Volume 6A: Materials and Fabrication最新文献

{"title":"Pre-Strain Effects on Mixed-Mode Fatigue Crack Propagation Behaviour of the P355NL1 Pressure Vessels Steel","authors":"J. Ferreira, J. Correia, G. Lesiuk, Sergio Blasón González, Maria Cristina R. Gonzalez, A. Jesus, A. Fernández‐Canteli","doi":"10.1115/PVP2018-85089","DOIUrl":"https://doi.org/10.1115/PVP2018-85089","url":null,"abstract":"Pressure vessels and piping are commonly subjected to plastic deformation during manufacturing or installation. This pre-deformation history, usually called pre-strain, may have a significant influence on the resistance against fatigue crack growth of the material. Several studies have been performed to investigate the pre-strain effects on the pure mode I fatigue crack propagation, but less on mixed-mode (I+II) fatigue crack propagation conditions.\u0000 The present study aims at investigating the effect of tensile plastic pre-strain on fatigue crack growth behavior (da/dN vs. ΔK) of the P355NL1 pressure vessel steel. For that purpose, fatigue crack propagation tests were conducted on specimens with two distinct degrees of pre-strain: 0% and 6%, under mixed mode (I+II) conditions using CTS specimens. Moreover, for comparison purposes, CT specimens were tested under pure mode I conditions for pre-strains of 0% and 3%. Contrary to the majority of previous studies, that applied plastic deformation directly on the machined specimen, in this work the pre-straining operation was carried out prior to the machining of the specimens with the objective to minimize residual stress effects and distortions. Results revealed that, for the P355NL1 steel, the tensile pre-strain increased fatigue crack initiation angle and reduced fatigue crack growth rates in the Paris region for mixed mode conditions. The pre-straining procedure had a clear impact on the Paris law constants, increasing the coefficient and decreasing the exponent. In the low ΔK region, results indicate that pre-strain causes a decrease in ΔKth.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132557267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on Stress Rupture Characteristics of CFRP","authors":"Takeru Sano, T. Yamada, T. Takehana, T. Miyashita, Y. Shiga, N. Yoshikawa, Hiroshi Kobayashi","doi":"10.1115/PVP2018-85082","DOIUrl":"https://doi.org/10.1115/PVP2018-85082","url":null,"abstract":"With the widespread use of fuel cell vehicles in recent years, the development of hydrogen containers for vehicles and accumulators for hydrogen refueling stations has been actively carried out. For these containers and accumulators, composite containers using carbon fiber reinforced plastic (CFRP) have become a focus.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133247586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Two Ductile Crack Propagation Models of GTN and CZM for Pipe Steel Fracture","authors":"Junqiang Wang, Haitao Wang, N. Lin, Honglian Ma, Jinlong Wang","doi":"10.1115/PVP2018-84689","DOIUrl":"https://doi.org/10.1115/PVP2018-84689","url":null,"abstract":"The ductile crack propagation behavior of pressure equipment has always been the focus of structural integrity assessment. It is very important to find an effective three-dimensional (3D) damage model, which overcomes the geometric discontinuity and crack tip singularity caused by cracking. The cohesive force model (CZM), which is combined with the extended finite element method (XFEM), can solve element self-reconfiguration near the crack tip and track the crack direction. Based on the theory of void nucleation, growth and coalescence, the Gurson-Tvergaard-Needleman (GTN) damage model is used to study the fracture behavior of metallic materials, and agrees well with the experimental results. Two 3D crack propagation models are used to compare crack propagation behavior of pipe steel from the crack tip shape, fracture critical value of CTOA and CTOD, constraint effect, calculation accuracy, efficiency and mesh dependence etc. The results show that the GTN model has excellent applicability in the analysis of crack tip CTOD/CTOA, constraint effect, tunneling crack and so on, and its accuracy is high. However, the mesh of crack growth region needs to be extremely refined, and the element size is required to be 0.1–0.3mm and the calculation amount is large. The CZM model combined with XFEM has the advantages of high computational efficiency and free crack growth path, and the advantages are obvious in simulating the shear crack, combination crack and fatigue crack propagation. But, the crack tip shape and thickness effect of ductile tearing specimen can not be simulated, and the CTOA value of local crack tip is not accurate.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130071569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D FEM Modeling of Crack Initiation in a Reactor Pressure Vessel During a PTS Event (LBLOCA)","authors":"Diego F. Mora Mendez, M. Niffenegger, G. Qian, M. Jaros, B. Niceno","doi":"10.1115/PVP2018-85024","DOIUrl":"https://doi.org/10.1115/PVP2018-85024","url":null,"abstract":"To perform the integrity assessment of a reactor pressure vessel (RPV) related to Pressurized Thermal Shock (PTS), we model the RPV using the 3D finite element method (FEM). Accurate prediction of temperature and stress fields is determined by using 2-Phase computational fluid dynamics (CFD) simulation in combination with an appropriate finite element discretization of the RPV wall. The cladding and the ferritic low alloy steel are considered as two separated layers, which can be intersected by superficial cracks. The calculation of the stress intensity factor (SIF) in mode I is based on the linear fracture mechanics theory (LEFM) and hypothetical cracks are located in different locations to consider the most critical cases.\u0000 In the present study, the sub-modeling technique is implemented to refine the mesh required by the fracture analysis in the region of interest. Three types of cracks are considered: axial, circumferential and inclined. The performed integrity assessment uses the master curve approach. The stress intensity factor in the deepest point of a surface crack was compared with the material’s fracture toughness. In previous studies the integrity of the RPV subjected to medium and small break Loss-of-Coolant Accident (MBLOCA and SBLOCA, respectively) has been evaluated, therefore the concern in this contribution is the large break of Loss-Of-Coolant Accident (LBLOCA). The combination of 3D FEM with CFD simulations allows us to study the influence of the dynamic cooling plume on the stress intensity in more detail than with the conventional one dimensional method.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128272664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructure-Property Relationships in Powder Bed Fusion of Type 304L Austenitic Stainless Steel","authors":"C. S. Marchi, J. Sugar, Thale R. Smith, D. Balch","doi":"10.1115/PVP2018-84901","DOIUrl":"https://doi.org/10.1115/PVP2018-84901","url":null,"abstract":"Additive manufacturing (AM) includes a diverse suite of innovative manufacturing processes for producing near-net shape metallic components, typically from powder or wire. Reported mechanical properties of materials produced by these processes varies significantly and can usually be correlated with the relative porosity in the materials. In this study, relatively simple test components were manufactured from type 304L austenitic stainless steel by powder bed fusion (PBF). The quality of the components depends on a host of manufacturing parameters as well as the characteristics of the feedstock. In this study, the focus is the bulk material response. Tensile properties are reported for PBF type 304L produced in similar build geometries on two different machines with independent operators. Additionally, the effect of hydrogen on the tensile properties of the AM materials is evaluated. The goal of this study is to provide a benchmark for tensile properties of PBF 304L material in the context of wrought type 304L, and to make a preliminary assessment of the effects of hydrogen on tensile properties.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"2017 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128070629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure Integrity Evaluation of Supercritical Water Cooled Pressure Tube Subjected to Accident Conditions","authors":"Jia-cheng Luo, Li Yu, Pengzhou Li, Lei Sun","doi":"10.1115/PVP2018-85017","DOIUrl":"https://doi.org/10.1115/PVP2018-85017","url":null,"abstract":"The coolant inside the supercritical water cooled pressure tube operates beyond the critical thermodynamics point of water, and the structure integrity of the pressure tube is of great important to the safety of reactor. Under the accident load, the difference in temperature along the pressure tube wall will cause relatively large thermal stress. Due to the generated high tensile stress, coupled with the internal high pressure load, the defects in the inner surface of the pressure tube may propagate rapidly and even through the wall thickness. This paper investigates the structure integrity of the supercritical water cooled pressure tube based on the deterministic and the probabilistic method of fracture mechanics, and obtains the stress intensity factor and the probabilistic function. It is found that the integrity of the supercritical pressure tube can be maintained from the fracture mechanics analysis under the accident load.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133310876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Presentation of DEFI-PROSAFE Project: Probabilistic Methodology to Assess Margin in Deterministic RPV Integrity Assessment and Proposed Benchmark","authors":"Ralf Tiete, R. Trewin, Sébastien Blasset, Vladislav Pištora, M. Posta, M. Niffenegger, G. Qian","doi":"10.1115/PVP2018-84615","DOIUrl":"https://doi.org/10.1115/PVP2018-84615","url":null,"abstract":"In this paper the project DEFI-PROSAFE is presented.\u0000 In the frame of Nugenia+ project, a work package was dedicated to the “DEFInition of reference case studies for harmonized PRObabilistic evaluation of SAFEty margins in integrity assessment for long-term operation of reactor pressure vessel” (acronym DEFI-PROSAFE). A methodology is proposed to assess safety margins in RPV integrity accounting for uncertainties propagation, because no commonly accepted European approach exists for probabilistic assessment of RPV fast fracture risk.\u0000 The DEFI-PROSAFE methodology, which is based on the comparison between deterministic and probabilistic assessment, will be detailed. The experience gained from the US Screening Criteria (NUREG-1806) and past projects (ICAS, PROSIR), and guideline (IAEA TecDoc 1627) as well as aspects specific to European deterministic integrity approach have been considered. Usually for probabilistic fracture assessment of the RPV, the parameters (describing flaws, material and neutron fluence) are sampled and the RPV cylindrical region is assessed using deterministic thermal hydraulic loading for evaluation of initiation or failure conditional probability. Within DEFI-PROSAFE methodology the uncertainties in thermal-hydraulic input parameters are taken into account and their propagation in the structural assessment is considered. Comparison of RELAP5 thermal hydraulic results and mixing calculation results (KWU-MIX) with experiment relevant to PTS assessment was performed. Furthermore the DEFI-PROSAFE methodology considers RPV discontinuity regions (like RPV nozzle) and specific PIRT analysis has been performed for selection of the TH-parameters.\u0000 A new benchmark for probabilistic assessment of RPV was defined within the DEFI-PROSAFE project. The benchmark definition and case studies based on previous R&D project (ICAS, PROSIR) will be presented. The performance of the new benchmark may be submitted as new European project.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125858726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of the Material Properties and Performance of Hot Isostatically Pressed (HIP) Type 316L Stainless Steel Powders and HIP Processing Available From Today’s International Supply Chain","authors":"W. Kyffin, D. Gandy, Barry Burdett","doi":"10.1115/PVP2018-84072","DOIUrl":"https://doi.org/10.1115/PVP2018-84072","url":null,"abstract":"Hot Isostatic Pressing (HIP) of type 316L austenitic stainless steel powder has been an established manufacturing practice for more than twenty five years within the oil and gas sectors and more recently in the naval defence industry. The successful ASME Code Case approval (N-834) has facilitated the manufacture of 316L components via Powder Metallurgy HIP (PM/HIP) for the civil nuclear sector. However, a number of issues have tended to hinder the uptake of PM/HIP as an alternative viable manufacturing route for both castings and forgings.\u0000 Firstly, the powder specification for 316L and HIP processing parameters has typically been left to the discretion of the manufacturers. As such, the finer details of HIP product specification require greater clarity and definition for optimum performance/reproducibility. Secondly, comparison of historical data for 316L PM/HIP has shown variation in the Charpy impact toughness performance. These differences have been attributed to the oxygen content of the atomised powder, with greater oxygen contents yielding product with reduced impact properties.\u0000 Based on these factors, a systematic study of the current state of the art of 316L commercial powder production, encapsulation/consolidation and selected HIP parameters was undertaken in collaboration with the Electric Power Research Institute (EPRI). A 316L powder specification was developed that primarily limited the oxygen content of the powder to under 130ppm. This lower oxygen limit reflects the improvements that commercial powder suppliers have been making over the past decade to ensure greater powder cleanliness.\u0000 The test programme generated a significant body of test data based on 3 × 3 × 3 matrix of: powder supply, HIP service provider and HIP sustain times. The results were excellent across the full range of variables studied with all test billets passing the specification requirements of ASTM A988 and additional imposed requirements.\u0000 Very consistent 316L material properties were produced for billets manufactured via differing HIP service providers across the comprehensive destructive test programme. This demonstrates the robustness and uniformity of the PM/HIP supply chain in producing 316L material of the requisite quality. In addition, no significant difference in material properties was noted for material pressed between 2–8 hours hold time, suggesting that the HIP process window is large with respect to hold time.\u0000 Of significant note was that material produced with one powder yielded material with consistently the highest strengths and Charpy impact toughness. This has been attributed to chemical composition of the powder, which featured both a low oxygen and also a high nitrogen content.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125469102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flamanville EPR RPV’s Heads Carbon Segregation: Tests Program Definition to Characterize the Mechanical Properties of the Carbon Segregation","authors":"S. Marie, Jérôme Demarecaux, P. Fichot, E. Keim, J. May, M. Lambrecht, R. Chaouadi, P. Birkett, M. Hajjaj, C. Miller","doi":"10.1115/PVP2018-84329","DOIUrl":"https://doi.org/10.1115/PVP2018-84329","url":null,"abstract":"To characterize the mechanical properties of the residual carbon segregation of the Flamanville EPR RPV heads, a testing program have been organized by Framatome and performed in 3 laboratories (Wood, Framatome technical center of Erlangen and SCK Mol).\u0000 This paper presents the tests program, how it has been defined and its goals. The main issue was the impact of the carbon content on the toughness properties. A procedure was defined to characterize specifically the toughness distribution in the upper part of the brittle-to-ductile transition. The ductile regime was also investigated. These tests were completed with tensile, Charpy and drop weight tests, representing a final total of approximatively 1700 mechanical tests.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130367146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fracture Toughness Behaviour of 316L Stainless Steel Samples Manufactured Through Selective Laser Melting","authors":"C. Davies, R. Zhou, Olivia Withnell, Richard A. Williams, T. Ronneberg, P. Hooper","doi":"10.1115/PVP2018-84393","DOIUrl":"https://doi.org/10.1115/PVP2018-84393","url":null,"abstract":"Selective laser melting (SLM) is a relatively new manufacturing technique which offers many benefits. However the utilisation of SLM manufactured components depends on the assurance of their integrity during operation. Fracture toughness testing (JIC) has been performed on as-built compact tension fracture mechanics samples manufactured in three orthogonal directions. When the crack growth plane was transverse to the interface of the build layers, the fracture toughness values were found to be similar to those manufactured using conventional techniques. However, the fracture toughness is significantly reduced when the crack plane is parallel to the interface of the build layers. Simple heat treatments have been performed on Charpy fracture samples and the resulting impact energy values indicate that the fracture toughness of a component may be improved by heat treatment.","PeriodicalId":428760,"journal":{"name":"Volume 6A: Materials and Fabrication","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126244744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}