Calibration of Flaw Extension Model Under Ratcheting Fatigue

2009 ◽  
Author(s):  
Paulo Gioielli ◽  
Jaime Buitrago ◽  
Wan Kan ◽  
Michael Weir ◽  
Graham Chell ◽  
...  
Keyword(s):  
Large Scale ◽  
Fatigue Behavior ◽  
High Growth ◽  
Fatigue Loading ◽  
Small Scale ◽  
Extension Model ◽  
Full Scale Tests ◽  
Welded Pipe ◽  
Large Scale Tests ◽  
Tearing Resistance

Ratcheting fatigue loading arises from the superposition of elastic cyclic loads and monotonically increasing mean strains well into the plastic domain, resulting in simultaneous tearing and fatigue of initial welding flaws. The ratcheting loads may be due to thermal gradients set by startups and shutdowns or by soil uplifts and settlements. Under these conditions, fatigue and fracture phenomena could interact, accelerating the extension of initial fabrication flaws above that predicted to occur by either mechanism acting alone. Evaluation of ratcheting fatigue behavior will impact the weld inspection criteria that ensure pipeline integrity. A previous paper [Gioielli, et al ’08] described a model that evaluates 1) tearing based on applied elastic-plastic driving force (J) versus tearing resistance obtained from standard J-R curve tests and 2) tearing-fatigue based on an extension of Paris law re-expressed in terms of an effective ΔJ instead of ΔK enabling it to be extrapolated to the very high growth rates encountered in the elasto-plastic regime. The model was successfully calibrated to small-scale tests. This paper extends the model calibration to large-scale welded pipe tests subjected to cyclic tensile loads while internally pressurized. To that end, 1) new J solutions were developed for pressurized pipes under load-controlled conditions, and 2) comparisons were made of predicted flaw extensions to those obtained experimentally from full-scale tests. The model predictions using average tensile properties and SENT-based tearing resistance of flaw extensions compared favorably to those measured in the large-scale tests, but additional tests are needed before the model can be used in design.

Evaluation of Welding Flaws Under Ratcheting Fatigue

2008 ◽  
Author(s):  
Paulo Gioielli ◽  
Jaime Buitrago ◽  
Wan Kan ◽  
Michael Weir ◽  
Graham Chell ◽  
...  
Keyword(s):  
Crack Extension ◽  
Large Scale ◽  
Driving Forces ◽  
Fatigue Loading ◽  
Small Scale ◽  
Cyclic Loads ◽  
Mechanics Model ◽  
Plastic Domain ◽  
Large Scale Tests ◽  
Crack Growth Rates

Hydrocarbon-carrying lines can be subjected to cyclic loads superimposed on monotonically increasing mean strains well into the plastic domain, resulting in tearing and tearing fatigue of initial welding flaws. This combined demand is referred to here as ratcheting fatigue. Examples of these loads are frost-heave in pipelines and thermal cycling of flowlines. This paper presents the experimental verification of a fracture mechanics model of monotonic and cyclic crack extension under ratcheting fatigue loads and its calibration to small-scale tests. The model is an extension of one currently used to predict tearing and tear-fatigue due to reeling. Crack driving forces (J-solutions) under load- and displacement-control conditions were derived and used with the model to predict test results. A total of 24 single-edge notched bend (SEN-B) specimens, taken from a welded riser, were tested for crack extension under combined monotonic and cyclic loads. Comparisons of predicted to measured fatigue crack-growth rates, and alternatively cyclic J-R curves, provide quantitative and qualitative validation of the model. However, calibration to large–scale tests are needed before the model can be used for design. ExxonMobil has already completed the first set of large-scale pipe tests under ratcheting fatigue loading, including internal pressure.

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.

INVESTIGATING EXPLOSIVE SENSITIVITY TO ELECTROSTATIC DISCHARGE ACCORDING TO NATO STANDARDIZATION DOCUMENTS

2016 ◽  
pp. 39-60
Author(s):  
Maciej MISZCZAK, ◽  
Cezary Kwiecień ◽  
Sławomir Gryka
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Rocket Propellants ◽  
Smokeless Powders ◽  
Solid Explosives ◽  
Solid Rocket ◽  
Susceptibility Tests ◽  
Explosive Sensitivity ◽  
Solid Rocket Propellants ◽  
Large Scale Tests

Some small scale methods for testing the sensitivity against ESD (Electro Static Discharge) of solid explosives like primary explosives, booster explosives, high explosives, gun and rocket propellants (smokeless powders and solid rocket propellants) and pyrotechnic compositions are overviewed in the paper from the point of NATO standardisation documentation that includes Standard Agreement (STANAG) 4490 [1], Allied Ordnance Publication AOP-7 [2] and STANAG 4170 [3]. The overview is supplemented with analyses and assessments of methods and received results. ESD sensitivity tests of explosives in small scale have not been unified yet in NATO standardization documentation in contradiction to NATO large scale tests. Such unification would be beneficial as it could lead to a greater reliability of results of explosive ESD susceptibility tests performed e.g. in the frame of interlaboratory tests.

Large Scale Tests of Strain Capacity of Pipe Sections With Circumferential Defects Subjected to Installation-Induced Plastic Strain History

2009 ◽  
Author(s):  
Ba˚rd Nyhus ◽  
Erling O̸stby ◽  
Zhiliang Zhang ◽  
Erlend Olso̸ ◽  
Per Arne Ro̸stadsand ◽  
...  
Keyword(s):  
Large Scale ◽  
Base Material ◽  
Bending Moment ◽  
Full Scale ◽  
Strain History ◽  
Strain Capacity ◽  
Four Point Bending ◽  
Full Scale Tests ◽  
Circumferential Defects ◽  
Large Scale Tests

Installation of offshore pipelines by reeling introduces plastic pre-straining. The pre-strain history is not homogenous and it will vary around the circumference of the pipe. The pre-strain history will modify the yield and flow properties. Also, the fracture toughness may be influenced by the pre-straining. The result is that the bending strain capacity of pipelines during operation will differ depending on how the bending moment coincides with pipe orientation during installation. Three full scale tests of 12″ x-60 pipes with wall thickness 19.3mm and a 3×100 mm outer surface defect were performed to investigate the effect of pre-strain history. Two pipes were pre-strained in bending to 2% strain in the outer fibre and then straightened to simulate the reeling. The final tests to establish the strain capacity during operation as a function of strain history were performed in four point bending with an internal pressure of 325 bar. The strain capacity for the side of the pipe that ends in tension and the side that ends in compression from pre-straining was 1.7% and 2.6% respectively. The strain capacity of the third test without pre-straining was 5.7%. The results show that pre-straining will modify the strain capacity and the effect must be taken into account in engineering critical assessment of pipes during operation. The effect of prestraining should be evaluated for all installation methods that involve plastic deformation during installation, and not only reeling. It is important to note that the notch size in the full scale tests was larger than what would normally be accepted for reeling. In addition the notch was positioned in base material and not in weld metal, which is a more realistic position for a notch. The welds are normally overmatched and this might reduce the effect of prestraining.

scholarly journals PENGEMBANGAN KONSTRUK INSTRUMEN HASIL PEMBELAJARAN PRAKTIK KARAWITAN JAWA

2014 ◽  
Vol 18 (2) ◽  
pp. 168-187
Author(s):  
Budi Raharja ◽  
Suminto A. Sayuti
Keyword(s):  
Data Analysis ◽  
Focus Group ◽  
Product Development ◽  
Correlation Coefficient ◽  
Large Scale ◽  
Group Discussion ◽  
Small Scale ◽  
Fitness Test ◽  
Content Factor ◽  
Large Scale Tests

Penelitian ini mengembangkan instrumen hasil pembelajaran praktik karawitan Jawa dari perspektif  keterampilan dan sikap. Perspektif keterampilan menilai kemampuan peserta didik menyelaraskan komponen pembelajaran (melodi, irama/tempo, dan bunyi/nada); sedangkan perspektif sikap menilai pemahaman, penghayatan, dan pengamalan komponen pembelajaran tersebut. Langkah-langkahnya meliputi pengembangan produk, validasi produk, implementasi produk, dan analisis data. Pengembangan produk meliputi pengembangan instrumen keterampilan dan pengembangan instrumen sikap; validasi produk menguji produk dalam diskusi kelompok terfokus, seminar instrumen, dan validasi ahli; implementasi produk adalah mengaplikasikan instrumen dalam uji coba skala kecil dan skala besar serta uji coba utama; sedangkan analisis datanya menggunakan uji kecocokan model. Hasil uji kecocokan model menyatakan bahwa model dinyatakan fit dengan koefisien korelasi antara 0,90 hingga 0,98 dan muatan faktor antara 0,62 hingga 0,91. Instrumen menghasilkan informasi kemampuan menyelaraskan melodi, irama, dan bunyi ricikan serta karakteristik tabuhan peserta didik dari perspektif dan pemahaman, penghayatan, dan pengamalan komponen pembelajarannya. Kata kunci: karawitan, penilaian, keterampilan, sikap _____________________________________________________________ DEVELOPING AN INSTRUMENT CONSTRUCT FOR ASSESSING THE JAVANESE KARAWITAN LEARNING OUTCOMEAbstract This study developed an instrument for assessing learning achievement of Javanese karawitan practice from the perspectives of skill and attitude. The skill perspective evaluates the students’ ability to harmonize the learning components (melody, rhythm/tempo, and sound/tone); while the attitude perspective evaluates their understanding, comprehension, and application of those learning components. The steps in doing the research include product development, product validation, product implementation, and data analysis. Product development includes developing the skill instruments and developing the attitude instruments; while product validation includes testing the product in focus group discussion, seminar for the instruments, and expert judgment. Product implementation is applying the instrument in small-scale and large-scale tests as well as main testing, while the data analysis used model fitness test. The result of model fitness test shows that this model is fit with correlation coefficient from 0.90 to 0.98 and content factor from 0.62 to 0.91. The instrument has yielded information concerning the ability of students to harmonize melody, rhythm, and the ricikan and tabuhan sounds from the perspectives of understanding, comprehending, and applying the learning components.Keywords: karawitan, assessment, skill, and attitude

scholarly journals Developing STEM-based TGT learning model to improve students' process skills

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Faizah Firdaus ◽  
Wachju Subchan ◽  
Erlia Narulita
Keyword(s):  
Research And Development ◽  
21St Century ◽  
Large Scale ◽  
Learning Model ◽  
Small Scale ◽  
Process Skills ◽  
Learning Models ◽  
Science Process Skills ◽  
Team Games ◽  
Large Scale Tests

Strengthening STEM-oriented learning is necessary for 21st century, so the development of appropriate learning models must be carried out. The aimed to of this study were analized validity, effectiveness, and practicality of STEM-based Team Games and Tournament (TGT) learning model towards the students' science process skills. This research was research and development (R&D) with a 4-D development namely; Defining, Designing, Developing, and Disseminating. The study involved 2 experts as validators, 2 teachers as user, and 112 students in small-scale tests, large-scale tests, and distribution tests in SMA. The research was done until the stage of disseminating and produced. The results showed the validity value of 83% was categorized as very valid, the effectiveness score of 83.9% was categorized as good, and the practicality score was 87.5%, so that it was declared valid, effective, and practical to improve the science process skills. Therefore, it is recommended to be applied in schools.

Shear Tests of Composite Slabs, Experimental and Numerical Investigation

2014 ◽  
Vol 923 ◽  
pp. 217-220 ◽  
Author(s):  
Josef Holomek ◽  
Miroslav Bajer ◽  
Jan Barnat ◽  
Martin Vild
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Concrete Slabs ◽  
Shear Tests ◽  
Composite Action ◽  
Permanent Formwork ◽  
Composite Slabs ◽  
New Type ◽  
Large Scale Tests ◽  
Scale Shear

Composite slab is being used for horizontal structures. The sheeting can serve as a permanent formwork and no additional reinforcement can be required. The slabs are then fast and easy assemble construction which can be effectively used in reconstructions. One of the meanings to assure composite action of composite steel-concrete slabs is prepressed embossments. Its main disadvantage is that the design of a new type of sheeting requires expensive and time consuming large-scale laboratory testing which hamper its widespread commercial usage. Small-scale shear tests present a less expensive alternative to the large-scale tests but its results cannot be simply used for the design of the whole slab. The results from small-scale tests with different options are compared in this paper. Also a possibility of contribution of FE simulation results to the small-scale tests usage is investigated.

scholarly journals Vitrification of High-Level Radioactive Waste in a Small-Scale Joule-Heated Ceramic Melter

1981 ◽  
Vol 6 ◽  
Author(s):  
Gerald B. Woolsey ◽  
M. John Plodinec
Keyword(s):  
Radioactive Waste ◽  
Large Scale ◽  
Liquid Waste ◽  
Glass Frit ◽  
Small Scale ◽  
Savannah River ◽  
Savannah River Plant ◽  
Reference Process ◽  
High Level ◽  
Large Scale Tests

ABSTRACTVitrification is the reference process for the immobilization of radioactive waste from the production of defense materials at the Savannah River Plant (SRP). Since 1979, a small vitrification facility (1 Ib/hr) has been operated at the Savannah River Laboratory using actual SRP waste. In previous studies. dried waste was fed to this smaller melter. This report discusses direct feeding of actual liquid-waste slurries to the small melter. These liquidfeeding tests demonstrated that addition of premelted glass frit to the waste slurry reduces the amount of material volatilized. Results of these tests are in accord with results of large-scale tests with actual waste.

scholarly journals LARGE VERIFICATION TESTS ON ROCK SLOPE STABILITY

1988 ◽  
Vol 1 (21) ◽  
pp. 157
Author(s):  
J.W. Van der Meer ◽  
K.W. Pilarczyk
Keyword(s):  
Large Scale ◽  
Scale Effects ◽  
Rock Slope Stability ◽  
Small Scale ◽  
Rock Slopes ◽  
Ripple Formation ◽  
Scale Test ◽  
Gravel Beaches ◽  
The Stability ◽  
Large Scale Tests

A number of large scale tests on stability of rock slopes and gravel beaches is described and compared with small scale test results. The following topics are treated: the stability of a rock armour layer, the profile formation of a berm breakwater, the profile formation of gravel beaches, including ripple formation, and reflection and overtopping on rock slopes. The general conclusion is that scale effects could not be found.

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