Development of a methodical approach for uncertainty quantification and meta-modeling of surface hardness in white layers of longitudinal turned AISI4140 surfaces

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniel Gauder ◽  
Michael Biehler ◽  
Johannes Gölz ◽  
Benedict Stampfer ◽  
David Böttger ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Uncertainty Quantification ◽  
Mean Squared Error ◽  
Surface Hardness ◽  
Outer Diameter ◽  
Near Surface ◽  
Uncertainty In Measurement ◽  
Methodical Approach ◽  
Surface Microstructures ◽  
Longitudinal Turning

Abstract The formation of thermally and mechanically induced near-surface microstructures in the form of white layers leads to different hardness properties in these areas. Therefore, this paper conducts systematic surface hardness measurements and uncertainty quantification utilizing the Monte Carlo Method (MCM) in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM). Furthermore, several meta-models describing the hardness course in relationship to the material depth are used to model this nonlinear relationship via machine learning. The evaluation and selection of the optimal model considers the trade-off between measurement uncertainty and prediction quality in terms of mean squared error (MSE). The resulting measurement uncertainty is to be used for the calibration of a non-destructive micromagnetic material sensor. This will then be implemented for in-process monitoring in the outer diameter longitudinal turning process. This should make it possible to detect white layers during machining and to avoid them accordingly by controlling the machine parameters. By means of a soft sensor, the corresponding target value is to be derived from the micromagnetic material sensor measurement.

ISO/TS 20914:2019 – a critical commentary

2020 ◽  
Vol 58 (8) ◽  
pp. 1182-1190 ◽  
Author(s):  
Ian Farrance ◽  
Robert Frenkel ◽  
Tony Badrick
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Data ◽  
International Normalized Ratio ◽  
Medical Laboratory ◽  
Uncertainty In Measurement ◽  
Medical Laboratories ◽  
Functional Relationships ◽  
Critical Commentary ◽  
Combined Uncertainty ◽  
Expression Of Uncertainty

AbstractThe long-anticipated ISO/TS 20914, Medical laboratories – Practical guidance for the estimation of measurement uncertainty, became publicly available in July 2019. This ISO document is intended as a guide for the practical application of estimating uncertainty in measurement (measurement uncertainty) in a medical laboratory. In some respects, the guide does indeed meet many of its stated objectives with numerous very detailed examples. Even though it is claimed that this ISO guide is based on the Evaluation of measurement data – Guide to the expression of uncertainty in measurement (GUM), JCGM 100:2008, it is with some concern that we believe several important statements and statistical procedures are incorrect, with others potentially misleading. The aim of this report is to highlight the major concerns which we have identified. In particular, we believe the following items require further comment: (1) The use of coefficient of variation and its potential for misuse requires clarification, (2) pooled variance and measurement uncertainty across changes in measuring conditions has been oversimplified and is potentially misleading, (3) uncertainty in the results of estimated glomerular filtration rate (eGFR) do not include all known uncertainties, (4) the international normalized ratio (INR) calculation is incorrect, (5) the treatment of bias uncertainty is considered problematic, (6) the rules for evaluating combined uncertainty in functional relationships are incomplete, and (7) specific concerns with some individual statements.

Evaluating temperature extremes in CMIP6 simulations using statistically proper evaluation methods

2021 ◽  
Author(s):  
Thordis Thorarinsdottir ◽  
Jana Sillmann ◽  
Marion Haugen ◽  
Nadine Gissibl ◽  
Marit Sandstad
Keyword(s):  
Air Temperature ◽  
Model Evaluation ◽  
Climate Models ◽  
Climate Model ◽  
Mean Squared Error ◽  
Surface Air Temperature ◽  
Cmip5 Models ◽  
Model Output ◽  
Intergovernmental Panel ◽  
Near Surface

<p>Reliable projections of extremes in near-surface air temperature (SAT) by climate models become more and more important as global warming is leading to significant increases in the hottest days and decreases in coldest nights around the world with considerable impacts on various sectors, such as agriculture, health and tourism.</p><p>Climate model evaluation has traditionally been performed by comparing summary statistics that are derived from simulated model output and corresponding observed quantities using, for instance, the root mean squared error (RMSE) or mean bias as also used in the model evaluation chapter of the fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Both RMSE and mean bias compare averages over time and/or space, ignoring the variability, or the uncertainty, in the underlying values. Particularly when interested in the evaluation of climate extremes, climate models should be evaluated by comparing the probability distribution of model output to the corresponding distribution of observed data.</p><p>To address this shortcoming, we use the integrated quadratic distance (IQD) to compare distributions of simulated indices to the corresponding distributions from a data product. The IQD is the proper divergence associated with the proper continuous ranked probability score (CRPS) as it fulfills essential decision-theoretic properties for ranking competing models and testing equality in performance, while also assessing the full distribution.</p><p>The IQD is applied to evaluate CMIP5 and CMIP6 simulations of monthly maximum (TXx) and minimum near-surface air temperature (TNn) over the data-dense regions Europe and North America against both observational and reanalysis datasets. There is not a notable difference between the model generations CMIP5 and CMIP6 when the model simulations are compared against the observational dataset HadEX2. However, the CMIP6 models show a better agreement with the reanalysis ERA5 than CMIP5 models, with a few exceptions. Overall, the climate models show higher skill when compared against ERA5 than when compared against HadEX2. While the model rankings vary with region, season and index, the model evaluation is robust against changes in the grid resolution considered in the analysis.</p>

scholarly journals Surface composition and near-surface hardness studies on high dose boron-implanted 304 stainless steel

1990 ◽  
Vol 13 (5) ◽  
pp. 333-342 ◽  
Author(s):  
A K Goel ◽  
N D Sharma ◽  
R K Mohindra ◽  
P K Ghosh ◽  
M C Bhatnagar
Keyword(s):  
Stainless Steel ◽  
Surface Composition ◽  
Surface Hardness ◽  
304 Stainless Steel ◽  
High Dose ◽  
Near Surface

Crude Furnace Creep Assessment and High Temperature Degradation

2017 ◽  
Author(s):  
Gary Y. H. Lee ◽  
Ohgeon Kwon ◽  
Zuwairi Ramli ◽  
Zaki Mohamad Afifi
Keyword(s):  
High Temperature ◽  
Decision Tree ◽  
Degradation Mechanism ◽  
Surface Hardness ◽  
Furnace Operation ◽  
Outer Diameter ◽  
Final Decision ◽  
High Temperature Properties ◽  
Current Limit ◽  
Life Fraction

Creep calculations indicate a crude furnace radiant section carbon steel tubes exceeding their life fraction due to flame impingement reaching up to 700°C for a year. The ambiguity of the temperature and material data means the life fraction of creep calculations were based on limited inspection data and infra-red scanning giving a conservative indication of end of life. Due to unavailable tubes in stock, a planned pit stop cannot be arranged due to economic and safety reasons as the furnace may not be started back up safely. To safeguard the integrity of the furnace until the planned outage, the temperature on the furnace tube was stabilized to a current limit of 540°C through improvements in burner operations. The crude diet was also maintained within the crude acceptance envelope. Visual checks at every shift were done to ensure no observation from tube bulging or uneven flame pattern. A decision tree was created to facilitate quick decision making using a go/no go criteria of which tubes to replace during the August 2015 planned turnaround. The criteria set for the decision tree required tube wall thickness, surface hardness test, tube outer diameter ring gauge to be examined. Failing any of the criteria will require the tube to be replaced. The replaced tubes (one worst and one representative) will also be lab tested through destructive examination to identify the degradation mechanism and high temperature properties of the worst tubes to quantitatively define the high temperature properties and life fraction of the tubes that are left in the furnace. The lab test will provide results after a year of creep testing and can give assurance of continued furnace operation for 4 more years until the next outage. The final decision after the examination based on the decision tree was made required 17 tubes to be replaced in this turnaround. The worst degraded tubes were found to be at the vicinity of the initial observed location around the flame impingement zone.

Measurement of Residual Stresses within a PWR Swaged Heater Tube

2011 ◽  
Vol 70 ◽  
pp. 279-284 ◽  
Author(s):  
D.M. Goudar ◽  
Ed J. Kingston ◽  
Mike C. Smith ◽  
Sayeed Hossain
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Measurement ◽  
Measurement Techniques ◽  
Residual Stress Distribution ◽  
Hole Drilling ◽  
Shear Stresses ◽  
Outer Diameter ◽  
Near Surface ◽  
Heater Tube

Frequent failures of the pressuriser heater tubes used in Pressurised Water Reactors (PWRs) have been found. Axial cracks initiating from the tube outer diameter have been detected in some tubes as well as the resulting electrical problems. Replacement of the heater tubes requires an undesirably prolonged plant shutdown. In order to better understand these failures a series of residual stress measurements were carried out to obtain the near surface and through-thickness residual stress profiles in a stainless steel pressuriser heater tube. Three different residual stress measurement techniques were employed namely, Deep-Hole Drilling (DHD), Incremental Centre Hole Drilling (ICHD) and Sachs’ Boring (SB) to measure the through thickness residual stress distribution in the heater tubes. Results showed that the hoop stresses measured using all three techniques were predominantly tensile at all locations, while the axial stresses were found to be tensile at the surface and both tensile and compressive as they reduce to small magnitudes within the tube. The magnitude of the in-plane shear stresses was small at all measurement depths at all locations. The various measurement methods were found to complement each other well. All the measurements revealed a characteristic profile for the through-thickness residual stress distribution.

Substrate composition effects on the interfacial fracture of tantalum nitride films

1999 ◽  
Vol 14 (6) ◽  
pp. 2306-2313 ◽  
Author(s):  
N. R. Moody ◽  
A. Strojny ◽  
D. L. Medlin ◽  
A. Talin ◽  
W. W. Gerberich
Keyword(s):  
Aluminum Nitride ◽  
Surface Hardness ◽  
Tantalum Nitride ◽  
Nitride Film ◽  
Interface Composition ◽  
Near Surface ◽  
Substrate Composition ◽  
A Value ◽  
Composition And Structure ◽  
Film Substrate

In this study we combined nanoscratch testing with a multilayer sapphire and aluminum nitride single-substrate system to determine the effects of interface composition and structure on susceptibility to fracture of hard, thin tantalum nitride films. Nanoindentation tests showed that the elastic moduli of the tantalum nitride and aluminum nitride films, as well as the sapphire substrate, were essentially equal at 400 GPa. On both portions of the substrate, these tests also showed that near surface hardness was near 35 GPa. Nanoscratch tests triggered long blisters and circular spalls on both the sapphire and aluminum nitride portions of the substrate. The blisters showed that the tantalum nitride film was subjected to a compressive residual stress of −6.7 GPa. The spalls showed that failure occurred along the tantalum nitride film-substrate interface regardless of substrate composition. Most importantly, the blisters and spalls showed that the mode I componentof the fracture energies was essentially equal on both substrate materials at a value near 3.1 J/m2. These energies are on the order of the energies for metallic bonding.

Uncertainty Calculation of Roundness by Automatic Differentiation

2010 ◽  
Vol 437 ◽  
pp. 217-221
Author(s):  
Jia Chun Lin ◽  
Michael Paul Krystek ◽  
Zhao Yao Shi
Keyword(s):  
Measurement Uncertainty ◽  
Automatic Differentiation ◽  
Uncertainty In Measurement ◽  
Uncertainty Calculation ◽  
Measurement Results ◽  
Coordinate Metrology ◽  
Data Points ◽  
Roundness Deviation ◽  
Expression Of Uncertainty ◽  
Roundness Measurement

According to the Guide to the Expression of Uncertainty in Measurement (GUM), all measurement results must have a stated uncertainty associated to them. But in most cases of roundness measurement either no uncertainty value is given, or the calculation is not based on the model of the respective association criterion for the geometrical feature, because no suitable measurement uncertainty calculation procedure does exist. For the case of roundness measurement in coordinate metrology, this paper will suggest algorithms for the calculation of the measurement uncertainty of the roundness deviation based on the two mainly used association criteria LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculation can be done by automatic differentiation, in order to avoid introducing additional errors by the traditional difference quotient approximations. The proposed methods are exact and need as input data only the measured co-ordinates of the data points and their associated uncertainties.

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