bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Relation Between Side Ratios of Rectangular Cross Sections and Secondary Vortices at Trailing Edge in Motion-Induced Vortex Excitation
Authors: Matsuda Kazutoshi , Kato Kusuo , Arise Kouki , Ishii Hajime 
Published: October 2017

According to the results of conventional wind tunnel tests on rectangular cross sections with side ratios of B/D = 2–8 (B: along-wind length (m), D: cross-wind length (m)), motion-induced vortex excitation was confirmed. The generation of motion-induced vortex excitation is considered to be caused by the unification of separated vortices from the leading edge and secondary vortices at the trailing edge [1]. Spring-supported test for B/D = 1.18 was conducted in a closed circuit wind tunnel (cross section: 1.8 m high×0.9 m wide) at Kyushu Institute of Technology. Vibrations were confirmed in the neighborhoods of reduced wind speeds Vr = V/fD = 2 and Vr = 8 (V: wind speed (m/s), f: natural frequency (Hz)). Because the reduced wind speed in motion-induced vortex excitation is calculated as Vr = 1.67×B/D = 1.67×1.18 = 2.0 [1], vibrations around Vr = 2 were considered to be motion-induced vortex excitation. According to the smoke flow visualization result for B/D = 1.18 which was carried out by the authors, no secondary vortices at the trailing edge were formed, although separated vortices from the leading edge were formed at the time of oscillation at the onset wind speed of motion-induced vortex excitation, where aerodynamic vibrations considered to be motion-induced vortex excitation were confirmed. It was suggested that motion-induced vortex excitation might possibly occur in the range of low wind speeds, even in the case of side ratios where secondary vortices at trailing edge were not confirmed.
In this study, smoke flow visualizations were performed for ratios of B/D = 0.5–2.0 in order to find out the relation between side ratios of rectangular cross sections and secondary vortices at trailing edge in motion-induced vortex excitation. The smoke flow visualizations around the model during oscillating condition were conducted in a small-sized wind tunnel at Kyushu Institute of Technology. Experimental Reynolds number was Re = VD/v = 1.6×103. For the forced-oscillating amplitude η, the non-dimensional double amplitudes were set as 2η/D = 0.02–0.15. Spring-supported tests were also carried out in order to obtain the response characteristics of the models.
Fracture Toughness Evaluation of Carbon Steels in Piping and Valve for Reactor Primary System
Authors: Uemoto Yoshio , Hirano Akihiko , Hirasawa Daisuke 
Published: October 2017

UK very high integrity (VHI) component classification includes design, manufacturing, and inspection requirements that go beyond those established in ASME BPVC Sec. III Subsection NB [1]. One of these requirements is to ensure the component is tolerant of manufacturing defects. This can be demonstrated using a Defect Tolerance Assessment (DTA) based on two parameters fracture mechanics method. The brittle fracture parameter of this assessment requires the analysis of stress occurring in the component against the plane strain fracture toughness, KIC of the material.
This work focuses on the practical determination of KIC for materials chosen for a Boiling Water Reactor (BWR) Main Steam Piping (MSP) and Main Steam Isolation Valve (MSIV), which carbon steel seamless pipe SA-106 Grade C and carbon steel casting SA-216 Grade WCB, are respectively. These materials are usually tested by Charpy impact testing specified in [1], but there are not many studies reporting their KIC, and there is not enough information concerning actual piping and valve materials. Thus the authors implemented fracture toughness testing using J-resistance curve according to ASTM E 1820 [2] for test pipe and test casting block simulating actual MS Piping and MSIV, and evaluated KIC(J) to be used in DTA. KIC(J) is evaluated from elastic-plastic fracture toughness, JIC, gained from the J-resistance curve, and equivalent to KIC [3]. KIC(J) corresponds to KJIc in ASTM E 1820.
There were some cases, however, in which valid JIC values could not obtained, because of the materials high toughness, test specimen size limitations, and uneven final crack sizes. When valid JIC can’t be obtained, retesting or remanufacturing would significantly affect plant construction schedule. Hence, alternative evaluation methods by which JIC can certainly be obtained are desired.
In this study, the authors focused on two types of alternative JIC evaluation methods. The first one is the Stretch Zone Width (SZW) method, in which JIC is calculated from SZW measurements of crack tip plastic blunting on fracture toughness test specimens. The SZW method was well studied in the 1970s, and experimental data showed a clear correlation between JIC values obtained from J-resistance curves and JIC values obtained from SZW measurements [4]. The second method is by correlation of JIC with the energy absorbed during Charpy testing. As represented by Rolf’s study [5], it has been reported that there are correlations between Charpy absorbed energy and KIC for high tensile strength steels. In this study, the validity of the SZW method was first evaluated by comparing its results with JIC obtained from J-resistance curves. Then, the applicability of the JIC values to DTA of actual products was discussed. Finally, by comparing Charpy absorbed energy and KIC(J), the validity and applicability of KIC determination method with Charpy absorbed energy was discussed.
Relative Influence of Offset Spacing and Transition Support Location on Buried Piping Seismic Stresses
Authors: Frazee Glenn R. , Marohl Michael P. H. , Musto Thomas M. 
Published: October 2017

The design of buried piping systems requires special considerations. In the evaluation of seismic loads on buried piping, the associated stresses are typically considered to be secondary stresses as the piping is assumed to move with the soil during a seismic event and inertial seismic loads are considered to be negligible. During a seismic event, buried pipes are subject to relative displacement-induced strains, induced primarily by seismic wave passage. Typically, the areas of highest stress are found at offset locations as a result of applied moments (primarily due to axial loads into an elbow or tee) and/or at transition locations near entry into buildings or subgrade vaults as a result of seismic anchor movements and/or differential settlement.
This paper examines the relative influence of the number of diameters of straight piping between offsets and the number of diameters of straight piping in between building/vault entry and the first support on resulting seismic piping loads.
Experiment Verification of Seismic Isolation Device Having Charging Function
Authors: Yamaguchi Takashi , Nakakoji Hayato , Miura Nanako , Sone Akira 
Published: October 2017

In late years, many base isolated structures are planned as seismic design, because they suppress vibration response significantly against large earthquake. In addition, to achieve greater safety, semi-active or active vibration control system is installed in the structures as. Semi-active and active vibration control systems are more effective to large earthquake than passive one vibration control system in terms of vibration reduction. However semi-active and active vibration control systems cannot operate as required when external power supply is cut off. To solve the problem of energy consumption, we propose a self-powered active seismic isolation device which achieves active control system using regenerated vibration energy. This device doesn’t require external energy to produce control force.
The purpose of this paper is to propose the seismic isolation device having charging function and verified its performance by experiment. In our previous research[1], we proposed the new model and optimized the control system and passive elements such as spring coefficients and damping coefficients using genetic algorithm. As a result, we proposed the model which is superior to the previous model in terms of vibration reduction and energy regeneration.
In this study, we conducted an experiment and show its results. As a results, we confirmed the vibration reduction and energy regeneration of the seismic isolation device having charging function.
Development of Manufacturing Technologies for the ITER Toroidal Field Coil: Effort for Precise Manufacturing
Authors: Nishijima Yasushi , Hara Daisuke , Kamitani Keisuke , Tsubota Shuho , Toyoda Masahiko , Baba Takashi , Matsumoto Takashi , Kanbayashi Shigeru , Ando Shinji , Matsui Kunihiro , Nakahira Masataka , Koizumi Norikiyo 
Published: October 2017

Series production of the toroidal field (TF) coils for the ITER has been launched since Oct. 2013. In advance of manufacturing of the actual products, we have performed the preliminary tests and mock-up tests to clarify and confirm the conditions of the welding and machining processes. The ITER TF coil is a welded-structure to endure strong magnetic forces, and it is a huge component in the ITER machine with dimensions of 16.5m height and 9.0m width and a weight of more than 300 ton per coil. In addition, dimensional requirements to the TF coil are very tight from a view point of stable plasma confinement.
In the following section, features of the ITER TF coil are briefly introduced, and performance tests of manufacturing technologies such as welding processes are described, and typical results are summarized. In order to suppress welding deformation, combination method of Tungsten-inert gas welding (TIG) and beam welding (such as an Electron Beam Welding (EBW) and a Laser Beam Welding (LBW)) has been applied to a thick plate weld. Furthermore, process conditions of the EBW and LBW suitable for the thick plate have been investigated to improve work efficiency.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 2 — Evaluation of Lifetime
Authors: Aida Kiyoshi , Minagawa Keisuke , Tanaka Go , Fujita Satoshi 
Published: October 2017

In 2011, Great East Japan Earthquake that is the largest earthquake ever observed occurred. The earthquake had large energy, long duration time and many aftershocks. Huge tsunami caused nuclear accidents. At present, a large number of nuclear power plants in Japan have not been operated yet. Then the base load power in Japan was shifted from nuclear power to coal-fired thermal power. Therefore it is very important to improve aseismic performance of coal-fired thermal power plants.
Boiler structures in coal-fired thermal power plants are generally high-rise structures. In addition its combustion temperature is very high, so boilers are simply suspended from the top of the support structures in order to allow thermal expansion. Therefore boilers easily vibrate. In order to suppress vibration of boilers during earthquakes, stoppers are set between boilers and support structures. The stoppers are made of steel, and dissipate vibration energy by plastic deformation. However aseismic requirements for thermal power plants against large earthquakes having large numbers of repeat counts have been increased.
Then authors have developed a vibration control damper for coal-fired power plants. The damper is set instead of conventional stopper made of steel, and it is able to perform in earthquakes with relatively large numbers of repeat count. Construction of the damper is similar to oil dampers, but inner fluid is viscous fluid.
In this paper, a seismic response analysis using an analysis model of a boiler structure is conducted. The analysis model has plural stoppers or plural dampers. The response analysis result is arranged to investigate lifetime of the stoppers or the dampers. The accumulated plastic displacement of each stopper or damper is used for the evaluation. As a result, it was confirmed that the proposed damper has high durability compared with conventional stopper made of steel.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 3 — Evaluation of Vibration Control Performance
Authors: Minagawa Keisuke , Aida Kiyoshi , Tanaka Go , Fujita Satoshi 
Published: October 2017

After Great East Japan Earthquake in 2011, the base load power in Japan was shifted from nuclear power to coal-fired thermal power. Stable electricity supply is one of important infrastructure, so improvement of seismic reliability of coal-fired thermal power plant and related structures is very important.
Boiler structures in coal-fired thermal power plants are generally high-rise structures, and boilers in the structures are usually hung on the top of the structures in order not to restrict thermal expansion. Therefore boilers easily vibrate by earthquakes. In order to suppress vibration of boilers during earthquakes, stoppers made of steel are installed between boilers and support structures. The stoppers have simple mechanism and dissipate vibration energy by plastic deformation of steel material. However, further improvement of vibration control performance is required from the viewpoint of above-mentioned social requirements and recent large earthquakes such as the Great East Japan Earthquake, the Kumamoto earthquake in 2016 and so on.
This study proposes an application of a damper using viscous fluid to boilers of coal-fired power plants. The damper is set between boilers and support structures. There are many examples of application of the damper using viscous fluid to buildings and civil engineering structures. Therefore the application of the damper to boilers will be effective.
In this paper, a seismic response analysis using an analysis model of a boiler structure is conducted. The analysis model has plural stoppers or plural dampers. The response analysis result is evaluated from the viewpoint of vibration control performance. In other words, story shear force of the support structure is evaluated. In addition various limitations such as the maximum stroke of the dampers are taken into account. As a result, story shear force of the support structure with the proposed damper is smaller than that of the structure with the conventional stopper made of steel, so the proposed damper has high vibration control performance.
Welding Consumables for 2.25Cr-1Mo-V Refining Reactors
Authors: Takauchi Hideaki , Nakanishi Tomoaki , Nako Hidenori 
Published: October 2017

Owing to the demands for larger-capacity reactor vessels in petroleum plants and higher temperature processes for the upgrade of heavy oil, enhanced 2.25Cr-1Mo, 2.25Cr-1Mo-V and 3Cr-1Mo-V steels, which suit both high temperatures and pressure operations, have been developed and used for heavy-wall pressure vessels since the 1990s. 2.25Cr-1Mo-V steel, which has very special mechanical properties, resistant to both hydrogen attack and embrittlement under high temperatures and pressure environments in particular, has been used since 2000. The specifications for 2.25Cr-1Mo-V steel pressure vessels, such as ASME Sec. VIII and API RP 934-A, have been established and reviewed to enhance the contents [1–2].
In this report, the transition of materials, the welding techniques for hydrocracking reactors and 2.25Cr-1Mo-V welding materials are introduced. Particularly, for these welding materials, in order to improve the creep rupture and temper embrittlement properties, the effectiveness of precipitates is discussed. It was found that fine carbide (MC) in crystal grains improves creep rupture lifetime and MC at the prior austenite (γ) grain boundaries inhibits temper embrittlement caused by the segregation of impurities.
Stress Intensity Factors of Pipe-In-Pipes With Circumferential Through-Wall Cracks Based on Elastic Finite Element Analyses
Authors: Kim Se-Chang , Choi Jae-Boong , Huh Nam-Su 
Published: October 2017

Any defects and cracks in pipe-in-pipes (PIPs) applied to deep-water and harsh environment are potential threats that can cause terrible economic damage or environmental pollution as triggering failures.
In the present study, stress intensity factors (SIFs) of PIPs with circumferential through-wall cracks (TWCs) were investigated via detailed 3-dimensional (3-D) elastic finite element (FE) analyses. In terms of the crack location, the cracks are postulated in the inner pipe which is considered as mainly important part to assess the integrity of PIPs. In the present FE analyses, the effects of cross-sectional shapes of both inner and outer pipes on the SIFs of PIPs were systematically evaluated. As for loading conditions, internal pressure, axial tension and bending moment were considered.
The FE results of the SIFs of PIPs were also compared with the existing solution of single-walled pipes with circumferential TWCs to evaluate the restraint effect by the outer pipe on the SIFs of PIPs, where the dimensions of single-walled pipes are assumed to be identical to those of the inner pipe of PIPs.
Repair Welding of Irradiated Reactor Pressure Vessels Steel and Current Direction of Revising JSME Fitness-for-Service Code
Authors: Adachi Hiroyuki , Kimura Ryuji , Kono Yusuke 
Published: October 2017

A primary repair option of Light Water Reactors (LWR) components is welding. However, it is known that welding on steels that have been exposed to neutron irradiation [i.e. Reactor Pressure Vessels (RPV) in PWR and Reactor Internals in BWR] can result in Helium Induced Cracking (HeIC). Helium forms from neutron transmutation reactions of Boron (B) and Nickel (Ni) during operation of the plant.
In order to address this issue and establish verified methods for weld repair of irradiated RPV and Reactor Internals materials in Japanese power plants, an investigation denominated WIM (Welding of Irradiated Materials) Project was conducted; the WIM project was carried out between the years of 1997 and 2004 in an analytical conservative manner, correlating the results of weld repaired irradiated materials with the concentration of helium and the heat input used while welding. It was concluded that, under determined conditions, the irradiated materials were able to be successfully welded in accordance with the requirements established in both the JSME and ASME Code Cases. In the light of such discovery, the necessity of establishing and a new code case and revising the standard JSME Rules on Fitness-for-Service concerning the weld repair of irradiated RPV and Reactor Internals steels is currently under investigation.
Fluid Damping in Fuel Assemblies
Authors: Moussou Pierre , Guilloux Adrien , Boccaccio Eric , Ricciardi Guillaume 
Published: October 2017

Damping is known to be a major parameter in the seismic design of nuclear facilities. Of special interest is the case of fuel assemblies in PWR plants, which, unlike other components, are submitted to axial flows: it has been known since the late 80s that their frequency response to lateral excitations was largely dependent on the flow velocity, and the issue raised by this observation is to determine a consistent fluid force model which could be used in seismic design.
In the scientific literature, the standard model of fluid forces exerted upon an oscillating slender body was originally derived by Lighthill, and it involves a lift coefficient which, up to a reference frame shift, describes the force generated by a small angle of inclination of the body axis against the flow direction. Recent works by Divaret et al. have provided a value of this lift coefficient equal to 0.11 for a single cylinder, and to 0.18 for a square array of 5 by 8 cylinders, the Reynolds numbers being in the range of 104.
Sticking to the idea that the damping stems from the local angle of inclination of the structure against the flow direction, the present study revisits recent tests performed in the Hermes test rig of CEA Cadarache, where a fuel assembly was submitted to incipient flow velocities varying from 1.5 to 5m.s−1, and to a lateral force exerted upon the middle grid, generating displacements in the ranges of a few mm and of a few Hz. Under the assumption that the fuel assembly behaves in an approximately linear manner and that it undergoes harmonic deformations close to its first natural mode shape, the dissipative fluid force can be expressed by an adequate combination of the hydraulic cylinder force and of the structure displacements. A lift coefficient equal to 0.3–0.4 is obtained with this procedure, which stands for the overall fuel bundle, rods and grids included.
Sufficiency of Reference Stress Solutions for FFS Evaluation of Crack-Like Flaws
Authors: Oyamada Kenji , Miura Naoki 
Published: October 2017

In Japan, a new standard of an assessment procedure for crack-like flaws in pressure equipment at elevated temperature is now under development in the High Pressure Institute of Japan (HPI). In this standard development, it is needed to adopt reference stress solutions for crack-like flaws in pressure equipment being subjected to membrane stress and/or bending stress. Such reference stress solutions have been proposed in various references such as ASME FFS-1/API579-1, BS7910, R5, FBR draft guideline, HPIS Z101-2, etc.
A comparative study of those reference stress solutions was conducted in order to select appropriate one. As a result, reference stress solutions in HPIS Z101-2 were adopted. The sufficiency of adopted reference stress solutions was introduced in this paper.
Also, the reference stress solutions for axially and circumferentially through-wall rectangular flawed cylinders, which were not provided in the HPIS Z101-2 standard but were utilized to derive those solutions adopted in the standard, were introduced in this paper. These solutions should be adopted in a new HPI standard for crack-like flaws in pressure equipment at elevated temperature.