bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Mitigation Technique to Reduce Stress at Pipe Welds Caused by Acoustic Induced Vibrations (AIV)
Authors: Ridens Brandon L. , Simons Sarah B. 
Published: November 2019

Abstract
Within blowdown and pressure relieving systems, a phenomenon known as acoustic induced vibrations (AIV) increases the risk of costly failures at branch connections, pipe supports and other discontinuities downstream of pressure relieving devices. Broadband pressure fluctuations generated during these AIV events lead to elevated stresses at welded connections. Based on recent research, modeling and measuring the effects of AIV in piping systems, it is possible to reduce the dynamic pressure fluctuations that cause AIV closer to the excitation source. This can lead to more cost effective and efficient means of reducing the likelihood of failures caused by AIV.
This paper will discuss the results of full-scale testing of a novel mitigation technique that reduces pressure fluctuations that cause AIV. The reduction in dynamic pressure leads to significant lowering of the overall stresses near the pipe welds at discontinuities. In addition, results indicate that a reduction in dynamic pressure can be obtained with the mitigation technique tested to a level acceptable by current screening methods.
Finite-Element Analysis of Contact Stress at the Bearing Surfaces in Bolted Joints (Effect of Flange Bolt Shape and Dimensions)
Authors: Shirakawa Atsushi , Sawa Toshiyuki 
Published: November 2019

Abstract
A higher bolt preload is desirable for higher integrity of bolted joints. However, the bearing surface in the joints could be permanently deformed under a higher preload and the bolt preload decreases with an increase of permanent deformation. Various materials are used as clamped parts, so the permanent plastic deformation should be examined for each material clamped parts. In addition, the critical contact stresses should be examined for various clamped materials. In the previous paper, it was found that the relationship between the contact stress when the plastic deformation initiated, and the compressive proof stress of the clamped parts is linear. However, this conclusion was due to the specific bolt shape and dimensions. In the present paper, the effects of shape and dimensions of bolt head on the contact stress and deformation are examined. This applies to normal and undercut type bolts with sloped bearing surfaces. FEM calculations were used and the clamped part materials were steel and aluminum alloy. Also, a new contact area ratio at the bearing surface is defined and investigated because the nominal contact area is different from the actual contact area when the bolt bearing surface is sloped. Finally, discussion is made on an appropriate contact area, and critical contact stress at the bearing surface as well as suitable bolt shape and bolt head dimensions.
A Case Study: A Systems Approach for 20ksi Equipment Qualification
Authors: Raney James B. , Walz Gregg , Kaminski Dennis 
Published: November 2019

Abstract
Beginning in August 2013, Anadarko Petroleum formed the “20A Project Initiative” for qualifying 20 ksi equipment for a Deepwater Gulf of Mexico (GoM) development. This paper will cover the systems approach used for the qualification (verification, validation and quality) of a system of components, including sub-assemblies and assemblies that are required for a 20 ksi development. The systems approach begins with the framework and management of this framework inside the overall development process. The systems approach categorizes each component by mode of operation (many pieces of equipment are used in multiple operational modes). These modes of operation are Drilling, Completions, Production and Intervention, and are the engineering systems used to manage the qualification of over 200 components to industry standards and U.S. government requirements. The functional requirements for each component are defined and vendors selected. Each component is then stewarded through a project-management process for design, verification, validation and quality. This process culminates with the integration of these components back into a system that can be qualified for use in an HPHT environment. This paper addresses the submittal to regulatory authority for approval to use the newly developed and qualified 20 ksi equipment for a deepwater GoM development.
This project ends in 2019. This six-year development journey presented challenges and achieved breakthrough technologies for the industry. This journey, its organizational approach using systems engineering techniques and integration processes are presented.
Effect of Deformation of Core Elements of Fast Reactor Core to the Seismic Response
Authors: Iwasaki Akihisa , Matsubara Shinichiro , Kawamura Kazuteru , Harada Hidenori , Yamamoto Tomohiko 
Published: November 2019

Abstract
Core elements of a fast reactor are self-standing on the core support structure and not restrained in the axial direction. When the earthquake occurs, it is necessary to consider vertical behavior and horizontal displacement of the core elements simultaneously. In the core seismic analysis, a three dimensional core vibration behavior was evaluated by considering fluid structure interaction, collision with adjacent core elements and vertical displacement and verified by a series of vibration tests. But the evaluation had a assumption of straightness of each core elements which may be bowed due to thermal expansion and swelling under restraint of the horizontal direction between the upper pad and lower structure (Entrance Nozzle). If the core elements are deformed in its plant operation, they may push each other against its adjacent core elements. The large horizontal interference forces may work to decrease the vertical displacement of the core elements.
In this study, to grasp and estimate the behavior under the deformed core elements under the earthquake motion, a three dimensional seismic analysis model consist of all of core elements with consideration of the effect of deformed core elements were prepared, analyzed and verified by hexagonal-matrix tests with 37 core elements and single row mock-up models with 7 core elements. These test results show that the rising displacements decrease with increased deformation and no rising occurs when the deformations exceed a threshold.
In this paper, the effect of bending deformation due to thermal expansion and swelling on the rising displacement of the core elements was shown by seismic experiments.
Development of Active Vibration Damping Device Adjusting TMD to Various Periodic Bands of Seismic Waves
Authors: Watanabe Kota , Miura Nanako , Sone Akira 
Published: November 2019

Abstract
There are many high-rise buildings all over the world, especially urban areas. Their usage is diverse, such as offices and residences. Therefore, earthquake countermeasures for high-rise buildings are indispensable. It is known that a tuned mass damper (TMD), which is mainly installed for countermeasures against wind shaking, does not show sufficient damping effect when large earthquake occurs or when higher modes vibration is excited. In addition, when exceeding the drive limit of the TMD in resonance, the TMD may collide against the stopper and deteriorate the response of the building. There are some researches targeting building with TMD, and many of them aim at developing new devices. However, installing a new equipment instead of TMD requires a lot of cost and construction period. Therefore, in this research, an active device that can be attached to TMD is developed. Moreover, validity is examined by numerical simulation. In this paper, parameters of the passive elements are verified as a basic research of the proposed device.
Dynamic Response Analysis of Beam Mode Vibration of Piping System due to Turbulent Flow Around Bend
Authors: Kataoka Shunji , Matsuura Kota , Qian Shaoxiang 
Published: November 2019

Abstract
Prevention of piping vibrations during design stage has attracted attention recent years. Though the piping vibration occurs due to various mechanisms, the vibration due to fluid turbulence is one of a major topic discussed. The pressure fluctuation due to fluid turbulence occurs around flow discontinuities such as branches, elbows, flow expansions and valves, and the fluctuation can cause the piping vibration and both shell mode and beam mode vibration can occur. Guideline published by Energy Institute UK[1] (EI-AVIFF) shows a method to check the possibility of piping vibration due to flow induced turbulence and it gives some information on recommended piping span. The method is quite useful for screening purpose to select the piping system with potential vibration risks. However, it is known that the guideline is based on very conservative assumptions, as 90-degree miter bend, and it results in overdesign of piping systems, so more detailed vibration assessment approach succeeding the screening is demanded.
In this paper, the method of detailed beam-mode piping vibration assessment using finite element dynamic structural analysis and Large Eddy Simulation (LES) based CFD are discussed. As an example, LES based CFD analyses were conducted on 90 degrees single miter bend, long and short elbow. The resultant pressure fluctuations are compared to past published report and good agreement was confirmed. The CFD results were reorganized and piping dynamic analysis were conducted. Based on these analysis results, the detailed piping vibration risk assessment method using CFD and dynamic structural analysis are proposed.
Advances Towards Elastic-Perfectly Plastic Simulation of the Core of Printed Circuit Heat Exchangers
Authors: Katz Alon , Ranjan Devesh 
Published: November 2019

Abstract
Printed circuit heat exchangers (PCHEs) are used in a number of novel nuclear reactor designs. In order to use a PCHE as a primary coolant confinement unit in the United States, the stress and strain must be modeled under realistic service loads, and shown to remain within limits imposed by ASME standards. Due to the complex geometry and multi-length scale features, direct simulation of the stress and strain in a utility scale PCHE is not practical because of the large number of degrees of freedom. This work presents an algorithm to model damage to the core region of a PCHE using planar 2D formulation and realistic service loads. We compare how closely the results from three different planar formulations match the results of a corresponding 3D model. We also explore other ways of reducing the size of the numerical model required to accurately simulate the stress and strain in the core region of a PCHE. Finally, we perform strain-limits evaluation on a core region of a PCHE using fully temperature coupled, elastic perfectly plastic material properties, and realistic service loads, obtained from plant dynamics code of sodium cooled fast reactor coupled with a supercritical CO2 Brayton cycle. For our analyses, we used CSIMSOFT Trelis: a commercial meshing software, Multi Object Oriented Solver Environment (MOOSE): an open source finite elements solver, and Paraview: an open source post processing tool. Our methodology is presented and discussed in sufficient detail so that the work can be reproduced by others.
Characterization of Piezoelectric Material Properties Using Atomistic Simulations
Authors: Park Y. H. , Hijazi I. 
Published: November 2019

Abstract
Damage monitoring in pipes and pressure vessels are important to ensure safety and reliability of these structures. Structural damage monitoring based on an actuator-sensor system is a promising technology to obtain real-time information for structural condition. Since piezoelectric materials in electromechanical systems can detect mechanical responses such stress and deformation as a sensor or perform a defined work as an actuator, piezoelectric actuators/sensors are extensively used in damage detection. In the design of piezoelectric actuators and sensors, it is important to know the properties of the piezoelectric material, in particular, piezoelectric constants to predict its actuation/sensing performance. In this study we determine a piezoelectric constant of ZnO using molecular dynamics simulations. We introduced a shell degree of freedom to the core-only atomic potential to enable polarization of the ion caused by an electric field. This modeling technique allowed for accurate piezoelectric response of the molecular structure.
A Proposal of Inelastic Constitutive Equations of Lead Alloys Used for Structural Tests Simulating Severe Accident Conditions
Authors: Hashidate Ryuta , Onizawa Takashi , Wakai Takashi , Kasahara Naoto 
Published: November 2019

Abstract
This paper studies inelastic stress-strain relationship equation and creep rupture equation and creep strain equation of 99%lead-1% antimony alloy. Under the severe accident conditions, structural materials of nuclear power plants are subjected to excessive high temperature. Although it is very essential to clarify how the structure collapses under the severe accident conditions, there’re no experimental evidences of failure modes and the failure mechanisms in such high temperatures are not clarified. However, it is very difficult and expensive to perform structural tests using actual structural materials, such as austenitic stainless steels. Therefore, the authors propose to use lead alloys instead of actual structural materials. Because the strength of such alloys is much poorer than that of the actual structural materials, failure can be observed at much low temperature and by much small load.
For demonstration of analogy between the failure mechanisms of lead alloy structure at low temperature and those of the actual structures at extremely elevated temperature, numerical analyses are required. The authors proposes inelastic constitutive equations of lead alloy based on a series of material tests. Nonlinear numerical analyses, e.g. finite element analyses, can be performed using the proposed equations.
Buckling and Fatigue Evaluation of Braced Piping Support by Numerical Analysis
Authors: Shimazu Ryuya , Sakai Michiya 
Published: November 2019

Abstract
Buckling and fatigue evaluation of braced piping supports was conducted using numerical analysis. Buckling and fatigue occurred on the piping support during vibration and static load tests. A numerical model for the evaluation was developed, and the load–displacement relationship and local strain obtained by the numerical analysis were in good agreement with experimental results. Thus, the numerical model was validated. Buckling and fatigue evaluations were subsequently conducted using the model. In the buckling evaluation, the experimental buckling load was in good agreement with that obtained by Johnson’s formula. Fatigue evaluation was conducted to investigate whether fatigue crack had occurred before the rupture on the piping support. The linear cumulative damage was calculated, suggesting the possibility of fatigue crack formation. Ductile rupture was considered to occur after the fatigue crack formation.
An Update on Quantifying Bolt Relaxation During High Temperature Operation
Authors: Brown Warren , Knight Nathan 
Published: November 2019

Abstract
A summary of testing related to bolt relaxation, which occurs at temperatures above 230°C (450°F) was presented in a previous paper. The work has since been extended to include lower temperature data for common bolting materials. This paper provides a summary of the additional work performed and further observations regarding the acceptable design limits for A193-B7 and A193-B7M bolt materials. In addition, a conclusion regarding the recommendations made in API RP751 comparing A193-B7 and A193-B7M relaxation is made.
HPHT Equipment Stress Intensity Calculation Based Upon the API 579/ASME FFS and ABAQUS J Integral Fracture Mechanics Basis
Authors: Lim Jong IL , Han Young-Hoon 
Published: November 2019

Abstract
Fatigue sensitive pressure containing components in the oil & gas industry requires a life cycle assessment. High Pressure High Temperature (HPHT) equipment designed using API 17TR8 and ASME Section VIII Division 3 are evaluated for cyclic fatigue crack growth per API 579/ASME FFS-1 fitness for service level 3 assessment. The level 3 assessment requires more advanced stress analysis to define the state of stress at critical locations and a defined initial flaw for cycle growth assessment. The cyclic crack growth in pressure containing equipment depends on the alternating crack tip stress intensity values for the defined load histogram. Therefore, in this paper, the stress intensity at crack tip is calculated using two approaches for 20ksi pressure equipment. The first approach is to utilize linear elastic stresses obtained from a three-dimensional finite element evaluation, where the stress profiles are used as an input to Signal FFS (fitness for service) Quest software, to calculate stress intensity at crack tip. The second approach utilizes a J-integral based on fracture mechanics analysis considering a pressure penetration on cracked surfaces. Although there is a difficulty in representing the complete production load histogram applying the J-integral solution, this paper provides evaluation of the two methods for comparison of results. It also demonstrates the feasibility of application to pressure vessel equipment.
Tensile Behavior of 82/182 Filler, Butter and Heat-Affected-Zones in a 508 LAS - 316 SS Dissimilar Weld: Tensile Test, Material Model and Finite Element Model Validation
Authors: Mohanty Subhasish , Listwan Joseph , Majumdar Saurindranath , Natesan Krishnamurti 
Published: November 2019

Abstract
In this paper we present the room temperature tensile test results for 82/182 Filler, Butter Weld and Heat-Affected-Zone in a 508 LAS − 316 SS Dissimilar Weld (DW). Also we present the associated tensile properties and material hardening model parameters; those can be used for future component level stress analysis modes. In addition, we present the finite element (FE) model of the uniaxial DW tensile-test specimens to validate the accuracy of the estimated material model parameters. Through the FE model results, we also explain the importance of various offset strain yield stress in capturing the material behavior in a mechanistic (using FE) modeling approach particularly while modeling the plasticity driven low-strain-amplitude low-cycle-fatigue damage of a structural component.
Hydrogen Induced Cracking of a Dissimilar Weld in a Hydrogen Manufacturing Plant
Authors: Park Neil , Penso Jorge 
Published: November 2019

Abstract
A hydrogen manufacturing plant experienced circumferential cracking at the dissimilar weld on the outlet header. The outlet header was a cold wall design and the dissimilar weld was between HP40 modified and carbon ½ Mo steels. The resultant failure investigation found the cause to be hydrogen induced cracking of the dissimilar weld at the fusion boundary zone. The hydrogen was generated from the CO2 corrosion which occurred due to operating the tubes below the dew point and the hydrogen was trapped in the steel by the CO chemisorption onto the steel. The following paper outlines the failure investigation and the fitness for service conducted to maintain the running of the plant.
PTS Evaluation Case Study Considering Actual Through-Wall Fracture Toughness Distribution
Authors: Yamamoto Masato , Nagai Masaki 
Published: November 2019

Abstract
The surveillance test specified in JEAC4201 requires the fracture toughness evaluation of base metal at 1/4-T thickness and T-L orientation, where the initial fracture toughness generally is the minimum in whole thickness at any orientation. In the present study, actual through-wall fracture toughness distribution from a commercial RPV base metal on both of T-L and L-S (actual through crack orientation) orientations were evaluated from Zion Unit 1, which was decommissioned after 25 years (15EFPY) commercial operation. A base metal block of 40mm(T) × 216mm(L) × 216mm(S) was retrieved from belt line region by effort of ORNL and provided to CRIEPI under the USA - Japan collaborative agreement on civil nuclear research framework called CNWG. Through-wall fracture toughness distribution was characterized by means of the Master Curve method utilized by 4mm thickness C(T) “Mini-C(T)” specimens. Near surface material possessed significantly high fracture toughness at amount of 40 degrees Celsius lower reference temperature (To) than those in center thickness locations, despite of higher neutron fluence gained during service operation. Pressurized thermal shock evaluation by probabilistic fracture mechanics code PASCAL4 demonstrated that through-wall fracture probability can be remarkably lowered by considering through-wall fracture toughness distribution.
Effect of Coolant Water Temperature of ECCS on Failure Probability of RPV
Authors: Katsuyama Jinya , Masaki Koichi , Lu Kai , Watanabe Tadashi , Li Yinsheng 
Published: November 2019

Abstract
For reactor pressure vessels (RPVs) of pressurized water reactors, temperature of the coolant water in the emergency core cooling system (ECCS) may influence the structural integrity of the RPV during pressurized thermal shock (PTS) events. By focusing on a mitigation measure to raise the coolant water temperature of ECCS for aged RPVs to reduce the effect of thermal shock due to PTS events, we performed thermal hydraulic analyses and probabilistic fracture mechanics analyses by using RELAP5 and PASCAL4, respectively. The analysis results show that the failure probability of RPV decreased dramatically when the coolant temperature in accumulator as well as in the high- and low-pressure injection systems (HPI/LPI) was increased, although the increase in coolant temperature in the HPI/LPI only did not lead to a decrease in the failure probability.
Vibration Control of Buildings Using Series Rolling-Pendulum Tuned Mass Dampers
Authors: Wang Jer-Fu , Chen Chun-Hung , Chang Chang-Ching , Lin Chi-Chang 
Published: November 2019

Abstract
This paper proposes a passive vibration control device, series rolling-pendulum tuned mass damper (SRPTMD), with a “ball-in-ball” configuration. A conventional pendulum TMD (PTMD) generally requires a long cable length that usually exceeds one-story height for high-rise buildings. A rolling-pendulum TMD (RPTMD) is a mass that can roll on a base with a curvature instead of swaying with a cable, significantly reducing the requirement of vertical rooms. In addition, a ball-in-ball SRPTMD is equivalent to a system with two degrees of freedom in series. This study aimed to derive equations of motion of the primary building-SRPTMD system, conduct a parametric study for SRPTMD, and investigate the structural control performance of an SRPTMD. Results showed that an SRPTMD performed similarly to an RPTMD. One advantage of an SRPTMD is that the fundamental natural frequency of an SRPTMD can be altered to a certain extent by changing the radius ratio of the inner ball to the outer ball, whereas the natural frequency of an RPTMD can only be altered by changing the curvature of its base, which is far more difficult. Another advantage is that the two modal frequencies of an SRPTMD can be manipulated by selecting a specific set of radius ratios between the base, the outer ball, and the inner ball, which means that an SRPTMD has higher potential on multiple modes control.