scholarly journals Design study for a multicomponent transducer for wind turbine test benches

2020 ◽  
Vol 9 (2) ◽  
pp. 239-249
Author(s):  
Jonas Gnauert ◽  
Georg Jacobs ◽  
Stefan Kock ◽  
Dennis Bosse ◽  
Benjamin Janik
Keyword(s):  
Measurement Uncertainty ◽  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Design Study ◽  
Operational Conditions ◽  
Uncertainty In Measurement ◽  
Fe Simulations ◽  
Transducer Design ◽  
6 Degrees Of Freedom ◽  
Expression Of Uncertainty

Abstract. This paper covers the design study of a multicomponent transducer (MCT) for wind turbine test benches. The MCT will cover the characteristics of wind turbines in the power range of up to 6 MW. The motivation to develop a MCT such as this is to provide satisfying measurement accuracy of loads and moments for all 6 degrees of freedom in order to reduce the uncertainty in the traceability of the drive train behavior due to the applied loads. Therefore, the estimation of the measurement uncertainty is significant with respect to evaluating the design of the MCT. First, the design process of the MCT is briefly introduced. Second, the strain-gauge-based transducer design is investigated under operational conditions (e.g., torque and multiaxial loads) using finite element (FE) simulations to determine the crosstalk effects. Finally, the measurement uncertainties of all quantities are estimated based on these FE simulations according to the type B evaluation of the “Guide to the Expression of Uncertainty in Measurement” (GUM; JCGM, 2010), including metrological aspects (e.g., linearity deviation and hysteresis) and the crosstalk. It can be shown that the MCT has great potential to significantly improve the measurement uncertainty for the applied wind loads on a wind turbine test bench.

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.

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.

Uncertainty Analysis of Helical Deviation Measurements

2010 ◽  
Vol 437 ◽  
pp. 212-216 ◽  
Author(s):  
Zhao Yao Shi ◽  
Jia Chun Lin ◽  
Michael Paul Krystek
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Errors ◽  
National Standards ◽  
Calculation Procedure ◽  
Uncertainty In Measurement ◽  
Uncertainty Calculation ◽  
Measurement Results ◽  
Polar Coordinate ◽  
Expression Of Uncertainty ◽  
Dynamical Measurement

The helix is a complex geometrical element. During the process of a dynamical measurement of the helical deviations, many factors, including the machine and the environment, lead to measurement errors. Although ISO as well as national standards stipulate the tolerances and assessment methods for helical deviations, these standards contribute little to the uncertainty calculations concerning such measurements. 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 helical deviation measurements, no uncertainty value is given, simply because no measurement uncertainty calculation procedure exists. For the case of helical deviation measurements on a Computer Numeric Control (CNC) polar coordinate machine, this paper analyses in detail all kinds of factors contributing to the measurement uncertainty, and gives the calculation procedure of the measurement uncertainty of helical deviation. As an example, the calculation of the measurement uncertainty of the helical deviations of a worm is presented.

scholarly journals A General Mathematical Approach Based on the Possibility Theory for Handling Measurement Results and All Uncertainties

Metrology ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 76-92
Author(s):  
Simona Salicone ◽  
Harsha Vardhana Jetti
Keyword(s):  
Measurement Uncertainty ◽  
Possibility Theory ◽  
Mathematical Approach ◽  
Lexical Meaning ◽  
Uncertainty In Measurement ◽  
Complete Knowledge ◽  
Measurement Results ◽  
The One ◽  
Expression Of Uncertainty

The concept of measurement uncertainty was introduced in the 1990s by the “Guide to the expression of uncertainty in measurement”, known as GUM. The word uncertainty has a lexical meaning and reflects the lack of exact knowledge or lack of complete knowledge about the value of the measurand. Thanks to the suggestions in the GUM and following the mathematical probabilistic approaches therein proposed, an uncertainty value can be found and be associated to the measured value. In the last decades, however, other methods have been proposed in the literature, which try to encompass the definitions of the GUM, thus overcoming its limitations. Some of these methods are based on the possibility theory, such as the one known as the RFV method. The aim of this paper is to briefly recall the RFV method, starting from the very beginning and the initial motivations, and summarize in a unique paper the most relevant obtained results.

scholarly journals Uncertainties of ISO 3382-3 sound pressure level quantities

Acta Acustica ◽  
2021 ◽  
Vol 5 ◽  
pp. 27
Author(s):  
Moritz Schneider ◽  
Jan Selzer ◽  
Jörg Rissler ◽  
Andrea Wolff ◽  
Florian Schelle
Keyword(s):  
Measurement Uncertainty ◽  
Sound Pressure ◽  
Technical Note ◽  
Acoustic Properties ◽  
Mathematical Framework ◽  
Limit Values ◽  
Uncertainty In Measurement ◽  
Uncertainty Estimates ◽  
Open Plan ◽  
Expression Of Uncertainty

The ISO 3382-3 standard uses the measurable sound pressure based parameters D2,S and Lp,A,S,4 m to describe the acoustic properties of open-plan offices. As yet however, no treatment of the measurement uncertainty of these parameters according to the Guide to the expression of Uncertainty in Measurement (GUM) is to be found in the peer-reviewed literature. This technical note therefore describes how the measurement uncertainty can be declared according to GUM. The mathematical framework presented here can be used and expanded by other laboratories to derive their own uncertainty estimates. It is also applied in this document to 44 measurements yielding combined uncertainties for D2,S of 0.55 dB ≤ $ {\sigma }_{c,{D}_{2,\mathrm{S}}}$ ≤ 0.67 dB and for Lp,A,S,4 m of 0.19 dB ≤ $ {\sigma }_{c,{L}_{p,\mathrm{A},\mathrm{S},4\enspace \mathrm{m}}}$ ≤ 0.83 dB. The implications of this result are discussed with regard to limit values in technical regulations.

Multibody Dynamics of a Floating Wind Turbine Considering the Flexibility Between Nacelle and Tower

2018 ◽  
Vol 18 (06) ◽  
pp. 1850085 ◽  
Author(s):  
Vahid Jahangiri ◽  
Mir Mohammad Ettefagh
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Multibody System ◽  
Equations Of Motion ◽  
System Response ◽  
Floating Wind Turbine ◽  
Conservation Of Momentum ◽  
The Stability ◽  
Nonlinear Equations Of Motion ◽  
6 Degrees Of Freedom

Stability and dynamic modeling of the floating wind turbine (FWT) is a crucial challenge in designing of the type of structures. In this paper, the tension leg platform (TLP) type FWT is modeled as a multibody system considering the flexibility between the nacelle and tower. The flexibility of the FWT is modeled as a torsional spring and damper. It has 6 degrees of freedom (DOFs) related to the large-amplitude translation and rotation of the tower and 4 DOFs related to the relative rotation between the rotor-nacelle assembly and the tower. First, the nonlinear equations of motion are derived by the theory of momentum cloud based on the conservation of momentum. Then, the equations of motion are solved and the system is simulated in MATLAB. Moreover, the effect of flexibility between the nacelle and tower is investigated via the dynamic response. The stability of the system in three different environmental conditions is studied. Finally, the spring and damping coefficients for the system response to get near to instability are determined, by which the critical region is defined. The simulation results demonstrate the importance of the flexibility between the nacelle and tower on the overall behavior of the system and its stability.

scholarly journals Design and Manufacture of 6 Axis Force and Moments Transducers for Seaplane Floaters Test in Towing Tank

2020 ◽  
Vol 3 (1) ◽  
pp. 84-89
Author(s):  
Nurhadi Nurhadi ◽  
Mochammad Nasir ◽  
Chandra Permana ◽  
Endah Suwarni
Keyword(s):  
Measurement Errors ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Force Measurements ◽  
Towing Tank ◽  
Simulation Testing ◽  
Transducer Design ◽  
6 Degrees Of Freedom ◽  
Design And Manufacture ◽  
Capture Point

To develop seaplanes as a means of inter-island transportation, it is necessary to have a simulation, testing, and analysis of force measurements that work so that the aircraft can be designed optimally in terms of function and safety. To fulfill one type of test, the seaplane floater model is pulled in the Towing Tank to determine the hydrodynamic forces acting on the floater which include resistance (Fx), side force (Fy), lift force (Fz), and moments in all three axes. A method of measuring the force of 6 axis force and moment or 6 degrees of freedom (6 Degree of Freedom, 6 DOF) was built and designed by combining several single load cells so that these forces can be known optimally. From the results of the 6 DOF transducer design, it is proven that it can be used well in measuring 6 forces and moments with force measurement errors ranging from 1.38%. The distance between the 6 DOF transducer capture point and the floater force capture point will affect the measured moment transformation.

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