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.

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.

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

Spatial Perspectives on Coworking Spaces and Related Practices in Beijing

2020 ◽  
Vol 46 (1) ◽  
pp. 40-54
Author(s):  
He Huang ◽  
Yangfanqi Liu ◽  
Yuebing Liang ◽  
David Vargas ◽  
Lu Zhang
Keyword(s):  
Large Scale ◽  
Driving Forces ◽  
Empirical Studies ◽  
Analytical Framework ◽  
Sharing Economy ◽  
Small Scale ◽  
The Sustainable Development ◽  
Knowledge Economies ◽  
Coworking Spaces ◽  
The City

Coworking space is a recent manifestation of the emerging sharing economy. This is largely due to two core driving forces: a new working style in the creative and knowledge economies, and the sharing economy, which promotes resource usage efficiency. This paper develops an analytical framework for the spatial perspectives on coworking spaces according to the core driving forces at both the urban and architectural levels, followed by empirical studies on practices related to coworking space in Beijing. The results indicate that at the city scale, coworking spaces tend to aggregate in clusters of large-scale creative and knowledge enterprises in mixed-use and high-density areas, and underutilized spaces become the key pillar. In the architectural dimension, coworking spaces tend to coexist with conventional office spaces or coliving apartments. Empirical studies in Beijing also show that coworking spaces have promoted the sustainable development of the city by renewing existing low-profit urban spaces and utilizing architectural spaces more efficiently. However, the unstable lease market of small-scale businesses, as well as marginal financial models, which pro fit from rental differences, challenge the survival of coworking spaces. In pursuit of capital, coworking spaces have tended to overexpand.

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.

Driving Forces of Landscape Change at the Upriver of Minjiang, China

2011 ◽  
Vol 219-220 ◽  
pp. 532-537 ◽  
Author(s):  
Yong Hua Zhao ◽  
Xiao Feng Wang
Keyword(s):  
Landscape Change ◽  
Large Scale ◽  
Technology Policy ◽  
Driving Forces ◽  
Good Method ◽  
Human Dimensions ◽  
Small Scale ◽  
Planned Parenthood ◽  
Household Level ◽  
The Great Leap Forward

Research into landscape change was one of two major fields of interdisciplinary research into the human dimensions of environmental change, the other being the approach of socio-economic metabolism; the causes of which were complicated and comprehensive. Based on the household level interview, analyzing the causes of change by the multifactor was a good method. We applied the household level interview data to analyze the causes of landscape cover change at the upper reach of Minjiang, China. The causes of landscape change at the upper reach of Minjiang included agriculture, wood, infrastructure, economy, technology, policy & institution, demography and culture variables, etc. The results showed that the primary causes of landscape change at the upper reach of Minjiang were the correlative country policies (such as the Great Leap Forward, the Deforestation, the Institutional Revolution, the Planned Parenthood, the Open-up, the Natural Forest Conservation Program) and triggered event (such as the three years’ natural disaster) at the large scale, however, at the small scale such as at the village level, the principal cause of which was different, and there were the interplay among different factors. So we thought that the landscape cover change was the result of multifactor interplay at the upper reach of Minjiang, China.

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.

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