bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probabilistic Creep Modeling of 304 Stainless Steel Using a Modified Wilshire Creep-Damage Model
Authors: Hossain Md. Abir , Cano Jaime A. , Stewart Calvin M. 
Published: October 2020

Abstract
Pressure vessel components subject to high temperature and pressure are susceptible to life-limiting creep and/or creep-induced failure. Traditional continuum damage mechanics (CDM) based creep-damage model are used extensively for the prediction and design against creep in these components. Conventional creep experiments show considerable uncertainty in the creep response of materials where scatter can span decades of creep life. The objective of this paper is to introduce the probabilistic methods into a deterministic creep-damage model in order to predict experimental uncertainty. In this study, a modified Wilshire model capable of creep deformation, damage, and rupture prediction is selected. Creep deformation data for 304 stainless steel is collected from the literature consisting of quintuplicate (five) tests at 600°C with varying stress levels. It is hypothesized that the scatter in creep data is due to: test condition (temperature fluctuations and eccentric loading), initial damage (pre-existing surface and sub-surface defects), and metallurgical (local variation in microstructure) uncertainties. Probability distribution functions (pdfs) and Monte Carlo simulations are applied to introduce the uncertainties into the modified Wilshire equations. The domain of each source of uncertainty must be defined. A systematic calibration approach is followed where the material constant for each creep curve (in the quintuple) are obtained and statistical analysis is performed on the material properties to assess the random distribution associated with each uncertain material parameter. The probabilistic calibration begins with the introduction of test condition randomness (±2°C and ±3.2% MPa of nominal temperature/stress) in accordance with the ASTM standards. Cross calibration of temperature-stress variability proceeds the approximation of initial damage uncertainty which captures the remaining scatter in the data. Deterministic calibration unveils the range of variabilities associated with the material properties. The best-fitted pdfs are assigned to each uncertain parameter and subsequently, the deterministic model is converted into a probabilistic model where reliability is a tunable factor. A large number of Monte Carlo simulation are conducted to generate probabilistic creep deformation, minimum-creep-strain-rate (MCSR), and stress-rupture (SR) predictions. It is demonstrated that the probabilistic model produces quantitatively and qualitatively good fits when compared with experimental data. Future work will be directed towards the inclusion of service condition related uncertainty (power plant, turbine blade, Gen IV nuclear reactor application) into the probabilistic framework where the uncertainties are more robust.
Creep Deformation Property and Creep Life Evaluation of Super304H
Authors: Kimura Kazuhiro , Sawada Kota 
Published: October 2020

Abstract
Creep deformation behavior, creep strength property and microstructural evolution during creep exposure were investigated on Super 304H steel for boiler tube. In the high stress and lower temperature regime, creep rupture strength of Super 304H steel is higher than that of SUS304H steel. The slope of stress vs. time to rupture curve of Super 304H steel, however, becomes steeper with increases in creep exposure time and temperature, and the creep rupture strength of Super 304H steel becomes closer to that of SUS304H steel after the tens of thousands of hours at 700°C (1292°F) and above. In the short-term, at 600°C (1112°F), creep rupture ductility increases with increase in creep rupture life. However, it tends to decrease after showing this maximum value and the creep rupture ductility decreases with increase in temperature. The complex shape of creep rate vs. time curves, with two minima in creep rate, was observed at 600°C (1112°F). Several type precipitates of niobium carbonitride (Nb(C,N)), Z phase (NbCrN), and copper were observed in Super 304H steel, as well as M23C6 carbide and sigma phase observed in SUS304H steel. The change in slope of stress vs. time to rupture curve is caused by disappearance of precipitation strengthening effect during creep exposure. Accuracy of creep rupture life evaluation was improved by stress range splitting method which takes into account the change in slope of stress vs. time to rupture curves was demonstrated.
Investigation of Failure Behavior of Polyethylene Pipe Reinforced by Winding Steel Wires Subject to Inner Pressure and Bending
Authors: Shi Jun , Miao Yuzhuo , Li Xiang , Li Guangzhong , Wan Yu , Lu Panling 
Published: October 2020

Abstract
Polyethylene pipes reinforced by winding steel wires (PSP) have been widely used in many fields such as chemical engineering, pulp conveying, water supply, etc. The combined loads of inner pressure and bending sometimes leads to the failure of PSP, and for engineering projects it is still not proposed that the failure criterion of PSP subject to combined loads. In this paper, full-size finite element models (FEM) of PSP under inner pressure and bending were established to investigate the engineering failure criterion. In the FEM the steel wires and HDPE matrix were modeled separately. The freedom degrees of steel wires and HDPE were coupled together as the interface between these two constituents were considered intact. The investigation contains two parts: firstly, a FEM was established in reference to the details of an existing experiment, including the pipe specimen and relative boundary condition. The validation of the FEM was carried out and the simulation result agreed well with test result indeed. Subsequently, the model was optimized to undertake four-point bending under inner pressure, to analyze the failure behavior of PSP under this kind of condition, with three factors such as varied ratio of diameters to thickness, inner pressure and volume ratio of steel wires. In the end, the curvature of failed PSP was considered as the failure criterion, and the relationship of curvature and the three factors were discussed. This paper is useful for the safety of PSP subject to inner pressure and bending load.
Low Impact Test Results in Carbon Steel Flanges, Fittings and Piping: End User’s View
Authors: Dalal Mitul , Penso Jorge 
Published: October 2020

Abstract
Carbon steel components (Flanges, Fittings and Piping) have been reported with low impact test results. Some have failed during hydrotest and start-up as well as in-service. Steel grades that have shown problems complying with impact test requirements are ASTM/ASME A105, ASTM/ASME A234 Gr. WPB and ASTM/ASME A106. ASTM A350 LF2. These components according to some design-fabrication industry standards are not suitable for use even though they complied with applicable ASTM/ASME materials standards meeting the mechanical properties and chemical composition. Some analyses have led to identify key contributing factors to this low impact test results including Chemistry/Micro-alloying, fabrication approach and use of 100% re-cycle steels. This paper presents summarize findings from numerous reports of failure, testing data and selected approach when screening these materials prior to installation. Based on literature review the need for improvement in the approach for mechanical testing including fracture toughness testing for modern materials was identified.
Investigation of Temperature Dependence of Weibull Parameters of the Beremin Model in Ductile-Brittle Transition Temperature Region
Authors: Hojo Kiminobu , Ogawa Naoki , Yoshimoto Kentaro , Hirota Takatoshi , Nagoshi Yasuto 
Published: October 2020

Abstract
The Beremin model can handle both the plastic constraint effect and data scatter for brittle fracture. Many researchers have been investigating its applicability for more than 30 years and are still discussing the temperature dependence of Weibull parameters used in this model. The authors have already presented the experimental and analytical investigation results for low alloy steel using C(T) specimens in several temperature conditions. The analysis suggested that the Weibull parameters are constant for temperature. In this paper fracture toughness tests of carbon steel using SE(B) specimens at −120°C and −50°C were performed and the Weibull parameters were determined by the test results at −120°C. KJc of the 5% lower bound and the 95% upper bound confidence limit at −50°C were predicted using the Weibull parameters from −120°C. As a result, the predicted 5% lower bound confidence limit was close to the lowest experimental KJc value, whose fracture mode was nearly cleavage fracture. This means there is no temperature dependency of the Weibull parameters and the results are similar to those of low alloy steel. On the other hand the predicted 95% upper bound confidence limit had a large gap when compared with the experimental upper KJc value. One of the reasons of large gap was estimated that the parameter fitting of the GTN model was performed without consideration of the parameters relating to the second void effect and a precise stress-strain field after a large ductile crack growth with several millimeters was not obtained.
Hydrodynamic and Structural Simulations and Measurements in an Explosively Loaded High-Pressure Vessel
Authors: Fehlmann Kevin , Spernjak Dusan , Cardon Devin , Hill Dallas , Yost Nathan , Llobet Anna 
Published: October 2020

Abstract
A containment and confinement pressure vessel system is under development to expand the capability to perform small explosively driven physics experiments at the Proton Radiography facility at Los Alamos National Laboratory (LANL). Two barriers of this vessel system are the Inner Pressure Confinement Vessel (IPCV) and the Outer Pressure Containment Vessel (OPCV).
To achieve high spatial resolution of proton images, radiographic windows (covers) of the Inner Vessel are located extremely close to the experiment containing high explosive (HE). While the Inner Vessel is designed to meet the ASME Boiler and Pressure Vessel Code, Section VIII, Division 3, Code Case 2564 criteria, the small separation between the explosive and the pressure-retaining boundary presents a unique requirement for designing dynamically loaded vessels. We present numerical simulations of HE detonation in the Inner Vessel for several HE configurations. Eularian hydrodynamic code is used to calculate pressure-time history on the inner vessel surface. The pressure-time loading is then imported into a Langrangian structural model, and high-fidelity structural dynamic simulations are performed to obtain stress and strain as functions of time. Simulations are compared against experimental measurements from dynamic testing. Dynamic experiments are conducted in a low-fidelity (LoFi) vessel prototype, to measure the pressure and strain in regions of interest in different vessel locations (body, radiographic windows, covers).
Coupling of Neutron Transport and Probabilistic Fracture Mechanics Codes for Analysis of Embrittled Reactor Pressure Vessels
Authors: Spencer Benjamin W. , Hoffman William M. , Collins Benjamin S. , Henderson Shane C. 
Published: October 2020

Abstract
In light water nuclear reactors, the reactor pressure vessel (RPV) plays the critical role of containing the reactor and coolant and is expected to maintain its integrity under a variety of conditions. The RPV is subjected to high neutron flux and temperature, which lead to material embrittlement and increase its susceptibility to fracture. The degree of embrittlement is highly dependent on the local fluence, so it is critical to accurately characterize the spatial distribution of fluence in the RPV when performing a probabilistic fracture mechanics (PFM) analysis, which individually evaluates the flaws introduced in the manufacturing process. Radiation transport codes typically focus on computing the neutron distribution within the nuclear reactor core to understand phenomena relevant to reactor physics. However, recent developments in the Virtual Environment for Reactor Applications (VERA) allow it to solve for a fuel-pin resolved in-core fission source and use Monte Carlo methods to compute neutron fluence accumulation at locations away from the core, such as within the RPV, with unprecedented accuracy. Grizzly, a PFM code, can read in a 3D map of the fluence computed by VERA, and directly use that in the PFM analysis. This represents a significant advance in the accuracy of the fluence used in PFM calculations. This paper provides an overview of this modeling approach demonstrates its application on PFM analyses of representative RPVs.
Evaluation of Hydrogen Gas Generation and Permeation in the 9979 Type AF Shipping Package
Authors: Flach Joshua P. , Blanton Paul S. , Hoang Don S. 
Published: October 2020

Abstract
The 9979 Type AF Shipping Package is a cost-effective radioactive material packaging designed by Savannah River National Laboratory (SRNL) that consists of two primary components: a foamed outer drum for structural protection and an inner containment drum. The packaging was designed to transport Highly Enriched Uranium (HEU), Low Enriched Uranium (LEU), and other isotopes not exceeding a Type A quantity. These contents have the potential to generate flammable hydrogen gas during transport due to the degradation of hydrogenous materials (e.g. water vapor, plastics, etc) by high-energy alpha radiation. Since 10 CFR 71.43(h) prohibits the incorporation of packaging features explicitly designed for continuous venting, alternative justification was required to demonstrate that the requirements of 10 CFR 71.43(d) for negligible reactions between packaging components and contents were satisfied. An analysis was performed to demonstrate that the potential for hydrogen gas generation over a one-year period was limited by the effects of permeation through the packaging materials. The rate of hydrogen collection was evaluated for both the inner containment drum and the outer structural drum under 10 CFR 71.71 Normal Conditions of Transport (NCT). The analysis concludes that the Lower Flammability Limit (LFL) for hydrogen gas will not be reached in a one-year shipping period assuming a minimum void volume is maintained within the drum.
Quantification of the Material Ductility Effect on Notch Fracture Toughness Using Numerical Damage Analysis Method
Authors: Park Eui-kyun , Youn Gyo-Geun , Kim Yun-Jae , Kamaya Masayuki 
Published: October 2020

Abstract
In this study, the finite element (FE) damage analysis based on the multi-axial fracture strain model was applied to investigate the effect of the material ductility on fracture resistance of notched defect. (The fracture toughness is used only for a cracked specimen and the fracture resistance is used for notched specimens throughout the paper.) To obtain the material property with different ductility, the tensile and fracture toughness tests of the cold-worked SUS316 were used. The damage model was determined from comparing the experimental data with simulated FE analysis results. Then the FE analysis was applied to calculate the fracture resistance according to the notch radius in each material. It shows that the slope of initiation resistance according to the notch radius was related to the material ductility. To quantify this effect of ductility, the relationship between notch fracture resistance and material tensile properties was confirmed.
Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 5 — Isolation Performance Applied to Reactor Building
Authors: Somaki Takahiro , Fukasawa Tsuyoshi , Okamura Shigeki , Miyagawa Takayuki , Uchita Masato , Yamamoto Tomohiko , Miyazaki Masashi , Fujita Satoshi 
Published: October 2020

Abstract
This paper presents the isolation performance of a three-dimensional base isolated Sodium-cooled Fast Reactor building. The three-dimensional isolation system consists of rubber bearing with the horizontal oil damper for the horizontal isolation system and disc spring units with vertical oil dampers for the vertical one, where the vertical one is set under the horizontal one to be arranged in series.
These elements excepting the horizontal oil damper have been developed for the three-dimensional isolation system through the static or the dynamic loading tests using a full scale or a half scale model. Regarding the horizontal oil damper which is necessary for the three-dimensional isolation system as well as the horizontal isolation system, the details would be described in Part 6.
The authors also have been tackled to create the analytical modeling for each element such as the disc spring units, vertical oil damper and rubber bearing. The previous studies from part 1 to part 4 clarified that the newly analytical model, each of which is defined by the differential equations, could accurately express relationships between the force and displacement of each element.
To demonstrate the reduction effect (performance) of the seismic responses for the three-dimensional isolation system, the seismic response analyses using newly analytical modeling were performed for the Sodium-cooled Fast Reactor building that is modeled into the multi-degree-of-freedom-system. The isolation performance of the three-dimensional isolation system is verified through the floor response spectra evaluated at the position where the primary components are placed, in comparison with those by the conventional 2D horizontally isolation system using the rubber bearing without the vertical elements.
Estimation of the Load Carrying Capacity of the Bellows Compensator for Gas Pipelines in the Areas of Mining Production
Authors: Stryzhalo Volodymyr , Zarazovskii Maksym , Bohdan Andrii , Yaskovets Zakhar , Antonchenko Vitalii 
Published: October 2020

Abstract
The stress state of pipelines in areas of mine production requires obligatory consideration the influence of ground displacements. In this case the rules for design pipelines include the additional actions, such as the wall thickness increasing or U-shaped compensators installation.
The Ukrainian coal mining industry requires the expanding of mine production areas. It leads to the situation where old pipelines, which are not designed for such loads, could rupture due to ground displacements. The principle of “extinguish a fire” is applied in this case. It consists in applying of stress reduction actions before certain stage of mine production (so-called lava), such as digging out long sections, cutting and sanding, which require the involvement of significant human and material resources. But, in some cases, even the large-scale application of these actions does not lead to the stress reduction to the acceptable level (especially for pipelines of diameter less then 200mm). So, to solve this problem the implementation of bellow compensators (BC) is proposed.
The present work consists of:
• experimental investigations of BC which are carried out in order to obtain its bearing capacity and to validate its designed parameters guaranteed by the manufacturer;
• simulation of the BC loading process using FEM with adjusting the way of contact modelling between the BC layers in such manner, to be best correlate with the results of experiments;
• the application of obtained results for modelling of stress state of real pipelines in the areas of coal mine production.
The results of experimental investigation of BC of DN100 is presented. Their include: hydrotest with axial displacements limitation; tension-compression cycles for different values of amplitude with simultaneously loading of the operating value of gas pipeline internal pressure; rupture pressure determination.
Based on the experimental results, numerical modelling and specified domestic software for stress state assessment in pipelines the optimal locations and the required number of BCs is determined for buried gas pipelines. The results of presented works allowed us not only to implement the BCs to gas pipelines DN100 in areas of mine productions, but also the necessary experience for creation of larger diameters BCs is obtained.
Study on Dynamic Pressure Effect of Gas Bearings in Fuel Cell Vehicles
Authors: Zhang Chenxin , Hong Weirong , Zheng Shuiying 
Published: October 2020

Abstract
The dynamic pressure effect can contribute to a better working performance of the gas bearing without changing its overall structure or increase its air supply pressure. To study the dynamic pressure effect of gas bearings, a new method of CFD numerical simulation with self-developed UDF dynamic mesh program was proposed. In this way, values of dynamic characteristics for gas bearings with different fluid fields and under different working conditions can be calculated. Based on the numerical simulation results, the influence law of rotational speed, gas film thickness, and radial eccentricity ratio on the dynamic characteristics (load-carrying capacity, stiffness and damping coefficients, static equilibrium position etc.) were obtained. Afterwards, a bearing’s performance test was conducted on a rotor-bearing system in the high-speed air compressor. Compared to the traditional methods, after the dynamic pressure effect was taken into account, the corresponding rotor dynamic calculation of critical speed is more in accordance with the experimental results, thus proved the credibility of the new CFD numerical simulation method with dynamic mesh.
Regression Analysis of Transition Temperature Shift Database for the Core Region Beltline Welds of WWER-1000 RPVs
Authors: Zarazovskii Maksym , Revka Volodymyr , Chyrko Liudmyla 
Published: October 2020

Abstract
The paper describes the history of application in Ukraine the methods of critical temperature of brittleness (CTB is WWER’s analogue of PWRs ductile to brittle transition temperature) prediction. Also, a current state of chemical factor consideration in radiation embrittlement of PWR and WWER regulatory documentation is briefly presented. It is shown that a chemical factor for WWER RPV have to be defined.
The present paper devoted to the identification of the radiation embrittlement chemical factor for welds only of RPV core region, since it is the most critical zone in terms of RPV resistance against fast fracture. For that, based on the results of WWER-1000 RPV surveillance program of all Ukrainian NPPs, the CTB shift database is created. And it is important to note that database of Ukrainian WWER-1000 reactors is the biggest among other WWER countries.
With using the statistical treatment of CTB shift Database the degree of influence of each chemical element (C, Cr, Cu, Mn, Mo, Ni, P, S and Si) on WWER-1000 RPV weld radiation embrittlement is obtained. It is also found that Silicon and Nickel (in decreasing order) have the greatest impact on the CTB shift. At that, influence of other element separately – is negligible from practical point of view. Nevertheless, due to the literature data (in the radiation material science field) about impact of manganese, additional statistical investigations are performed, which showed us that Nickel and Manganese have synergetic effect which almost the same as level of impact from Silicon element alone. Similar treatments, as with pairs Silicon-Nickel and Silicon-Manganese, as well as Silicon or Nickel with any other element combinations, showed as absence of any other synergetic effect.
Based on the statistical evaluation the general shape of CTB shift trend curve is proposed. Moreover, the recommendations related to the CTB shift trendline prediction are given, which, besides the chemical factor and shape of curve, include the way of considering the CTB shift data scatter.
The obtained results are expected to be the basis in the modern regulatory method for radiation embrittlement assessment of the Ukrainian WWER-1000 RPVs.