) below the Minimum Design Metal Temperature (MDMT). For many applications, this will require ECV construction materials to exhibit high toughness at low temperatures. In the present study, ASTM A723 steel forgings have been investigated as a candidate material for ECV construction. Mechanical property data from industrially produced forged disks are presented including full CVN temperature-transition curves and tensile test results. Additionally, insight is provided on the effect of tempering temperature on mechanical properties of A723 Steel.
Constraint Effect on Fracture in Ductile-Brittle Transition Temperature Region (Report 3)
Authors: Hojo Kiminobu , Hirota Takatoshi , Nagoshi Yasuto , Fukahori Takuya , Sakima Kimihisa , Ohata Mitsuru , Minami Fumiyoshi
Published: November 2023

In order to predict fracture behavior in the ductile-brittle transition temperature (DBTT) region of a structure with low constraint, a plastic constraint correction coefficient χ was proposed. It was defined as a ratio of KJ of a fracture toughness specimen to KJ of a reactor pressure vessel with a specific flaw shape with the same Weibull stress level, and it was given as a function of a shape factor of the Weibull distribution for the Weibull stress, and Ry, yield strength/ultimate strength. The Weibull stress was calculated based on the original Beremin model even in the DBTT region because no ductile crack initiation was confirmed by the RPV model under the four representative pressurized thermal shock (PTS) transient. The coefficient χ was proposed for a simplified facture evaluation to predict an accurate fracture behavior under pressurized thermal shock. In order to introduce χ to the codes, a simplified structural FE model, a flat plate model, was applied. After confirmation of conservativeness of the flat plate model and unirradiated material on χ, the coefficient χ was prepared for a draft standard of the Japan Welding Engineering Society, which was to be extended to other codes and standards, such as ASME Sec. XI, JSME. A main structure of the draft standard was also shown.
Comprehensive Prediction for Temper Embrittlement of Hydrogenation Reactors in Long-Term Service Condition
Authors: Liu Juanbo , Han Zhiyuan , Kang Haoyuan , Chen Sheng , Song Libin , He Meng
Published: November 2023

As critical pressure vessel equipment, hydrogenation reactors are widely used in the petrochemical industry and coal industry. Temper embrittlement, especially under long-term service conditions, is the most important damage mode for hydrogenation reactors. Currently, temper embrittlement in the API 579 (American) and GB/T 36669.1 standards (China) is correlated with embrittlement sensitive X and J factors based on steeping-cooling experimental data. Obviously, service conditions, including operation pressure, temperature and service time have significant effects on temper embrittlement, which should be further considered in the correlation. Besides, from the physical quantity dimension perspective, the dimensions of current prediction correlations for temper embrittlement are inconsistent. Considering the material properties (X and J factors), dimensional features (wall thickness) and service condition (operation pressure, operation temperature, service time) of reactors, this study systematically collected the actual service data in the literatures to propose a comprehensive prediction correlation for temper embrittlement. The parameters related to temper embrittlement are further correlated with non-dimensional numbers to maintain the consistency of physical dimension. The proposed correlation is validated with engineering experiment data, and the results demonstrate that the prediction correlations agree better with actual situation than previous correlations. This study will facilitate accurate prediction for temper embrittlement of hydrogenation reactors in long-term service condition.
Convolutional Neural Network Models for Reconstruction and Sizing of Three-Dimensional Metal-Loss Defects in Oil and Gas Pipelines Based on Magnetic Flux Leakage Signals
Authors: Shen Yufei , Zhou Wenxing
Published: November 2023

In this study, a three-dimensional nonlinear finite element magnetostatic model is developed in the commercial package COMSOL Multiphysics (Version 5.6) to simulate magnetic flux leakage (MFL) signals for corroded pipelines. A large number of parametric finite element analysis cases covering wide ranges of locations and sizes of corrosions defects idealized as semi-ellipsoidal-shaped are used to produce the magnetic flux density signals. The white noises characterized by different signal-to-noise ratios are employed in the parametric analysis to represent the measurement errors in the MFL tool. The results of the parametric analyses are then used to train and validate a convolutional neural network (CNN) model to predict the location, depth, length and width of the corrosion defect simultaneously. The results indicate that the developed CNN model has a high predictive accuracy.
Comparison of Impact Toughness Properties in Grade 22 Steel HAZ After PWHT and Temper Bead Welding
Authors: Jang Eun , Alexandrov Boian , McCracken Steven L. , Barborak Darren
Published: November 2023

Welding of thick low alloy steel components without elevated preheat imposes rapid cooling rates that may promote martensite formation in the coarse-grained heat affected zone (CGHAZ). Freshly formed martensite contains a distorted and supersaturated matrix with high dislocation densities. As a result, fracture and impact toughness properties of these regions are inherently low and post weld tempering procedures are typically required. Conventional postweld heat treatment (PWHT) involves extended isothermal holds at elevated temperature which allows for considerable softening of the martensitic structure but has been found to have less effect on improving impact toughness. In contrast, short-term tempering processes with rapid heating and cooling rates and short times at elevated temperature have been shown to greatly improve impact toughness through a shift in the kinetics of martensite tempering that produces high number densities of refined carbides. Temper bead welding (TBW) was developed for inservice repair of thick steel components where PWHT was impractical or not possible. With temper bead welding, the heat-affected-zone is tempered by one or more rapid re-heat cycles from overlapping weld beads or weld layers. This study compares the Charpy V-notch impact toughness and fracture morphology of the CGHAZ in the as-welded condition, with conventional PWHT, single temper bead reheat, and multiple temper bead reheats for an SA-387 Grade 22 alloy steel.
Fatigue Crack Growth Rate Study of New X52 Line Pipe Steel in Hydrogen Blended Methane
Authors: Chandra Ashwini , Thodla Ramgopal , Sosa Siari
Published: November 2023

Hydrogen is an alternative fuel to consider for decarbonization as its combustion does not result in production of greenhouse gases. The transport of hydrogen from production to end use location is a critical part of deployment and blending of hydrogen in the natural gas transmission and distribution pipeline network is a cost effective option. However, the interaction of hydrogen with the pipeline material needs to be evaluated due to risks associated with hydrogen embrittlement. In this study, fatigue properties of a new X52 line pipe material with an HFW seam weld was evaluated to identify the impact of up to 10% hydrogen blending at a pressure of 1800 psi. A fracture mechanics-based approach was used to test the fatigue crack growth rate (FCGR) of microstructures associated with parent pipe, seam weld, seam weld – heat affected zone (HAZ), girth weld and girth weld HAZ. The gas environment was simulated in an autoclave pressurized to 1800 psi (12.4 MPa) total pressure using 1, 5 and 10 mole% hydrogen blends in methane. FCGR was also measured in 100% methane environment to establish a baseline to compare the properties in the selected hydrogen blends. The Paris curves were measured at a constant R ratio of 0.3. Increase of the FCGR above those measured in the 100% methane environment baseline was observed for all the microstructures at all concentrations of hydrogen. The degree of increase in FCGR as well as in the range of stress intensity factor (ΔK) where the increase was observed, varied to some extent between microstructures. Results were also compared to the ASME B31.12 curve for carbon steel in hydrogen, to understand the degree of conservatism associated with the ASME curve for the hydrogen blends.
Modeling and Experimental Analysis of Electromagnetic Ultrasonic Testing Considering Effect of Rough Surface
Authors: Wang Zhe , Fan Zhichao , Chen Xuedong , Cheng Jingwei , Wang Haibin , Bu Yangguang
Published: November 2023

Electromagnetic acoustic transducer (EMAT) is widely used in wall thickness measurement, which is suitably used in periodic inspection or long-term monitoring of pressure equipment. However, the corroded surfaces appearing on the pressure pipes and vessels usually cause an increase of background noise and variation of sound field, which restrict the improvement of measurement accuracy. In this paper, a numerical model of EMAT containing random rough surface is established based on the constitutive equation of Lorentz force and magnetostriction force. The distribution of eddy current at the skin layer in the excitation or receiving process of EMAT are analyzed. The characteristics of energy conversion of multi-physical coupling fields under effect of rough surface is clarified. Then, the variation law of measurement accuracy of wall thickness for EMAT under rough surface is obtained and compared by simulation and experiment. The results show that more interference sound waves come into being under rough front surface and the attenuation of signal-to-noise ratio (SNR) is more significant comparing to rough back surface. When the roughness is within 120μm, a better wall thickness accuracy can be obtained by means of multiple measurements. When the surface roughness is larger than 120μm, the measurement error exceeds 0.1mm. Therefore, when the surface of pressure equipment is in good condition, the high-precision thickness measurement of EMAT without grinding process can be realized. Otherwise, local grinding can significantly improve the measurement accuracy.
Fracture Toughness Estimation of High-Grade Pipeline Steel Girth Weld in Ductile-Brittle Transition Zone
Authors: Gui Lele , Zhou Tianyu , He Renyang
Published: November 2023

Determination of fracture toughness for weld has always been a difficult problem because of the existence of defects and material discontinuity in weld. In this paper, the fracture toughness distribution and ductile-brittle transition characteristic of X70 pipeline steel girth weld were investigated by means of fracture toughness curves based on RTNDT, master curve method, instrument indentation method and convention fracture toughness test, applicability of these methods is studied by comparing with actual-measured fracture toughness values and charpy impact test results. The results show that fracture toughness curves based on RTNDT are sufficiently conservative in the whole ductile-brittle transition zone and lower bound. The lower envelop curve is more conservative when it is higher than DBTT, while revised fracture toughness curve is more conservative when it is lower than DBTT. The reference temperature of Master Curve for X70 pipeline steel girth weld by 0.5T SE(B) specimens equals −98 °C, 1% and 95% cumulative failure probability curves can well envelop the fracture toughness distribution of X70 girth weld, which shows great flexibility in the estimation of fracture toughness of X70 pipeline steel girth weld. Fracture toughness values of ductile mode by instrumented indentation can be used to estimate the DBTT of X70 girth weld.
Application of Multivariate Acoustic Emission Parameters in Damage Monitoring and Assessment of a Low-Alloyed Steel
Authors: Lai Chuanjing , Xu Wei , Chai Mengyu , Duan Quan , Zhang Zaoxiao
Published: November 2023

Acoustic Emission (AE) as a nondestructive evaluation technique has been frequently utilized to monitor the damage progression of materials and structures. Analysis based on multivariate features is more viable in completely understanding the damage progression than using only one single or limited AE parameters. Program or software facilitates the processing of AE data by finishing the feature extraction and other analysis work. This article presents the application of multivariate AE parameters in damage analysis and evaluation of a low-alloyed steel. An AE software system to understand the AE events multi-dimensionally is developed. The software is capable of feature extraction, visualization, variational mode decomposition (VMD) and Hilbert-Huang transform (HHT) for the source mechanism analysis. The AE signals generated from three-point bending of Cr-Mo steel was processed and analyzed to verify the viability of the system. Nineteen different AE features are calculated from time and frequency domains. The variation of different features associated with AE events among different stages of the test are discussed. Moreover, AE signals are decomposed by VMD into several modes that indicate the dominant frequency of AE events. Hilbert spectrum obtained via HHT presents the amplitude of AE signal in both time and frequency domain. The results of the application may provide insights in multivariate feature extraction and methods of damage assessment in metallic materials and engineering structures.
Design of Centrifugally Cast Fe-Cr-Ni Heat-Resistant Alloys Driven by Material Genome Technology
Authors: Fan Zhichao , Xiang Shulin , Chen Tao
Published: November 2023

Due to the excellent creep and corrosion resistance at high temperatures, heat-resistant alloy tube is the key component of hydrogenation reformer and ethylene pyrolysis furnaces in petrochemical industries. The development of material genome technology provides a new idea for the control and optimization of heat-resistant alloys. Based on the CALculation of PHAse Diagram (CALPHAD) method, the effect of key microalloying elements on the evolution of phases is detected, hence the preliminary content range of the microalloying element is determined. According to coupled finite element-cellular automaton (CAFE) model and experimental verification, the grain morphology model of centrifugal cast heat-resistant alloy is established, and the optimized parameters of pouring temperature and rotation speed are put forward. The correlation analysis between component/microstructure and creep rupture life is carried out using a machine learning (ML) approach. The classification of alloy microstructure (grain size, primary carbide morphology, etc.) based on a convolution neural network is established, and the regression of creep rupture life using a deep learning model based on multi-source heterogeneous data is exploited. Combined with the optimization algorithm, an accurate design of alloy composition for target service life is developed. The alloy design method based on material genome technology will accelerate the R&D and application of new heat-resistant materials and advanced components.
Investigation of Ultimate Behavior of Elbow Pipes by Tensile Loading Test in the Direction of In-Plane Bending
Authors: Shimazu Ryuya , Sakai Michiya , Ono Yohei
Published: November 2023

Probabilistic risk assessment is useful in considering the safety of nuclear power plants. To recognize the weaknesses of structures, a realistic fragility assessment must be conducted. Furthermore, it is important to set the failure mode appropriately for a realistic fragility assessment. However, few experimental data for the ultimate state of elbow piping with ductile rupture compared to fatigue exist. In this study, tensile loading tests of full-scale elbow pipes were conducted to enrich the knowledge of failure modes of piping systems. 150A Sch80 and 200A Sch40 elbow pipes made of carbon steel (JIS STPT410S) did not rupture despite the ductility factor exceeding 30. Therefore, the possibility of ductile rupture of elbow pipe under earthquakes is extremely low. Aiming at a realistic fragility assessment of ductile rupture, analytical models that precisely predict the test results were investigated. For a 150A Sch80 pipe, which did not show buckling deformation in the test, the FEM model using shell elements was able to predict with good accuracy. For a 200A Sch40 pipe, even one that buckled at the top of the elbow, the behavior, including buckling, was able to be predicted with good accuracy.
Exploring 3D X-Ray Diffraction Method to Validate Approaches in Materials Modelling
Authors: Ramadhan Ranggi S. , Al Mamun Abdullah , Ball James A. D. , Demir Eralp , Collins David M. , Agius Dylan , Mostavafi Mahmoud , Knowles David
Published: November 2023

Cyclic high temperature deformation, which is a precursor to creep-fatigue damage is one of the main life limiting factors in thermal power plants. Microstructurally informed models such as crystal plasticity have shown great promise in predicting cyclic plasticity and creep deformation; however, further validation of predicted meso-scale deformation is required to ensure accurate damage calculations. Here, a novel 3D X-ray diffraction (3DXRD) experiment was performed to resolve and investigate the response of individual grains within a polycrystalline material under loading at elevated temperature. Specimens were made from 316H stainless steel, which is an alloy commonly used for critical structural components in thermal power generation plants. The 3DXRD experiments were conducted at the UK national synchrotron facility, Diamond Light Source. The measurements provided positions, strain tensors, and orientations of individual grains within a gauge volume. The data generated from 3DXRD was used both as an input and for the validation of a crystal plasticity finite element model (CPFE). The results provided demonstrate the importance of microstructural information in materials modelling.
Overview of Revisions to the ASME Boiler and Pressure Vessel Code Section VIII Division 3 for the 2023 Edition and Near Future
Authors: Peters Daniel T. , Subramanian Kannan , Sarzynski Melanie
Published: November 2023

This paper gives an overview of the major revisions pending in the upcoming 2023 edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section VIII Division 3, Alternative Rules for Construction of High Pressure Vessels, and potential changes being considered by the Subgroup on High Pressure Vessels (SG-HPV) for future editions.

This will include an overview of significant actions which will be included in the upcoming edition, including updates to the rules for User’s Design Specifications (UDS’s). Many changes include clarifications regarding subjects such as the definition of T vs. t in material testing, and the supplementary requirements for toughness testing in KM-250 and when they are required. Another was to clarify that the requirements in ASME VIII-3 which may conflict with certain requirements in material specifications make it such that all parts of material specifications do not need to be followed. There was another change regarding interpolation between low alloy fatigue curves. Another significant change was clarification regarding which constitutive material model is to be used in various design by analysis situations and the need for consistency between those material models. Several changes were also made regarding environmental interaction and stress corrosion cracking.
Investigation on a Method of Counting Low-Cycle Fatigue in Steel Under Crack Closure and Random Variable Amplitude Loading
Authors: Watanuki Jo , Kawabata Tomoya , Takagi Shunsuke
Published: November 2023

Low-cycle fatigue (LCF) plays an important role in the evaluation of steel structures subjected to cyclic large stresses, such as the reactor pressure vessel. In LCF, fracture is caused by the propagation of cracks generated by large deformations. Therefore, it is important to predict how the cracks will grow and when the structures are broken. However, the conventional method for predicting the number of cycles of fracture (Nf) in LCF is incomplete. This is because it is not revealed whether the conventional counting method of the number of random amplitudes, Rain Flow Method, can be applied after crack initiated because the crack closure occurs. This means that the invalid cycles which do not contribute to the crack propagation due to the crack closure are counted by using Rain Flow Method. In other words, it is required to confirm whether Rain Flow Method is applicable to the cracked material and make a mechanism for precisely predicting the life in random LCF amplitudes by removing the crack closure.

In this paper, the validation of Rain Flow Method was investigated with following two steps. First, the relationship of the ΔVg, amp-Nf were obtained. Second, the prediction of the life in random LCF amplitudes was employed through ΔVg, amp-Nf, Rain Flow Method and Linear Cumulative Damage Rule (LCDR). In addition, the investigation of how to remove the crack closure was conducted by using the point of the change of slope of P-Vg, the analysis of dadN-Δδeff, and FE model.