Mechanical Behaviour of a Forged Ferritic Steel Shell Containing Numerous Hydrogen Flakes

2018 ◽  
Author(s):  
C. Jacquemoud ◽  
I. Delvallée-Nunio
Keyword(s):  
Steam Generator ◽  
Large Scale ◽  
Base Material ◽  
Scientific Basis ◽  
Pressure Vessels ◽  
Steel Shell ◽  
Test Results ◽  
Transition Range ◽  
Fem Simulations ◽  
Fatigue Precrack

Following the flaw indications found in summer 2012 in two Belgian Reactors Pressure Vessels (RPV), WENRA recommended [1] the nuclear safety authorities in Europe to verify the material quality and integrity of the RPV in a 2-step approach: 1) a comprehensive review of the manufacturing and inspection records of the forgings of the RPV, 2) an additional UT examination of the base material of the vessels if needed. In this context, and to consolidate scientific basis on this issue, IRSN, the French technical safety organization, conducted, with CEA support, a test program aiming at studying the consequences of hydrogen flakes in large forgings of primary equipment (RPV, steam generator, pressurizer). Framatome provided the material to be investigated, namely two blocks of a steam generator vessel shell in 18MND5 steel: a block without flake — the reference block — and a block including a high density of hydrogen flakes. This shell — so called VB395 — was rejected because of an incident which occurred during the degassing heat treatment. Fracture toughness has been evaluated from 85 tests in the ductile range and the ductile-to-brittle transition range of the material. The test results on usual 0.5T-CT specimens were compared to those on specimens containing a hydrogen flake replacing the fatigue precrack. The latter were interpreted using 3D elastic-plastic X-FEM simulations allowing the modelling of the irregular flake geometry. Furthermore, large scale bending specimens with multiple flakes have been tested at −100°C. These tests were interpreted thanks to 3D X-FEM simulations allowing the analysis of the hydrogen flake interaction in terms of KJ.

Laboratory Study of Hydraulic Conductivity for Coarse Aggregate Bases

1996 ◽  
Vol 1519 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Brian W. Randolph ◽  
Jiangeng Cai ◽  
Andrew G. Heydinger ◽  
Jiwan D. Gupta
Keyword(s):  
Hydraulic Conductivity ◽  
Large Scale ◽  
Base Material ◽  
Testing Procedure ◽  
Test Methods ◽  
Standard Test ◽  
Coarse Grained ◽  
Test Results ◽  
Wide Range ◽  
Pavement Structures

Inadequate drainage of pavement structures has been identified as a primary cause of pavement distress. Hydraulic conductivity is the most important factor controlling drainage capability. Coarse grained materials have high values of hydraulic conductivity. ASTM and AASHTO standard test methods are limited for coarse materials used in pavement bases and subbases because of their high permeability and large particle sizes and the horizontal flow in the field conditions. A large scale horizontal permeameter and a testing procedure were developed and the range of hydraulic conductivities of six base and subbase specifications made up of three material types provided by the Ohio Department of Transportation were evaluated. A horizontal permeameter (305 × 305 × 457 mm) and a testing procedure were developed to reduce errors produced by sidewall leakage, partial saturation, measurement of small head differences, and interpretation of turbulent flow as laminar flow. Fifty-four samples were tested, including various gradations of nonstabilized, portland cement stabilized, and asphalt stabilized bases made of limestone, gravel, or slag materials. The results obtained were analyzed and compared with previous research, empirical relations, and field test results of similar base and subbase materials. The comparisons and analyses indicate that the permeameter and the procedure produce representative results. Test results indicate a wide range of hydraulic conductivities for gradations at each extreme of a specification. Effective porosities were also found to be as low as 6 percent for the fine gradation of a common limestone base material.

Experimental Verification of the Behavior of Underclad Cracks Using Semi-Large Scale Specimens

2008 ◽  
Author(s):  
Vladislav Pisˇtora ◽  
Milan Brumovsky´ ◽  
Dana Lauerova´
Keyword(s):  
Large Scale ◽  
Failure Process ◽  
Base Material ◽  
Pressure Vessels ◽  
Aged Material ◽  
Ductile Tearing ◽  
Four Point Bending ◽  
Final Failure ◽  
Embedded Crack

During years 2005–2006 a series of semi-large scale experiments of specimens containing underclad (embedded) crack were performed in NRI Rez. The experiments were performed within EU PHARE project in cooperation with VTT, FNS, TVONS (Finland) and Tecnatom (Spain). The aim of the project was to investigate fracture mechanics properties of cladding in particular to establish the role of cladding in fracture failure process of the specimens, and to exploit the obtained knowledge in the procedure for evaluation of integrity of WWER reactor pressure vessels. The specimens were manufactured from an artificially aged material of decommissioned (not operated) RPV of WWER-440 type. Each of specimens contained through-thickness crack embedded in the base material and was loaded by four-point-bending (4PB) loading. During loading, majority of specimens exhibited pop-ins followed by ductile tearing of cladding and final failure. Evaluation of the experiments concentrated on both process of cleavage fracture in base material and process of ductile tearing in cladding. In the presented paper, the results of experiments are described in detail. New proposal for procedure of assessment of RPV integrity, based on the PHARE project, was prepared and will be presented in a separate paper.

scholarly journals Semi-Large Scale Experiments Performed on Specimens With Underclad Cracks

2008 ◽  
Author(s):  
Vladislav Pistora ◽  
Milan Brumovsky
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Failure Process ◽  
Base Material ◽  
Video Camera ◽  
Pressure Vessels ◽  
Ductile Tearing ◽  
Four Point Bending ◽  
High Speed Video Camera ◽  
Reactor Pressure

During years 2005–2006, a series of semi-large scale experiments on specimens containing underclad (embedded) crack were performed in NRI Rez. The experiments were performed within EU PHARE project EUROPAID/116529/D/SV/CZ, in cooperation with VTT, FNS, TVONS (Finland) and Tecnatom (Spain). The aim of the project was to investigate fracture mechanics properties of cladding, in particular, to establish the role of cladding in the fracture/failure process of the specimen, and based on obtained results to improve the current procedure for evaluation of integrity of WWER reactor pressure vessels. The specimens were manufactured from artificially aged material of decommissioned (not operated) reactor pressure vessel of WWER 440 Type NPP. Each of the specimens contained through-thickness crack embedded in the base material (with approx. 3 mm ligament separating the upper crack front from cladding), and was loaded by four-point-bending loading at room temperature. During loading, majority of specimens exhibited pop-ins followed by ductile tearing of cladding and final failure; only 3 specimens fractured through suddenly, without preceding pop-ins. Evaluation of the experiments concentrated on both process of cleavage fracture in base material and process of ductile tearing in cladding. In the presented paper, the results of experiments are in detail described, including photos from the experiments and photos taken with using high-speed video camera during some of experiments.

Using Indicator Bacteria and Salmonella Test Results from Three Large-Scale Beef Abattoirs over an 18-Month Period To Evaluate Intervention System Efficacy and Plan Carcass Testing for Salmonella

2007 ◽  
Vol 70 (12) ◽  
pp. 2732-2740 ◽  
Author(s):  
JOHN R. RUBY ◽  
JUN ZHU ◽  
STEVEN C. INGHAM
Keyword(s):  
Lactic Acid ◽  
Large Scale ◽  
Microbial Contamination ◽  
Test Results ◽  
Microbiological Contamination ◽  
Negative Results ◽  
Intervention Process ◽  
Beef Carcasses ◽  
Causative Factors ◽  
Plate Counts

To develop a process for predicting the likelihood of Salmonella contamination on beef carcasses, we evaluated the influence of several possible causative factors (i.e., year, abattoir, day of week, month, and intervention system components) on the risk of Salmonella and indicator organism contamination. Hide and carcass sponge samples were collected in 2005 to 2006 in six steps at three abattoirs in the East (A), Midwest (B), and Southwest (C) United States. Each abattoir used the same intervention system. Samples were analyzed for aerobic plate counts (APCs; n = 18,990) and Enterobacteriaceae counts (EBCs; n = 18,989) and the presence or absence of Salmonella (n = 5,355). Our results demonstrated that many factors play a significant role in the level of microbial contamination of beef carcasses. Overall, Salmonella prevalence and EBC levels were significantly higher in 2006 than in 2005. APCs and EBCs were highest in abattoirs A (3.57 log CFU/100 cm2) and B (1.31 log CFU/100 cm2). The odds of detecting a positive Salmonella isolate were greatest in abattoir C and lowest in abattoir A. Across the three abattoirs, the overall intervention process effectively reduced microbiological contamination. Salmonella prevalence fell from 45% (preevisceration) to 0.47% (postchilled–lactic acid), and there were APC and EBC reductions of 5.43 and 5.28 log CFU/100 cm2, respectively, from hide-on to postchilled–lactic acid samples. At each abattoir, composites of three individual EBC-negative carcass samples yielded Salmonella-negative results 97 to 99% of the time. These results suggest the possibility of using indicator test results to accurately predict the absence of Salmonella in a beef carcass sample.

High Frequency Vibration Analysis of Automotive Body Panels with Damping Materials

2010 ◽  
Vol 36 ◽  
pp. 293-296
Author(s):  
Yoshio Kurosawa ◽  
Takao Yamaguchi
Keyword(s):  
High Frequency ◽  
Large Scale ◽  
The Body ◽  
Viscoelastic Damping ◽  
Fe Model ◽  
Test Results ◽  
Automotive Body ◽  
Modal Damping ◽  
Practical Tool ◽  
Damping Materials

We have developed a technique for estimating vibrations of an automotive body structures with viscoelastic damping materials using large-scale finite element (FE) model, which will enable us to grasp and to reduce high-frequency road noise（200～500Hz）. In the new technique, first order solutions for modal loss factors are derived applying asymptotic method. This method saves calculation time to estimate modal damping as a practical tool in the design stages of the body structures. Frequency responses were calculated using this technique and the results almost agreed with the test results. This technique can show the effect of the viscoelastic damping materials on the automotive body panels, and it enables the more efficient layout of the viscoelastic damping materials. Further, we clarified damping properties of the automotive body structures under coupled vibration between frames and panels with the viscoelastic damping materials.

scholarly journals Ice-Accretion Test Results for Three Large-Scale Swept-Wing Models in the NASA Icing Research Tunnel

2016 ◽  
Author(s):  
Andy P. Broeren ◽  
Mark G. Potapczuk ◽  
Sam Lee ◽  
Adam M. Malone ◽  
Bernard P. Paul ◽  
...  
Keyword(s):  
Large Scale ◽  
Ice Accretion ◽  
Test Results ◽  
Swept Wing

Analytical Model for Rockfall Protection Galleries - a Blind Prediction of Test Results and Conclusion

2011 ◽  
Vol 82 ◽  
pp. 722-727 ◽  
Author(s):  
Kristian Schellenberg ◽  
Norimitsu Kishi ◽  
Hisashi Kon-No
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Test Results ◽  
Blind Prediction ◽  
Proposed Model ◽  
Input Parameters ◽  
Scale Test ◽  
Definition Of ◽  
Protective Structures ◽  
Cushion Layer

A system of multiple degrees of freedom composed out of three masses and three springs has been presented in 2008 for analyzing rockfall impacts on protective structures covered by a cushion layer. The model has then been used for a blind prediction of a large-scale test carried out in Sapporo, Japan, in November 2009. The test results showed substantial deviations from the blind predictions, which led to a deeper evaluation of the model input parameters showing a significant influence of the modeling properties for the cushion layer on the overall results. The cushion properties include also assumptions for the loading geometry and the definition of the parameters can be challenging. This paper introduces the test setup and the selected parameters in the proposed model for the blind prediction. After comparison with the test results, adjustments in the input parameters in order to match the test results have been evaluated. Conclusions for the application of the model as well as for further model improvements are drawn.

Design and Testing of ITER TF Coil Insulations

2011 ◽  
Vol 21 (3) ◽  
pp. 3127-3131 ◽  
Author(s):  
Matthew W. Hooker ◽  
Jennifer K. Walsh ◽  
Mark W. Haynes ◽  
Naseem A. Munshi
Keyword(s):  
Radiation Exposure ◽  
Large Scale ◽  
Mechanical Performance ◽  
International Organization ◽  
Vacuum Impregnation ◽  
Test Results ◽  
Qualification Test ◽  
Insulation System ◽  
Cyanate Ester Resin ◽  
Design And Testing

The design of the ITER Toroidal Field (TF) coils requires an insulation system that is amenable to the very large scale vacuum impregnation processes planned for the construction of these devices, and that will provide reliable electro-mechanical performance after radiation exposure. To address this need, CTD has developed an epoxy/cyanate ester resin system designated CTD-425. This material meets the processing requirements for use in the TF coils, and cyclic mechanical testing of conductor assemblies has demonstrated its electro-mechanical strength after 60,000 mechanical cycles. In addition, this product recently passed radiation exposure tests coordinated by the ITER International Organization and is now qualified for use in constructing the TF coils. This paper summarizes the performance characterization and qualification test results for this insulation.

Oxygen Pressure Aging. Improved Equipment

1938 ◽  
Vol 11 (4) ◽  
pp. 722-727
Author(s):  
L. M. Freeman
Keyword(s):  
Oxygen Pressure ◽  
Pressure Vessel ◽  
Large Scale ◽  
Oxygen Supply ◽  
Pressure Vessels ◽  
Water Bath ◽  
Aging Test ◽  
Constant Temperature Water Bath ◽  
Temperature Water ◽  
Continuous Source

Abstract Since the introduction of the oxygen pressure-aging test by Bierer and Davis, prevailing standard conditions for the test have been 70° C. (158° F.) and 300 pounds per square inch oxygen pressure. Various types of equipment have been used; usually the equipment has consisted of a pressure vessel immersed in a constant-temperature water bath to which is connected an oxygen supply. In the majority of instances the equipment has been difficult to operate and maintain for several reasons: Immersion of pressure vessels in a water bath made handling difficult. Corrosion was a continuous source of trouble, causing “freezing” of cover bolts and making it difficult to obtain a leakproof oxygen seal between cover and vessel. This caused loss of oxygen. Each time the pressure vessel was removed from the bath it was necessary to disconnect the oxygen supply and make the connection again when the test was started. This also caused loss of oxygen. If more than one pressure vessel was connected to the oxygen supply and a safety released, the entire oxygen supply was exhausted. The original pressure vessels were relatively large. Since the use of age resistors on a large scale, smaller units have been desirable in order to decrease migration of age resistors and eliminate erroneous results. Some of these operation difficulties were outlined by Ingmanson and Kemp, who also emphasized the importance of temperature control to obtain reproducible results. It is the purpose of this paper to describe an improved oxygen pressure installation which avoids some of these difficulties.

The Properties of Welded Joints Made by 6082-T6 Aluminium Alloy and their Behaviour under Cyclic Loading Conditions

2015 ◽  
Vol 812 ◽  
pp. 375-380 ◽  
Author(s):  
D. Pósalaky ◽  
János Lukács
Keyword(s):  
Cyclic Loading ◽  
Automotive Industry ◽  
Welded Joints ◽  
Structural Engineering ◽  
Physical Simulation ◽  
Base Material ◽  
Point Of View ◽  
Test Results ◽  
Structural Elements ◽  
Effective Use

The magnitude of different aluminium alloys, especially the ones with higher strength, are increasing in the structural engineering, not just the usual applications (like the aerospace industry) but more likely in the automotive industry. There are more assumptions of the effective use of aluminium; we should highlight two important factors, the technological and the applicability criterions. The technological criterion is the joining of structural elements, frequently with welding thus the technological criterion ultimately is the weldability. The assumption of applicability comes from the loading capability of these structures, which is typically cyclic loading so the key issue from the point of view of applicability is the resistance to fatigue. This article represents physical simulation and fatigue test results both on the base material and on the welded joints.

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