bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation of Elastic Fracture Mechanics Parameters Accounting for Residual Stresses
Authors: Boulay Antoine , Pellet Laure , Bargellini Renaud , Lei Yuebao 
Published: January 2014

Most manufacturing processes induce residual stresses in metallic parts which can have a detrimental influence on the in service behaviour and on the integrity of structures. A good consideration of residual stresses is necessary to ameliorate the integrity of structures by avoiding unexpected failures and to have a better understanding and evaluation of the margins remaining in structures strength.
This paper addresses the evaluation and the cross-validation of formulations available in Code_Aster and ABAQUS accounting for the effect of residual stresses in the prediction of elastic fracture mechanics parameters: J-Integral (J) and energy release rate (G).
The latest versions of ABAQUS (from 6.11) and Code_Aster (from STA11.3) allow the effect of residual stresses to be considered in the calculation of the elastic J-Integral and energy release rate G. Contrary to the previous versions, the path-independency of the parameters (J and G) ensure reliable results both in 2D and 3D.
Experimental Investigation on Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Combined Bending and Torsion Loads
Authors: Li Yinsheng , Hasegawa Kunio , Sakai Michiya , Matsuura Shinichi , Miura Naoki 
Published: January 2014

When a crack is detected in a nuclear piping system during in-service inspections, the failure estimation method provided in codes such as the ASME Boiler and Pressure Vessel Code Section XI or JSME Rules on Fitness-for-Service for Nuclear Power Plants can be applied to evaluate the structural integrity of the cracked pipe. In the current codes, the failure estimation method for circumferentially cracked pipes includes bending moment and axial force due to pressure. Torsion moment is not considered.
The Working Group on Pipe Flaw Evaluation for the ASME Boiler and Pressure Vessel Code Section XI is developing guidance for combining torsion load within the existing solutions provided in Appendix C for bending and pressure loadings on a pipe. A failure estimation method for circumferentially cracked pipes subjected to general loading conditions including bending moment, internal pressure and torsion moment with general magnitude has been proposed based on analytical investigations on the limit load for cracked pipes. In this study, experimental investigation was conducted to confirm the applicability of the proposed failure estimation method. Experiments were carried out on 8-inch diameter Schedule 80 stainless steel pipes containing a circumferential surface crack. Based on the experimental results, the proposed failure estimation method was confirmed to be applicable to cracked pipes subjected to combined bending and torsion moments.
Verification of the Linear Matching Method for Limit and Shakedown Analysis by Comparison With Experiments
Authors: Ure James , Chen Haofeng , Tipping David 
Published: January 2014

The Linear Matching Method (LMM), a direct numerical method for determining shakedown and ratchet limits of components, has seen significant development in recent years. Previous verifications of these developments against cyclic nonlinear finite element analysis have shown favourable results, and now this verification process is being extended to include comparisons with experimental results.
This paper presents a comparison of LMM analysis with experimental tests for limit loads and shakedown limits available in the literature. The limit load and shakedown limits were determined for pipe intersections and nozzle-sphere intersections respectively, thus testing the accuracy of the LMM when analysing real plant components. Details of the component geometries, materials and test procedures used in the experiments are given. Following this a description of the LMM analysis is given which includes a description of how these features have been interpreted for numerical analysis. A comparison of the results shows that the LMM is capable of predicting accurate yet conservative limit loads and shakedown limits.
RCC-MRx — Addenda 2013: Feedback of Application of the Code — Developments of Rules to the Evolution of Projects Needs
Authors: Pétesch C. , Lebarbé T. , Bonne D. , de la Burgade F. , Blat-Yrieix M. 
Published: January 2014

The 2012 edition of the RCC-MRx Code has been issued in French and English versions by AFCEN (Association Française pour les règles de Conception et de Construction des Matériels des Chaudières Electro-nucléaires). This Code is the result of the merger of the RCC-MX 2008, developed in the context of the research reactor Jules Horowitz Reactor project, and RCC-MR 2007 which set up rules applicable to the design of components operating at high temperature and to the Vacuum Vessel of ITER.
A significant work has been performed in 2012 and early 2013 to improve the code in order to facilitate its use and understandability, and also to have a better fit with feedback of the main projects (ASTRID, RJH,…). This paper presents the assessment of application of the RCC-MRx and the amendments introduced by the 2013 addenda of the Code.
Application of the Creep Italian Standard Through an Automatic Procedure and Comparison With the American Code
Authors: Grisolia Ottaviano , Scano Lorenzo 
Published: January 2014

A previously-developed computer program [1] features the least-squares analysis for finding the best fitting model’s regression coefficients: The analysis is acted on points (test temperature, ultimate strength at 100000 hours) available in literature for any creep-sensitive material. The automatic procedure gives time to rupture at operation temperature directly through the model chosen for the curve Larson-Miller parameter (LMP) – stress. It applies the first-choice method in the Section II of the guideline [2] to the Italian technical procedure for creep-operated pressure vessel components [3].
Aim of the present work is to compare the results of the Italian code with those predicted by the API 579-1 standard [4]. Comparison is on data gathered by one author in his previous work [5]. That investigated a high energy pipeline after 230000 hours of service and calculated critical components’ life through an API 579-1 Level-3 assessment. Present study uses stresses from standard analysis based on B31.1 code [6] and from a finite element analysis (FEA, elastic and plastic): it finds out the residual life of three components, a 90-LR bend and two tees. Besides, it carries out creep assessment according to the Italian procedure and API 579-1 (Level 1 to 3); the former is LMP-approach based whereas the latter uses both LMP and the Omega methods.
For the Level-1 assessment (B31.1 stresses), the Italian procedure and the API 579-1 return consistent results. Acting a Level-2 assessment through an elastic FEA, results are consistent only when the API 579-1 analysis adopts the Omega Method. The LMP-approach method (minimum stress to rupture data) shows instead more conservative results. API 579-1 Level-3 assessment incorporates creep, plasticity and relaxation: When compared with the Italian procedure it predicts longer creep lives (up to a factor of ten).
Overview of International Implementation of Environmental Fatigue
Authors: de Haan - de Wilde F. H. E. , Hannink M. H. C. , Blom F. J. 
Published: January 2014

For many nuclear power plants worldwide the operation period will be extended from 40 to 60 years in the coming years. As the operation period increases the importance of knowledge of ageing mechanisms like fatigue increases. Knowlegde of the influence of the environment is crucial, since environmental fatigue is a relatively new development which is a modification to the existing assessment method and has to be projected to 60 years as well.
This paper contains the results of a literature survey of environmentally assisted fatigue in nuclear power plants. It describes the current status and developments in the world. The main regulatory rules, guidelines and methods from the US, Germany, Japan, Finland and France are presented.
At this moment different approaches for incorporating the effect of the coolant water environment exist, although the general trend is towards a more uniform approach worldwide. The most common approach is the incorporation of an environmental fatigue correction factor (Fen) in the fatigue derivation of the cumulative usage factor. The Fen formulas and the S-N fatigue curves differ but the general equations are:
Fen = N air / N water
and
CUF = Σ U partial * Fen partial
Alternatives like using fatigue curves including the environmental effects, using threshold criteria and calculation of an allowable Fen based on testing, are described.
Research and material tests are still on-going and subject of international development. An overview of the current international state-of-the-art is presented.
Image Quality Assessment of Four Different Computed Radiography Systems for NDT Applications
Authors: Peterzol Angela , Bader Bruno , Banchet Julien , Caperaa Claire , Didier Vivian 
Published: January 2014

Computed radiography (CR) is a digital radiographic technique, which uses very similar equipment to conventional radiography except that in place of a film to create the latent image, an imaging plate (IP) made of a photostimulable phosphor is used [1].
CR systems are commonly used in medical applications since they have proven reliability over more than two decades. Conversely, the NDT community has discussed the efficacy of film replacement by CR for more than 15 years. Though some standards were introduced in 2005 (ASTM E 2033, CEN EN 14784-2) and others are on the way (PR ISO 17636-2), CR is actually not included within the French RCCM, while the technique is commonly used in US for nuclear applications according to ASME (Section V, article 2).
Since 2006, AREVA has been evaluating the performance of CR in comparison to conventional RT in the framework of EN 14784 for the digital part and the RCCM for the conventional part. The objective was to build a technical justification report to eventually support introduction of CR into the RCCM.
In 2009 the subject gave rise to collaboration between AREVA NP – NETEC and EDF-CEIDRE, for a joint project to establish performance limits of CR towards EN 14784 specifications and RCCM image quality indicator (IQI) requirements [2]. In this paper, we present performance comparison results of four different CR systems. The measurements were conducted in 2012 and they demonstrate the current state of achievable image quality in CR. The performance has been evaluated for steel with a thickness range of 20÷60 mm using an Iridium 192 gamma source. Image quality has been assessed in terms of EN 462 and ASTM (E 747, E 1742) IQI. The results have been scored considering the PR ISO 17636-2, RCCM 2007, and ASME V-2010. This also permitted comparison among the different standard requirements.
A Technical and Economic Comparison of Raised Face Versus Ring Joint Flanges
Authors: Reichert Christopher D. , Messer Barry , Reichert Larissa C. 
Published: January 2014

On new construction projects, designers are frequently faced with the choice of whether to use raised face or ring joint flanges for piping systems. Often, decisions are made based on flange types used in the past, without due consideration for the merits of either style. On major piping projects, the decision can have significant and far reaching impacts for the owner of the facility, from a cost, constructability, and operational point of view.
The authors of this paper studied several recent projects in North America and Europe and performed a technical comparison of the strengths and weaknesses of each style of flange. The authors also performed a comprehensive estimate of the cost differential between using the different styles of flanges. The provision of both technical and economic data in one paper is intended to provide a resource of data that designers need to make an informed decision about which style of flange to use.
Validation of the Accuracy of Approximation in a Design Formula for an Air Spring by Using Numerical Analysis
Authors: Asami Toshihiko , Yokota Yasutaka , Okura Masahito , Ise Tomohiko , Honda Itsuro , Sakamoto Hiroya 
Published: January 2014

Previously, the authors proposed an approximation formula for designing an air spring that consists of two air tanks connected by a long pipe. The analysis was based on a linear approximation, so there is no amplitude dependency in the amplitude ratio for the sinusoidal vibration of a system with an the air spring. However, according to the experiment, it was found that there is remarkable amplitude dependency in a system with this type of air spring, so the frequency response curves for the system change with the magnitude of the input amplitude. It became clear that the approximation formula is in agreement with the limit value when the input amplitude approaches zero.
We consider that the deviation between the approximation formula and the experimental results are caused by the various assumptions which used in the analysis. As we remove these assumptions one by one, we perform the numerical analysis based on the finite difference method for this air spring. As a result, it was found that the effects of the turbulent flow in the pipe and the pressure loss at the inlet and outlet of the pipe are very small. A major influence is attributed in the connector that connects the pipe to the air chamber. The flow is throttled and disturbed at the connector whose inner diameter is smaller than the inner diameter of the pipe.
To Determination of the WWER RPV Steels Crack Resistance Characteristics
Authors: Orynyak Igor , Zarazovskii Maksym , Radchenko Sergii , Kozlov Volodymyr 
Published: January 2014

The efficiency of fracture toughness determined by the methodology of normative document PNAE G-7-002-86 has been analyzed.
Crack resistance characteristics of WWER-1000 reactor pressure vessel base metal at unirradiated condition are obtained by experimental way. All specimens were made of the RPV support forging (15Kh2NMFA steel) of abandoned Crimean NPP Fracture toughness experiments were carried out on three types of specimens CT 1T, CT 0.5T and SEB over a temperature range from −130°C to −40°C in fully accordance to the ASTM E1921. Charpy impact energy data obtained on twelve specimens over a temperature range from −80°C to 80°C has been used to determine the 47J transition temperature.
Comparison of obtained fracture toughness data with normative curve shows that the last one has unreasonably high lower shelf. It has been found that the PNAE G-7-002-86 Code, which uses the ideology of transition temperature shift, is too conservative to estimate WWER-1000 RPVs resistance against brittle fracture for the pressurized thermal shock (over 90 MPa·√m area of stress intensity factor).
Steam Methane Reformer Furnace Outlet Manifold Component Repair Experience
Authors: Oza Shaileshkumar H. , Penso Jorge A. 
Published: January 2014

The steam methane reformer of RIL SEZ refinery was commissioned in 2009. Cold header replacement was planned in 2012, due to severe hot spots occurrences. While performing field welds at bull tee to cone material transitions, cracking was experienced when welding static cast tees (20Cr-32Ni-1Nb alloy) to hot header and reducers (cone). Cracks were reported in tees’s heat-affected-zones. Specific weld repair procedures were developed.
This paper discusses the in-service damaging mechanisms that apply to these headers including creep, thermal fatigue, thermal shock, metal dusting, thermal aging embrittlement and reheat cracking. This paper also discusses fabrication discontinuities such as solidification cracks, reheat cracks and ductility dip cracks. Then, the metallurgical analyses completed on the header components are discussed.
Finally, the repairs are described including the learning steps that led to the final successful repair. The following sections of this paper depict how the innovative engineering solution was arrived at, analyzing the risks of continued operation, inspection, monitoring, and finalizing the strategy for on-line repair to sustain operation.
Derivation of the Depth Dependent Mechanical Characteristics of Ion-Irradiated F82H Steels by Using a Finite Element Analysis
Authors: Kim Jongmin , Shin Chansun , Noh Sanghoon , Lee Bongsang 
Published: January 2014

Changes in mechanical material properties caused by neutron irradiation during the nuclear power plant operation are one of the key safety issues for the maintenance and long-term operation of nuclear power plants (NPPs). Ion-irradiation is widely used to simulate neutron irradiation condition in laboratory environment, such an irradiation effect on the material property is varied along the depth of a material subjected to ion irradiation. Since the ion irradiation induces a depth-dependent dose from the surface of a material. The load-depth (L-h) curve and nano-hardness measured from nanoindentation, which is used to obtain the material properties using small specimen, normal to the ion-irradiated surface is a result of complex average of varying mechanical property along the indentation depth.
The present paper investigates a method to evaluate depth (or dose)-dependent mechanical properties by combining experiment and finite element (FE) analysis of nanoindentation. The method is applied to reduced activation ferritic-martensitic steel, F82H. The material was ion-irradiated using Fe3+ ions of 1.7 MeV accelerating voltage at 300°C. The applicability of reverse algorithm was reviewed, and separate FE analyses were performed to determine material parameters by using trial set of material parameters. The ion-damaged surface layer was divided into several layers in the FE modeling. The L-h curve using determined stress-strain curve by using trial set of material parameters was found to be better agreement than reverse algorithm with experimentally measured one by nanoindentation. The advantage and limitation of the method investigated in this study will be discussed in detail.
Experimental Investigation of Friction Stir Seal Welding of Tube-Tubesheet Joints
Authors: Al-Badour Fadi A. , Merah Nesar , Shuaib Abdelrahman , Bazoune Abdelaziz 
Published: January 2014

To ensure heat exchanger tube-tubesheet joints tightness, industrial standards may recommend performing a combination of roller expansion and seal welding, using conventional fusion welding processes. Solid state friction stir welding (FSW) has several advantages over the conventional fusion welding but has not yet proven its usefulness in seal and strength welding of heat exchanger tube-tubesheet joints where the available space is very limited and weld pass is of a relatively complex contour.
In this work, a newly designed tool and procedure are applied to friction stir seal weld (FSSW) tube-tubesheet joints. The effects of process conditions such as welding speed and tool offset on dependent process parameters including welding loads and joint quality are investigated on a 600-series aluminum three-tube test cell.
The results revealed that the quality of the seal weld of tube-tubesheet joints is affected by the preceding parameters at different levels.
Predictions of Creep Crack Initiation Periods in Pre-Compressed 316H Stainless Steel
Authors: Tarnowski K. M. , Davies C. M. , Webster G. A. , Dean D. W. 
Published: January 2014

Pre-compression of 316H stainless steel significantly alters its tensile, uniaxial creep and crack growth behaviour. It has previously been shown that reliable and conservative creep crack initiation predictions can generally be obtained for as-received 316H stainless steel using a variety of prediction methods. Given the changes in material behaviour caused by pre-compression, this paper applies similar prediction methods to pre-compressed 316H stainless steel at 550°C.
Several procedures are available for estimating creep crack initiation time periods. The suitability of a procedure depends on the availability of the necessary material data. The procedures considered in this paper include the use of the creep fracture mechanics parameter C*, the crack opening displacement concept, the sigma-d approach and the time dependent failure assessment diagram.
Creep crack growth tests have been performed on compact tension specimens manufactured from 316H stainless steel which was uniformly pre-compressed by 4% and 8% at room temperature. For each test, the time for creep crack initiation to occur was recorded. Predicted creep crack initiation times have been compared with the experimentally determined values. Comparisons with as-received material are also included.
For pre-compressed material, conservative creep crack initiation predictions were only consistently achieved using steady state creep crack growth rates predicted from C*. This is a significant difference to as-received material for which conservative predictions were generally obtained by a variety of methods. At this time, there is only a limited set of pre-compressed data making it difficult to draw firm conclusions about the appropriateness of the various creep crack initiation prediction methods. The differences in the results between the pre-compressed and as-received material do however highlight the need for further tests on pre-compressed material.
Overview of the Fatigue Design Discussions in the United States From These Past 10 Years
Authors: Harrison Harry , Gurdal Robert 
Published: January 2014

The topic of fatigue is probably the topic that has been discussed the most in the U.S. these past ten to fifteen years during the ASME-Code Meetings. It seems now that the rules dictated by the U.S. NRC will be final in the U.S. sometime during the year 2014. These final rules could possibly have an influence on the other countries, although some of these other countries have already noticed that these Fatigue Rules are very severe, especially when penalizing the ASME-Code usage factors by the environmental F(en) factors proposed by the U.S. NRC and the associated procedures.
The purpose of this paper is to describe some of the past and on-going discussions taking place in both the United States and Europe, and to present the most important comparison Figures, as far as those new Rules are concerned. These comparison Figures are for both in-air fatigue design and fatigue design with the consideration of the environmental effects. Comparisons need to be performed, for example, between past component fatigue tests and the new fatigue Rules provided by the U.S. authorities.
In addition, suggestions for future simplified rules are presented in this paper. These simplified Rules are for the fatigue design when using the ASME-Code from the U.S. or a modification of the current ASME-Code fatigue methodology in case the severe F(en) factors need to be applied.