bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of High Temperature Creep Strength of Conventional Grade 91 Steel by Thermomechanical Treatments
Authors: Hernández Rebeca , Serrano Marta , García-Junceda Andrea , Oñorbe Elvira , Vivas Javier 
Published: November 2019

Abstract
The study of the enhanced creep strength of conventional ferritic-martensitic (F/M) grade 91 steel by a thermomechanical treatment (TMT) to increase the precipitation of MX particles in the matrix was performed.
Creep properties were evaluated by tests at constant load at temperatures that varied from 600 °C to 700 °C with different levels of stress for both steels: T91 and T91-TMT. The creep curves and main parameters for both steels in the different conditions were analysed.
Results show a great improvement of creep strength of the T91 after the thermomechanical treatment in comparison with the conventional steel. T91-TMT presents a rupture life significantly higher than T91 and a decrease of the values of the minimum creep rate.
An increase of the density of MX precipitates in the matrix of the T91-TMT due to the thermomechanical treatment in comparison with T91 can be also observed.
A change in the fractography was also detected. T91-TMT specimens showed signs of brittle fracture instead of the ductile fracture, with the common necking effect detected in the T91.
Flaw Acceptance Evaluation for the Final Disposal Canister Under Earthquake Induced Rock Shear
Authors: Chou Hsoung-Wei , Wu Szu-Ying 
Published: November 2019

Abstract
When a canister used for final disposal of spent nuclear fuel is in the deposition hole of deep geological repository, the loading case which would most impact the structure integrity of the canister is to postulate an earthquake induced rock shear through a deposition hole. This paper evaluates the acceptable sizes of defects in the cast iron insert of canister using fracture mechanics analysis. The submodelling technique of finite element analysis was employed to calculate the fracture behavior of the canister with postulated defects subjected to shear loads due to earthquake. At first, the stresses of the global model and the uncracked submodel were compared to check the correctness of the transferred displacements from the global model to the submodel. Then, surface and internal flaws with various shapes and depths were modeled individually in the submodel. A 5 cm shear displacement was applied on buffer and then transmitted to the canister. The calculations of J-integral of each flaw indicate that the surface semi-elliptical defect is more critical and the density of buffer material significantly affects the acceptable size of postulated defects. Present results can provide acceptance criteria of crack detection for canisters during manufacture and examination processes.
Study of the Flow Field in Cylindrical Vessel
Authors: Yang Sha , Dong Qi , Zhang Liucheng , Feng Jiahe , Hu Rongxi 
Published: November 2019

Abstract
A tooth-lock cover is a kind of convenient closure used in explosive containment vessels. But in experiments, it is found that a small amount of explosive exploded in cylindrical vessels could cause severe deformation to the tooth-lock covers. In some situations, the cover would even be blown out of the vessel with severe distortion. The spreading and superposition of the shock waves in the cylindrical vessel is studied in this paper. Impulse is chosen as the evaluation parameter instead of the peak pressure because of the reflection and superposition of the shock waves. The piston method is used to calculate the impulse and the result is verified in 8-tooth cover vessels. This method can evaluate the intensity of the shock wave loaded on the cover. It would be useful in the optimization of the explosion containment vessels.
High Performance Structural Vibration Control by a Preview of the Future Seismic Waveform Generated With a Wave Transmission Network and an AI-Based Estimation System
Authors: Hiramoto Kazuhiko , Matsuoka Taichi , Sunakoda Katsuaki 
Published: November 2019

Abstract
We propose a new active vibration control strategy based on the future seismic waveform information obtained in remote observation sites. The waveform information in the remote site is transmitted by a waveform transmission network to the structure under control. The waveform transmission network is realized by interconnecting multiple controlled structures and observation sites. By using the future waveform information obtained through the network, we propose a control law realizing fairly higher control performance over the conventional structural control methodologies. A preview control law consisting of the state-feedback and feedforward control (preview action) is adopted. For the preview action, future values of the disturbance in some time interval are necessary. However, because the future value of the earthquake waveform is unknown, the preview action contributing the performance improvement is generally impossible. To get over this difficulty, an AI-based wave estimation system to estimate the future earthquake waveform is proposed. The wave estimation system is a multi-layered artificial neural network (ANN). Through a small scale simulation study with a recorded earthquake event in Japan, we show that the proposed control method achieves much higher control performance over the conventional LQ-based active control.
Effective Shank Length of Bolts Under Lateral Loading
Authors: Gao Yong-Jian , Chen Bing-Bing , Zhang Zhai , Zheng San-Long , Yu Qing , Xie Cheng-Chen 
Published: November 2019

Abstract
Additional lateral load tests, with improved techniques, were conducted on M22 stainless bolts to supplement the series of metric system stainless bolt tests which were conducted previously. Using the strain gage-deflection data collected from the entire set, i.e., of different sizes and different lengths, of the bolt tests, the “rigidity coefficient”, which is used in calculating the deflection of the bolts under lateral loads, using the conventionally assumed effective shank length, is derived.
Alternatively, a new analytical effective shank length, which is more accurate than the conventional assumed effective shank length, derived from the test data, is proposed.
Fatigue Analysis for the Lower Assembly of a U-Tube Steam Generator
Authors: Cao Moli J. 
Published: November 2019

Abstract
The lower assembly of a U-tube steam generator consists of a hemispherical primary channel head with a flat bottom, a perforated tubesheet, a partition plate, and a portion of lower shell. The partition plate divides the primary channel head into two halves. Each half contains a primary nozzle and a manway opening. The fatigue analysis of the lower assembly of a U-tube steam generator can be a challenge due to the complexities of the geometry and loading conditions. In this paper, the development of a global finite element model including all important features and several submodels to cover the effects of all these features is described. The tubesheet is simulated using equivalent solid properties with orthotropic material properties. The thermal loads from the inner surfaces of the tubes embedded in the tubesheet are implemented using surface elements. The submodeling technique is utilized to evaluate the local small features, such as tube holes at primary and secondary faces of the tubesheet, with the constraints at the cut-boundaries and the temperature fields of the submodel being extracted from the global model.
On Modeling and Assessment of Bulk Liquid Storage Tanks With Foundation Settlements
Authors: Zhao Mingxin 
Published: November 2019

Abstract
A comprehensive study is conducted on finite element modeling and stress analysis techniques of above ground atmospheric bulk liquid storage tanks with foundation settlements. Both 2-D and 3-D modeling are examined for their applicability and limitations. Simple elastic analysis and 3-step method using a hybrid elastic-plastic procedure are explored and compared. In addition, data processing techniques are proposed to extract effective settlements from tank inspection measurements, which could be used for proper reconstruction of a settled foundation in finite element model. Procedures and practices are proposed and demonstrated to improve the finite element modeling and analysis of storage tanks.
Industry Experience Fabricating Hydroprocessing Reactors Using 2¼ Cr-1 Mo-V Steel
Authors: Shargay Cathleen , Antalffy Leslie , Daru Kuntak 
Published: November 2019

Abstract
Starting in the 1980’s, the process conditions for hydroprocessing reactors became increasingly more severe and started to exceed the economic and technically-feasible ranges for 2¼Cr-1Mo steel. Hence, new grades of reactor steels were developed to meet these demands. Reactor fabricators, steel producers, the Materials Properties Council and some refiners cautiously developed their initial applications of the new materials, with extensive testing of both the materials and fabrication methods, and restrictions to use only the most experienced, highly technical fabrication shops. The data and experience has grown exponentially since then and today, the most commonly-specified material for thick wall reactors is 2¼Cr-1Mo-¼V steel.
The list of qualified fabricators worldwide has also grown, but is still limited. The purpose of this paper is to show how the industry has climbed the “learning curve,” by giving the statistics on the overall numbers of fabricated reactors (which is now over 1150), and the locations of the fabricators by country, that have been produced. Trends on the use of forgings versus plates are also included, along with the major changes over the years in the applicable ASME Codes and API standards affecting these reactors. Some of the lessons learned from past fabrication problems are also discussed along with the subsequent safeguards initiated within the industry standards.
Effect of Pre-Strain and Aging Heat Treatment on the Corrosion Behavior for 2205 Duplex Stainless Steel in 6% FeCl3 Solution
Authors: Zheng Chengsi , Fei Qingnan , Kong Weihai , Ai Zhibin 
Published: November 2019

Abstract
A 2205 duplex stainless steel (DSS) was pre-stretched to 5% and subsequently aged at 850 °C for 0–120 minutes, to explore the effects of pre-strain and aging treatment on the corrosion behavior of the DSS in 6% FeCl3 solution at 50 °C for 72 hours. The microstructure, hardness and corrosion behavior of the pre-strained and aged DSS were investigated based on statistical data and physical metallurgy in comparison with the counterparts without pre-strain. The results showed that the sigma (σ) phase precipitated firstly in δ-ferrite grain boundaries and then in δ-ferrite/γ-austenite (δ/γ) phases boundaries by consuming the volume fraction of δ-ferrite. The volume fraction of σ phase in the DSS with and without pre-strain increased with increasing aging times following a classical Johnson-Mehl-Avrami (JMA) relationship, and the kinetics of the precipitation of σ phase was accelerated by pre-strain throughout the aging time of 60–120 min. The hardness of the non-pre-strained DSS (NP-DSS) was lower than that of pre-strained DSS (P-DSS) throughout 0–120 min at 850 °C. The hardness of NP-DSS increased continuously with increasing aging time, and the hardness of P-DSS decreased firstly and then increased continuously with increasing aging time. The aged NP-DSS displayed a gradually serious pitting with increasing aging time, and the corresponding corrosion behavior of the aged P-DSS exhibited pitting firstly and then mainly cracking, and the pitting occurred in the vicinity of δ/σ and γ/σ boundaries.
Research on the Interference Fit of GV Seat Under the Service Load
Authors: Hu Yifeng , Xu Sihua , Chen Gang 
Published: November 2019

Abstract
The governor valve is a very important component in steam turbine, which can change the power output of the steam turbine by controlling the amount of the inlet steam. The service conditions of governor valve is very complicated, which should suffer high temperatures, high pressure, erosion, water induction and so on. As we all know the fatigue and creep can significantly reduce valve life. However, the damage due to governor valve seat interference fits is also very important for the units’ safety operation. A compromised interference fit can lead to significant valve leakage and possibly catastrophic seat failure. This article bases on a real case from a STP’s SC unit, which is operating in the South Asia market. Simulating the behavior of the valve seat under service conditions by numerical method, to find out the root cause of the interference fit failure and the operational advice for the unit running.
Analysis Approach Examples for Flow-Induced Piping Vibration Mitigation
Authors: Voll Brian J. 
Published: November 2019

Abstract
One of the challenges of analyzing flow-induced vibration in piping systems is determining how to analytically characterize the loading related to the source of the vibration. Simplified methods can be sufficient for evaluating an existing piping configuration through correlation with vibration measurements. However, if vibration mitigation is required a more thoughtful analysis approach should be used so that the anticipated vibration responses of the post-modification piping configuration can be more accurately determined.
Two case histories are presented that illustrate analysis approaches used to evaluate the severity of flow-induced piping vibration and also develop effective vibration mitigation designs. The analysis approaches used in both cases involved the simulation of vibration loading based on limited vibration data. Using the analysis approaches that were developed, vibration restraints were able to be effectively located and designed. The effectiveness of the analytically determined vibration mitigation solutions was confirmed by post-modification testing and observation.
Preparation and Properties of Au/SnO2 Thermocouples for Material Testing Apparatus of Pressure Equipment
Authors: Liu Xiaoliang , Chen Xuedong , Fan Zhichao , Jiang Huifeng 
Published: November 2019

Abstract
Thermocouples are the most common temperature measuring components in petrochemical, metallurgical, aerospace and other fields. However, due to the influence of working environment and its own structural characteristics, the thermocouple is highly susceptible to electromagnetic interference in the environment during its work, which seriously affects its temperature measurement accuracy. In this paper, three different shapes of Au/SnO2 thermocouples were prepared by screen printing technology, and their microstructure, thermoelectric properties and anti-electromagnetic interference were studied. The results show that the Au/SnO2 thermocouples with different shapes can crystallize well after sintering at 750 °C and above. When temperature difference is from 50 to 300 °C, thermocouples with different shapes can produce stable thermoelectric potential, and the shape has no effect on the output thermoelectric potential. The Au/SnO2 thermocouple after 850 °C sintering has the best thermoelectric performance. Au/SnO2 thermocouples can work normally in electromagnetic fields of 3 V/m or less, while standard PtRh10-Pt thermocouples can not work normally in electromagnetic field of 3 V/m. The Au/SnO2 thermocouple obtained in this study has the advantages of simple preparation method, small size, stable output thermoelectric potential and strong anti-electromagnetic interference ability.
Evaluation of Welding Techniques for Stainless Steels Piping Without Use of Backing Gas
Authors: Chiluvuri Siva Kumar , Bliss Kevin , Penso Jorge 
Published: November 2019

Abstract
In the piping fabrication industry Gas Tungsten Arc Welding (GTAW) is used extensively for welding of stainless and high alloy steel pipes, mainly for root pass of single side joints. GTAW process uses an inert gas for both shielding and backing of the weld. Backing gas also known as purge gas, is provided mainly to prevent oxidation of root pass weld from inside the pipe. Typically, Argon or Argon mixture (i.e. Argon with Helium, etc.) are used as backing gas. Argon gas, is colorless, odorless and heavier than air. Many safety incidents have occurred in the Oil and Gas industry (mainly during construction phase) due to asphyxiation. This has typically occurred when a person (usually a welder) goes inside the piping (a confined space) to inspect the root pass weld to ensure it will pass radiography test. Construction industry has failed to fully tackle this issue in a meaningful way and as a result, some significant number of fatalities occur each year. On several occasions, such incidents have resulted in multiple fatalities when coworkers enter the confined space to rescue and become a victim by themselves.
There are a multitude of reasons why people put themselves at risk in this way. Reasons given for a reluctance to use alternative techniques that eliminates backing gas are many and varied. Alternate welding techniques without backing gas were developed many years ago. However, they are still not being used extensively for many reasons and apprehensions. Using these alternate welding techniques with right controls in place, can eliminate the hazard associated with backing gas and improve safety and maintain quality. This paper discusses and evaluates the alternate welding techniques (which do not require backing gas), limitations, welding procedure qualification and inspection requirements.
Probabilistic Fracture Mechanics Analyses Comparison to LBB Assessments
Authors: Kurth Robert , Sallaberry Cedric , Kurth Elizabeth , Brust Frederick 
Published: November 2019

Abstract
Analysis of a generic dissimilar metal weld (DMW) susceptible to primary water stress corrosion cracking (PWSCC) in a pressurized water reactor (PWR) is used to compare the newly developed probabilistic models (xLPR code) to the previously performed deterministic leak before break (LBB) analyses. The objective of this scoping analysis is to develop a generic reactor loop composed of representative welds and to investigate the safety margins in the presence of PWSCC at the Alloy 82/182 locations. These locations have been previously studied and approved for LBB, however not in the presence of active degradation such as PWSCC. The purpose of this study is to investigate potential increase in risk due to this mechanism. Comparisons of the individual weld probabilistic results to the deterministic LBB analysis are made as the first results of this study. Additionally the individual welds are combined into a configuration representative of the primary loop. This configuration is then tested against the criterion recommended by the xLPR acceptance group. This xLPR criterion is then compared to the existing LBB criterion to assess the change, if any, in risk due to PWSCC.
Three-Dimensional Liquid Sloshing Numerical Analysis on a New Designed Tank Container
Authors: Yue Wenjun , Chen Xu 
Published: November 2019

Abstract
Based on the conventional tank container which has a cylindrical vessel, a new structure of tank container was designed to improve the carrying capacity of the tank. Fluid flow inside the new tank container under different operating conditions (liquid filling ratio K, braking deceleration a, filling medium, no baffle and with baffles) was studied. A volume-of-fluid (VOF) method and a k-epsilon (k-ε) turbulence model were used to simulate the fluid flow. Results showed that all the factors studied in this work had an influence on the tank. The maximum impact force increased with the increasing of a and K. A clear linear positive correlation was found between the maximum impact force and braking deceleration. Besides, the maximum impact force had a relationship with the density of medium. Compared with the conventional tank container, the carrying capacity of the new type tank container increases by 11.8%, which means the new type tank container has better economic benefits.
Leak Behavior and Prediction of Metal Ring Joint Gaskets in Simplified Leak Test With Grooved Platen
Authors: Omiya Yuya , Fujii Masahiro 
Published: November 2019

Abstract
Pipe flange connection with metal gasket is used under high temperature and pressure in place required high sealing performance. It has been known that gasket compressive force, which is closely related the leakage decreases by internal pressure action. Since the pressure is very high in metal gaskets, the sealing performance evaluation in internal pressure action is important. However, there is little research that evaluates a little leakage, metal gasket is empirically used up to the present time. Therefore, evaluated sealing performance of metal gasket, it is necessary to clarify the sealing mechanism. In this study, evaluated effect that decreasing of gasket compressive force affects leakage in both octagonal type and oval type in ring joint gasket by simplified leak test using grooved platen and finite element method stress analysis, evaluation method of leakage in metal gasket is proposed. Based on this evaluation method, decision method of initial tightening force that guaranteed one amount of leakage to design internal pressure is shown in pipe flange connection with metal gasket.
Effect of Tightening Procedure on the Sealing Performance of Bolted Gasketed Pipe Flange Connections
Authors: Zheng Xing , Sato Koji , Fujihara Takahiro , Akamatsu Yoshiko , Sawa Toshiyuki 
Published: November 2019

Abstract
The objective of the present paper is to examine the effect of tightening procedure on scatter in axial bolt forces and the bolt forces distribution in bolted gasketed pipe flange connections where spiral-wound gaskets and PTFE blended gaskets are used. The scatter in the axial bolt forces was examined by several tightening procedures which are JIS B 2251, ASME PCC-1 legacy, ASME alternative #1, #2, #3 and 3 rounds method procedures in ASME 24“ bolted gasketed pipe flanged connection. The leak rate of the tightened bolted flanged connections was also measured. Furthermore, the assembly efficiency based on both axial bolt forces and the tightness parameters of the bolted pipe flange connections was calculated and compared. The obtained results are as following. First, the leak rate of the connection tightened by JIS procedure is the lowest of all the tightening procedures. Second, the assembly efficiency based on axial bolt forces tightened by JIS procedure is the highest, and the assembly efficiency based on tightness parameters according to JIS procedure is also the highest. Third, the assembly efficiency based on tightness parameters is smaller than that based on the axial bolt forces. As a conclusion, the JIS B 2251 procedure is the most efficient tightening procedure of all the tightening procedures tested in the present study and the assembly efficiency based on the tightness parameters is suggested to design bolted connections for more safety.