ATLAS PLUS: Design of Large Scale Fracture Mechanics Tests on a Ferritic Pipe

2018 ◽  
Author(s):  
Tomas Nicak ◽  
Tobias Bolinder ◽  
Elisabeth Keim ◽  
Alexander Eriksson ◽  
Patrick Le Delliou ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Large Scale ◽  
Crack Tip ◽  
Bending Test ◽  
Test Facility ◽  
Small Scale ◽  
Integrity Assessment ◽  
Design Calculations ◽  
Crack Tip Constraint ◽  
Large Scale Tests

This paper summarizes the design calculations performed by Framatome, EDF, KIWA INSPECTA and VTT for three large scale tests on ferritic pipes made of material WB 36 (15 NiCuMoNb 5). The large scale tests will be performed on a 4-point bending test facility provided by EDF under displacement control at room temperature. The overall goal of the planned large scale tests is to demonstrate the effect of the crack tip constraint on the fracture toughness at the component level. Results of those tests will be utilized to develop and validate advanced tools for structural integrity assessment within WP 3 particularly with respect to the transferability of material properties from small scale specimens to large scale components as well as for the development and validation of a procedure for the determination of component fracture resistance curves. Three configurations of the initial defect with different constraint conditions (one through-wall and two surface cracks) are considered. The design calculations are divided into two parts. In the first part an optimization of three different crack shapes is performed on basis of the standard fracture mechanics approach (based on J-Integral) without consideration of the constraint effect. In the second part a quantification of the crack tip constraint for the selected crack configurations from part I is performed. The effect of the constraint on the crack initiation and propagation for the selected crack configurations shall be assessed and compared between each other. Based on these calculations the final flaw configuration for each large scale experiment is selected.

The Experimental Work in Support to ATLAS+ Project

2018 ◽  
Author(s):  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Anna Dahl ◽  
Yann Kayser ◽  
Szabolcs Szavai ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Experimental Work ◽  
Large Scale ◽  
Nuclear Reactor ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Ductile Material ◽  
Small Scale ◽  
Term Operation ◽  
Integrity Assessment

The 4-years European project ATLAS+ project was launched in June 2017. Its main objective is to develop advanced structural assessment tools to address the remaining technology gaps for the safe and long term operation of nuclear reactor pressure coolant boundary systems. The transferability of ductile material properties from small scale fracture mechanics specimens to large scale components is one of the topics of the project. A large programme of experimental work is to be conducted in support of the development and validation of advanced tools for structural integrity assessment within the framework of the work-package 1 (WP 1): Design and execution of simulation oriented experiments to validate models at different scales. The experimental work is based on a full set of fracture mechanics experiments conducted on standard specimens and large scale components (several pipes and one mock-up), including a full materials characterization. Three materials are considered: • a ferritic steel 15NiCuMoNb5 (WB 36) • an aged austenitic stainless steel weld • a VVER (eastern PWR) dissimilar metal weld (DMW) The paper presents the WP 1, the experimental programme and summarizes the first results.

scholarly journals European Project ATLAS+: Small and Large Scale Ductile Tearing Experiments on Ferritic Steel WB36 to Study Transferability of Material Ductile Properties

2019 ◽  
Author(s):  
Anna Dahl ◽  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Willy Vincent
Keyword(s):  
Ferritic Steel ◽  
Large Scale ◽  
Structural Integrity ◽  
Assessment Tools ◽  
Test Facility ◽  
Small Scale ◽  
Feed Water ◽  
Ductile Tearing ◽  
Integrity Assessment ◽  
European Project

Abstract The 4-years European project ATLAS+ (Advanced Structural Integrity Assessment Tools for Safe long Term Operation) has been launched in June 2017. One of its objectives is to study the transferability of material ductile properties from small scale specimens to large scale components and validate some advanced tools for structural integrity assessment. The study of properties transferability is based on a wide experimental programme which includes a full set of fracture experiments conducted on conventional fracture specimens and large scale components (mainly pipes). Three materials are considered in the programme : a ferritic steel WB36 typical from secondary feed water line in German PWR reactors, an aged stainless steel austenitic weld representative of EPR design and a typical VVER austenitic dissimilar weld (DMW). This paper describes the experimental work conducted on the ferritic steel WB 36 (15NiCuMoNb5) and summarizes the experimental results available after 2 years of work. Numerous mechanical tests have been conducted on a wide panel of fracture mechanics specimens for a full characterization of the ferritic steel: Tensile properties, Hardness, Charpy Energy, pre-cracked Charpy PCC, Master curve on CT and SENT specimens, ductile tearing properties on CT and SENT specimens. In parallel, it is planned to test three 4PB large scale tests on pipings (FP1, FP2 and FP3) at room temperature on the EDF test facility with 3 configurations (shape, size and location) of cracks: through wall crack (TWC), internal and external ½ elliptical cracks. Progress of these large scale experiments is described including first results.

Constraint Quantification of Single Edge Notched Bend Specimens Under Large-Scale Yielding

2003 ◽  
Author(s):  
Yuh J. Chao ◽  
Xian-Kui Zhu ◽  
Yil Kim ◽  
M. J. Pechersky ◽  
M. J. Morgan ◽  
...  
Keyword(s):  
Large Scale ◽  
Crack Tip ◽  
Bending Moment ◽  
Additional Term ◽  
Small Scale ◽  
Bending Stress ◽  
Single Edge ◽  
Crack Tip Fields ◽  
Scale Yielding ◽  
Crack Tip Constraint

Because crack-tip fields of single edge notched bend (SENB) specimens are significantly affected by the global bending moment under the conditions of large-scale yielding (LSY), the classical crack tip asymptotic solutions fail to describe the crack-tip fields within the crack tip region prone to ductile fracture. As a result, existing theories do not quantify correctly the crack-tip constraint in such specimens under LSY conditions. To solve this problem, the J-A2 three-term solution is modified in this paper by introducing an additional term derived from the global bending moment in the SENB specimens. The J-integral represents the intensity of applied loading, A2 describes the crack-tip constraint level, and the additional term characterizes the effect of the global bending moment on the crack-tip fields of the SENB specimens. The global bending stress is derived from the strength theory of materials, and proportional to the applied bending moment and the inverse of the ligament size. Results show that the global bending stress near the crack tip of SENB specimens is very small compared to the J-A2 three-term solution under small-scale yielding (SSY), but becomes significant under the conditions of LSY or fully plastic deformation. The modified J-A2 solutions match well with the finite element results for the SENB specimens at all deformation levels ranging from SSY to LSY, and therefore can effectively model the effect of the global bending stress on the crack-tip fields. Consequently, the crack-tip constraint of such bending specimens can now be quantified correctly.

A Fracture Mechanics Based Approach to the Assessment of Seismic Resisting Steel Structures

2006 ◽  
Vol 312 ◽  
pp. 89-94 ◽  
Author(s):  
Clark Hyland ◽  
W. George Ferguson
Keyword(s):  
Stress Intensity ◽  
Fracture Mechanics ◽  
Crack Initiation ◽  
Large Scale ◽  
Crack Tip ◽  
Steel Structures ◽  
Constructional Steel ◽  
Small Scale ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement

A method for assessing likelihood of brittle fracture in cyclically loaded steel assemblies subjected to inelastic strains is proposed. The method proposed is based upon relationships between monotonic and cyclic endurance of steel specimens proposed by Kuwamura and Takagi, and analysis of crack tip opening displacement (CTOD), Charpy V-Notch (CVN) and tensile results of pre-strained, fatigue pre-cracked and side-grooved specimens of constructional steel. The proposed method allows the influence of displacement ductility classification (as used in seismic design of structures), notch geometry, and cyclic strain amplitude history on crack initiation to be incorporated into a single design analysis approach. Small scale CTOD testing of steel materials with various levels of pre-strain may be used to identify stress intensity and crack tip displacement at crack initiation for use in the analysis. The integration of a fracture mechanics based approach to analysing stress intensity in conjunction with assembly plastic deformation characteristics derived from finite element modeling offers the promise of an improved approach to steel assembly design for cyclic plastic endurance and should result in more reliable structures and reduced need for large scale testing. This has particular relevance to the structural design of seismic resisting steelwork assemblies which are expected to develop dependable ductile behaviour under high strain variable amplitude cyclic actions.

STYLE: Mock-Up3 Design—FE Simulation of Crack Growth in a Cladded Ferritic Pipe

2010 ◽  
Author(s):  
Tomas Nicak ◽  
Herbert Schendzielorz ◽  
Elisabeth Keim ◽  
Gottfried Meier ◽  
Dominique Moinereau ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Crack Growth ◽  
Large Scale ◽  
Assessment Tools ◽  
Bending Test ◽  
Test Facility ◽  
J Integral ◽  
Material Data ◽  
Porous Plasticity ◽  
Micromechanical Models

This paper describes numerical analyses performed in connection with the design of a large scale mock-up test planned within the European project on structural integrity STYLE. There are three large scale mock-up tests planned in STYLE, each of them dedicated to investigate specific effects. Mock-up3 (cladded ferritic pipe with an outer diameter of 420 mm) is foreseen to investigate transferability of material data, including fracture mechanics properties. Usually, material data are obtained by testing small specimens, which are subsequently used for the assessment of large scale structures (real components). The Mock-Up3 is an original part of a surge line made of low alloy steel 20MnMoNi55 (similar to SA 508 Grade 3, Cl. 1). The test will be performed on a 4 point bending test facility provided by EDF under displacement control at room temperature. The goal of the test is to obtain the stable crack growth of an inner surface flaw until a break through the wall occurs. The range of assessment tools applied within STYLE includes assessment of component failure by fracture mechanics analyses using methods based on fracture mechanics parameters (e.g K1 or J-Integral) as well as methods based on local micromechanical models (e.g. Gurson’s porous plasticity model and its variations). Micromechanical models have some advantages compared to those based on single term fracture parameters, especially if one considers designing a large scale mock-up test. The precise description of the entire damage process, beginning from with initiation on brittle particles, their growth leading to the crack initiation and finally to the macroscopic crack growth, can be seen as the most valuable attribute of these methods. Such methods make it possible to perform a set virtual tests prior to the real one, on which different test conditions can be investigated. A comparison of the common assessment method based on J-Integral with a local approach method, based on the Gurson’s porous plasticity theory, will be presented in this paper. Details on the Gurson model calibration will also be provided. Moreover, influence of boundary conditions on the large scale test will be discussed.

Comparison of Strip Yield and Net Section Plasticity Models for a Bar in Bending With a Single Edge Crack

2017 ◽  
Author(s):  
Wolf Reinhardt ◽  
Don Metzger
Keyword(s):  
Edge Crack ◽  
Large Scale ◽  
Stress Singularity ◽  
Crack Tip ◽  
Small Scale ◽  
Single Edge ◽  
Yield Model ◽  
Strip Yield Model ◽  
Crack Tip Plasticity ◽  
Stress And Deformation

The strip yield model is widely used to describe crack tip plasticity in front of a crack. In the strip yield model the stress in the plastic zone is considered as known, and stress and deformation fields can be obtained from elastic solutions using the condition that the crack tip stress singularity vanishes. The strip yield model is generally regarded to be valid to describe small scale plasticity at a crack tip. The present paper examines the behavior of the strip yield model at the transition to large-scale plasticity and its relationship to net section plasticity descriptions. A bar in bending with a single edge crack is used as an illustrative example to derive solutions and compare with one-sided and two-sided plasticity solutions.

scholarly journals LARGE AND SMALL SCALE WAVE OVERTOPPING MEASUREMENTS FOR AFSLUITDIJK REHABILITATION PROJECT

2020 ◽  
pp. 15
Author(s):  
Wouter Ockeloen ◽  
Coen Kuiper ◽  
Sjoerd van den Steen
Keyword(s):  
Water Management ◽  
Physical Model ◽  
Large Scale ◽  
Wadden Sea ◽  
Model Tests ◽  
Small Scale ◽  
Water Safety ◽  
Wave Overtopping ◽  
Physical Model Tests ◽  
Large Scale Tests

The 'Afsluitdijk' is a 32 km enclosure dam which separates the Wadden sea and the Lake IJssel. The dam currently undergoes a major rehabilitation to meet the requirements with regard to water safety. The Dutch Ministry of infrastructure and Water Management (Rijkswaterstaat division) has commissioned Levvel, a consortium of BAM, Van Oord and Rebel, to prepare the design and carry out the reconstruction of the dam including sluices and highway. The project includes reinforcement of the armour layers and wave overtopping reduction. As part of the contract Rijkswaterstaat prescribed the contractor (Levvel) to verify the design with large scale physical model tests (min. 1:3 scale). These tests were carried out in the Delta Flume of Deltares. Prior to the large scale tests, smaller scale tests (1:20) have been carried out to optimize the design with regard to armour stability and wave overtopping. The research described here focuses on the wave overtopping.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kPga0wVCCIE

scholarly journals Long Term and Large-Scale Continuous Studies on Zinc(II) Sorption and Desorption on Hybrid Pectin-Guar Gum Biosorbent

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 96 ◽  
Author(s):  
Agata Jakóbik-Kolon ◽  
Joanna Bok-Badura ◽  
Andrzej Milewski ◽  
Krzysztof Karoń
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Guar Gum ◽  
Mechanical Stability ◽  
Small Scale ◽  
Time Model ◽  
Fine Grain ◽  
Real Wastewater ◽  
Scale Experiment ◽  
Large Scale Tests

Pectin-guar gum biosorbent was tested for zinc(II) ions removal in column process. Sorption–desorption experiments were performed in laboratory and at larger scale. The breakthrough and elution curves were obtained for various conditions. The Bed Depth Service Time model was tested for utility in data estimation. Possibility of sorbent reuse and its lifetime was examined in 20 repeated sorption–desorption cycles. Finally, tests were repeated for real wastewater from galvanizing plant, giving satisfactory results. The effectiveness of Zn(II) sorption happened to be dependent on process parameters; tests have proved that it increased with increasing bed height and with decreasing flow rate or grain size. For an initial zinc concentration of 30 mg/L, even 2096 mL of zinc solution could be purified in small scale experiment (2 g of fine grain sorbent and flow rate 60 mL/h) or 5900 L in large-scale (16 kg of large grain sorbent and flow rate 45 L/h). This allowed for 40-fold or 49-fold zinc increases in concentration in one sorption–desorption cycle. The most successful results are meant that at least 20 sorption–desorption cycles could be performed on one portion of biosorbent without loss of its effectiveness, large-scale tests for real wastewater from galvanizing plant gave satisfactory results, and that the form and mechanical stability of our sorbent is suitable for column usage with flow rates applicable in industry.

STYLE: Study on Transferability of Fracture Material Properties From Small Scale Specimens to a Real Component

2011 ◽  
Author(s):  
Tomas Nicak ◽  
Herbert Schendzielorz ◽  
Elisabeth Keim ◽  
Gottfried Meier
Keyword(s):  
Fracture Mechanics ◽  
Material Properties ◽  
Large Scale ◽  
Fracture Behaviour ◽  
Experimental Investigations ◽  
Small Scale ◽  
Real Component ◽  
Material Data ◽  
Analytical Work ◽  
Constraint Effects

This paper describes numerical and experimental investigations on transferability of material properties obtained by testing of small scale specimens to a real component. The presented study is related to the experimental and analytical work performed on Mock-up3, which is one of three unique large scale Mock-ups tested within the European project STYLE. Mock-up3 is foreseen to investigate transferability of material data, in particular fracture mechanics properties. An important part of this work is to study constraint effects on different small scale specimens and to compare their fracture behaviour with the fracture behaviour of a large scale (component like) structure. The Mock-Up3 is an original part of a surge line made of low alloy steel 20 MnMoNi 5 5 (which corresponds to SA 508 Grade 3, Cl. 1). The goal of the test is to introduce stable crack growth of an inner surface flaw until a break through the wall occurs. To design such a test reliable fracture mechanics material properties must be available. Usually, these material data are obtained by testing small specimens, which are subsequently used for the assessment of a large scale structure (component). This is being done under the assumption that these “small scale” material properties are fully transferable to “large scale” components. It is assumed that crack initiation in the ductile tearing regime is rather independent of the crack shape, a/W ratio, loading condition or size of the specimen (constraint effects). In order to check the aforementioned assumption and to improve understanding of the physical process leading to failure of cracked components comprehensive experimental and analytical work is being undertaken in STYLE. This paper summarizes Up-To-Date available results, which have been achieved during the first 15 months of the project.

Solar Upgrading of Fuels for Generation of Electricity

2001 ◽  
Vol 123 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Rainer Tamme ◽  
Reiner Buck ◽  
Michael Epstein ◽  
Uriyel Fisher ◽  
Chemi Sugarmen
Keyword(s):  
Gas Turbines ◽  
Large Scale ◽  
Fossil Fuels ◽  
High Efficiency ◽  
Combined Cycle ◽  
Test Facility ◽  
Small Scale ◽  
Start Up ◽  
Efficiency Conversion ◽  
Solar Field

This paper presents a novel process comprising solar upgrading of hydrocarbons by steam reforming in solar specific receiver-reactors and utilizing the upgraded, hydrogen-rich fuel in high efficiency conversion systems, such as gas turbines or fuel cells. In comparison to conventionally heated processes about 30% of fuel can be saved with respect to the same specific output. Such processes can be used in small scale as a stand-alone system for off-grid markets as well as in large scale to be operated in connection with conventional combined-cycle plants. The complete reforming process will be demonstrated in the SOLASYS project, supported by the European Commission in the JOULE/THERMIE framework. The project has been started in June 1998. The SOLASYS plant is designed for 300 kWel output, it consists of the solar field, the solar reformer and a gas turbine, adjusted to operate with the reformed gas. The SOLASYS plant will be operated at the experimental solar test facility of the Weizmann Institute of Science in Israel. Start-up of the pilot plant is scheduled in April 2001. The midterm goal is to replace fossil fuels by renewable or non-conventional feedstock in order to increase the share of renewable energy and to establish processes with only minor or no CO2 emission. Examples might be upgrading of bio-gas from municipal solid waste as well as upgrading of weak gas resources.

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