Best Practices for Yield Stress Determination Using the Flattened Strap Tensile Test

2014 ◽  
Author(s):  
L. E. Collins ◽  
M. Rashid
Keyword(s):  
Best Practices ◽  
Tensile Properties ◽  
Yield Stress ◽  
Tensile Testing ◽  
Best Practice ◽  
Tensile Specimen ◽  
Flat Plates ◽  
Step Method ◽  
Line Pipe ◽  
Flattening Process

The tensile properties of line pipe are usually determined using a flattened strap tensile sample which is obtained by cutting a long transverse sample from the pipe and then flattening it prior to machining the final tensile coupon. Although, several documents have been published to standardize this test, variability in the reported yield stress for the same material tested by different labs continues to be an issue particularly in high strength line pipe (X70 and X80). Pipe properties are influenced by the pipe forming operations which introduce plastic strain into the steel. As well, the flattening of the tensile blank reverses the deformation and leads to Bauchinger effects which further alter the tensile properties of the material. There is no standard available for the flattening process and pipe manufacturers and operators continue to seek a best practice for the process. In addition, other factors such as placement of extensometer on a flattenend tensile specimen during the tensile testing have been considered a source of variation in the results. Several projects were conducted to identify the source of variability and to standardize the flattening and testing process among the Evraz QA Labs. These initiatives included: a round robin tensile testing program in which tensile tests were performed on flat plates and subsequently on flattened strap specimens produced from a sister plate; examination of a 2-step flattening procedure against a 1-step method, and investigation of the extensometer placement (ID, OD or side mounted) on the recorded stress-strain behaviour. The flattening process was found to be the main source of variability of yield stress. No real trend was observed resulting from extensometer position. Other testing practices such as specimen gripping, zeroing the load and positioning at the start of the test, and the dimensional variability within the reduced section of a specimen were also found to contribute to yield stress variability. Best practices for determination of yield stress using flattened strap tensile samples are discussed.

The Effect of Sample Flattening on Yield Strength Measurement in Line Pipe

2010 ◽  
Author(s):  
Dave G. Crone ◽  
Laurie E. Collins ◽  
Yankui Bian ◽  
Paul Weber
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Tensile Testing ◽  
Measurement Techniques ◽  
Base Material ◽  
Ring Expansion ◽  
Tensile Specimen ◽  
Forming Process ◽  
Line Pipe ◽  
Ongoing Research

Tensile testing is a key part of the qualification process of Line Pipe. When qualifying pipe products various items are considered when tensile testing; Yield Strength (YS), Ultimate Tensile Strength (UTS), Percent Elongation (%EL), and the Yield Strength to Tensile Strength Ratio (Y/T) are all important. Of these, the YS is the most critical and yet the most sensitive to both preparation and measurement techniques. During the pipe forming process, the base material is plastically formed into a curved shape, and then welded into the final product. The Transverse to Pipe Axis (TPA) tensile specimen removed for testing is curved and must be flattened prior to testing. The flattening process is varied in many facilities and the standards to which testing is conducted are not specific enough to ensure uniformity of procedures. ASTM acknowledges flattening processes and the degree of flatness “may affect test results”, though no guidance is given. This paper will provide an overview of ongoing research efforts, concerning the measurement of the Yield Strength of TPA tensile specimens and its relationship to curvature and flattening methods, prior to testing. By comparing flattened strap tests, to round bar and ring expansion tests, it is shown that the flattened strap test provides a conservative estimate of the actual YS of the pipe.

Comparison of Ring Expansion vs Flat Tensile Testing for Determining Linepipe Yield Strength

1996 ◽  
Author(s):  
Wahib E. Saikaly ◽  
William D. Bailey ◽  
Laurie E. Collins
Keyword(s):  
Standard Deviation ◽  
Yield Strength ◽  
Yield Stress ◽  
Tensile Testing ◽  
Accurate Determination ◽  
Tensile Tests ◽  
Ring Expansion ◽  
Tensile Specimen ◽  
Ring Test ◽  
Ring Testing

Ring expansion testing has been compared to conventional tensile testing as a means to evaluate the circumferential yield strength of pipe products. It was found that ring expansion testing provides a more accurate determination of hoop yield stress than tensile testing of flattened pipe samples. In addition, ring testing was found to be more sensitive to the metallurgical condition of the steel. Tests were conducted on ERW and Spiral pipes. Different grades and diameter to thickness (D/t) ratios were evaluated. In comparison to tensile testing on flattened specimens, ring expansion tests gave: a) higher yield strength; and b) reduced standard deviation in test data. The difference in yield strength measured by ring and tensile tests increased with increasing grade and lower D/t. The higher yield strength measured in the ring test is a result of reducing the Bauschinger effect associated with flattening tensile samples. The reduced standard deviation is due to the elimination of flatness and machining variations that occur on a flattened tensile specimen. It was concluded that ring testing provides a true measure of pipe circumferential yield stress.

scholarly journals Fluctuating Asymmetry and Developmental Instability, a Guide to Best Practice

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 9
Author(s):  
John H. Graham
Keyword(s):  
Measurement Error ◽  
Best Practices ◽  
Environmental Stress ◽  
Fluctuating Asymmetry ◽  
Best Practice ◽  
Developmental Instability ◽  
The Past ◽  
Size Scaling ◽  
Research Designs

Best practices in studies of developmental instability, as measured by fluctuating asymmetry, have developed over the past 60 years. Unfortunately, they are haphazardly applied in many of the papers submitted for review. Most often, research designs suffer from lack of randomization, inadequate replication, poor attention to size scaling, lack of attention to measurement error, and unrecognized mixtures of additive and multiplicative errors. Here, I summarize a set of best practices, especially in studies that examine the effects of environmental stress on fluctuating asymmetry.

Evaluation of the mixing quality of high-viscosity yield stress fluids in a tubular reactor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Le Xie ◽  
Guangwen He ◽  
Bin Yu ◽  
Shaowei Yan
Keyword(s):  
Yield Stress ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Time History ◽  
High Viscosity ◽  
Cfd Model ◽  
Step Method ◽  
Mean Velocity ◽  
Mixing Quality

Abstract In this study, the mixing quality of high-viscosity yield stress fluid (Carbopol aqueous solution) under laminar and turbulent flow regimes was evaluated through a numerical experimental study. A three-dimensional computational fluid dynamics large-eddy simulation (CFD-LES) model was employed to capture large-scale vortex structures. The proposed CFD model was validated by the experimental data in terms of mean velocity profiles and velocity-time history. Thereafter, the CFD model was applied to simulate the residence time distribution using the tracking technique: tracer pulse method and step method. In addition, the non-ideal flow phenomena caused by molecular diffusion and eddy diffusion were evaluated. The effects of the rheological properties on the mixing performance were also investigated. The presented results can provide useful guidance to enhance mass transfer in reactors with high-viscosity fluids.

Abstract 218: Expanding a Learning Collaborative Model in Chicago to Improve Door to Needle for Stroke Thrombolysis: Raising the Bar

2017 ◽  
Vol 10 (suppl_3) ◽  
Author(s):  
Shyam Prabhakaran ◽  
Renee M Sednew ◽  
Kathleen O’Neill
Keyword(s):  
Best Practices ◽  
Performance Improvement ◽  
Best Practice ◽  
Learning Collaborative ◽  
Collaborative Model ◽  
Stroke Registry ◽  
Chicago Area ◽  
Regional Collaboration ◽  
Content Expert ◽  
And Performance

Background: There remains significant opportunities to reduce door-to-needle (DTN) times for stroke despite regional and national efforts. In Chicago, Quality Enhancement for the Speedy Thrombolysis for Stroke (QUESTS) was a one year learning collaborative (LC) which aimed to reduce DTN times at 15 Chicago Primary Stroke Centers. Identification of barriers and sharing of best practices resulted in achieving DTN < 60 minutes within the first quarter of the 2013 initiative and has sustained progress to date. Aligned with Target: Stroke goals, QUESTS 2.0, funded for the 2016 calendar year, invited 9 additional metropolitan Chicago area hospitals to collaborate and further reduce DTN times to a goal < 45 minutes in 50% of eligible patients. Methods: All 24 hospitals participate in the Get With The Guidelines (GWTG) Stroke registry and benchmark group to track DTN performance improvement in 2016. Hospitals implement American Heart Association’s Target Stroke program and share best practices uniquely implemented at sites to reduce DTN times. The LC included a quality and performance improvement leader, a stroke content expert, site visits and quarterly meetings and learning sessions, and reporting of experiences and data. Results: In 2015, the year prior to QUESTS 2.0, the proportion of patients treated with tPA within 45 minutes of hospital arrival increased from 21.6% in Q1 to 31.4% in Q2. During the 2016 funded year, this proportion changed from 31.6% in Q1 to 48.3% in Q2. Conclusions: Using a learning collaborative model to implement strategies to reduce DTN times among 24 Chicago area hospitals continues to impact times. Regional collaboration, data sharing, and best practice sharing should be a model for rapid and sustainable system-wide quality improvement.

scholarly journals Are Best Practices Really Best? A Review of the Best Practices Literature in Library and Information Studies

2013 ◽  
Vol 8 (4) ◽  
pp. 110 ◽  
Author(s):  
Jackie Druery ◽  
Nancy McCormack ◽  
Sharon Murphy
Keyword(s):  
Best Practices ◽  
Best Practice ◽  
Information Science ◽  
Library And Information Science ◽  
Science Literature ◽  
Common Definition ◽  
Library And Information Studies ◽  
Information Studies ◽  
The Subject ◽  
Definition Of

Objective - The term “best practice” appears often in library and information science literature, yet, despite the frequency with which the term is used, there is little discussion about what is meant by the term and how one can reliably identify a best practice. Methods – This paper reviews 113 articles that identify and discuss best practices, in order to determine how “best practices” are distinguished from other practices, and whether these determinations are made on the basis of consistent and reliable evidence. The review also takes into account definitions of the term to discover if a common definition is used amongst authors. Results – The “evidence” upon which papers on “best practices” are based falls into one of the following six categories: 1) opinion (n=18, 15%), 2) literature reviews (n=13, 12%), 3) practices in the library in which the author works (n=19, 17%), 4) formal and informal qualitative and quantitative approaches (n=16, 14%), 5) a combination of the aforementioned (i.e., combined approaches) (n=34, 30%), and 6) “other” sources or approaches which are largely one of a kind (n=13, 12%). There is no widely shared or common definition of “best practices” amongst the authors of these papers, and most papers (n=94, 83%) fail to define the term at all. The number of papers was, for the most part, split evenly amongst the six categories indicating that writers on the subject are basing “best practices” assertions on a wide variety of sources and evidence. Conclusions – Library and information science literature on “best practices” is rarely based on rigorous empirical methods of research and therefore is generally unreliable. There is, in addition, no widely held understanding of what is meant by the use of the term.

scholarly journals The Intertwining Impact of Intraorganizational and Routine Networks on Routine Replication Dynamics: An Agent-Based Model

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Dehua Gao ◽  
Flaminio Squazzoni ◽  
Xiuquan Deng
Keyword(s):  
Best Practices ◽  
Best Practice ◽  
Network Effects ◽  
Fitness Landscape ◽  
Optimal Combination ◽  
Landscape Model ◽  
Agent Based ◽  
Adaptive Changes ◽  
Absorptive Capacities ◽  
Geographically Distributed

Organizational routines are means through which organizations can reutilize best practices and so their replication, i.e., duplicating beneficial routines across context, is a key value-creating strategy. However, it is difficult to map network effects on routine replication. Here, we investigated routine replicating dynamics considering two types of network contexts, namely, (1) connections between different (geographically distributed) units in a decentralized organization and (2) the coupling relation between routines, i.e., a bundle of different routines involved in each unit. By considering routine replication as one kind of template-based activities between different units, we examined interrelations between routines with a NK-based fitness landscape model. Our results show that when there is an appropriate level of absorptive capacities (i.e., when organizations are capable of identifying and acquiring externally generated knowledge), there is an optimal combination of these two types of networks, which is beneficial to routine replicating practices and organization adaptation. Furthermore, we also found that intraorganizational variations, including template-duplicating errors and innovative activities, are instrumental to enhance adaptive changes. Our findings suggest measures to control and manage best practice diffusion across organizations.

scholarly journals Engaging Multidisciplinary Stakeholders to Drive Shared Decision-Making in Oncology

2018 ◽  
Vol 34 (1) ◽  
pp. 29-31 ◽  
Author(s):  
Gabrielle Rocque ◽  
Ellen Miller-Sonnet ◽  
Alan Balch ◽  
Carrie Stricker ◽  
Josh Seidman ◽  
...  
Keyword(s):  
Health Care ◽  
Decision Making ◽  
Best Practices ◽  
Shared Decision Making ◽  
Best Practice ◽  
Care Delivery ◽  
Evidence Based ◽  
Shared Decision ◽  
Oncology Practice ◽  
Development And Validation

Although recognized as best practice, regular integration of shared decision-making (SDM) approaches between patients and oncologists remains an elusive goal. It is clear that usable, feasible, and practical tools are needed to drive increased SDM in oncology. To address this goal, we convened a multidisciplinary collaborative inclusive of experts across the health-care delivery ecosystem to identify key principles in designing and testing processes to promote SDM in routine oncology practice. In this commentary, we describe 3 best practices for addressing challenges associated with implementing SDM that emerged from a multidisciplinary collaborative: (1) engagement of diverse stakeholders who have interest in SDM, (2) development and validation of an evidence-based SDM tool grounded within an established conceptual framework, and (3) development of the necessary roadmap and consideration of the infrastructure needed for engendering patient engagement in decision-making. We believe these 3 principles are critical to the success of creating SDM tools to be utilized both within and outside of clinical practice. We are optimistic that shared use across settings will support adoption of this tool and overcome barriers to implementing SDM within busy clinical workflows. Ultimately, we hope that this work will offer new perspectives on what is important to patients and provide an important impetus for leveraging patient preferences and values in decision-making.

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