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Liste der Veröffentlichungen der Arbeitsgruppe 1.73

Referenzen

2021

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Leonard Klaus und Michael Kobusch
Measurement: Sensors, 18:100149
2021
ISSN: 26659174

Zusammenfassung: Research in the field of dynamic torque calibration has gained some momentum in the last few years. At PTB, a calibration device for small dynamic torque levels up to about 0.5 N m proved the working principle of dynamic torque calibrations with sinusoidal excitation. In a next step, a new calibration device was developed with the intention of generating higher dynamic torque levels in the range of up to 20 N m. Although this is still less than many industrial applications require, it could pave the way to higher torque levels. The new calibration device features a horizontal arrangement of all components of the drive shaft. The device consists mostly of industrial components that have been modified, rather than custom-made components. After commissioning, optimising the device enabled a frequency range from 10 Hz to up to 400 Hz.

2020

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Michael Kobusch und Leonard Klaus
ACTA IMEKO, 9:118
2020
ISSN: 2221-870X

Zusammenfassung: This paper presents experimental investigations of in-situ dynamic force calibrations in which an impact hammer provides the dynamic reference force. Here, the force transducer to be calibrated remains in the original mechanical structure of the force measurement application to which calibration shock forces are applied in a suitable way. Numerous experiments with different force transducer set-ups and different impact hammer configurations were conducted to validate this in- situ calibration method. The paper describes the analysis of the measurement data and presents the force transfer functions obtained. Finally, these dynamic calibration results are discussed.

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Leonard Klaus
ACTA IMEKO, 9:200
2020
ISSN: 2221-870X

Zusammenfassung: Dynamic measurements to correctly adjust the magnitude in fatigue testing require a dynamic calibration of force transducers and conditioning electronics if the dynamic loads are to be measured correctly. International standard ISO 4965 describes a calibration method for these components. At PTB, such a calibration of bridge amplifiers has now been performed for the first time. The calibration includes tests with static and dynamic signals. The reference for the calibration is the dynamic bridge standard of PTB. It is particularly suitable for this application as it can generate static and dynamic signals, and thus all investigations can be performed with one reference and in a reasonably short time. The signal creation and the data analysis were carried out using the open source program GNU Octave. For the data analysis, a semi-automatic procedure was developed to simplify the process. Calibrations of two digital bridge amplifiers were carried out.

2019

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Leonard Klaus, M. Florian Beug und Thomas Bruns
ACTA IMEKO, 8:19
2019
ISSN: 2221-870X

Zusammenfassung: Measurements of mechanical quantities are often carried out with transducers with a bridge output. The output signals are conditioned using bridge amplifiers. If dynamically changing quantities are going to be measured traceably, the bridge amplifier must be calibrated dynamically.This paper describes a dynamic bridge amplifier calibration setup based on the new PTB dynamic bridge standard. The calibration is carried out by the synchronous sampling of the bridge amplifier output voltage and a reference signal provided by the calibrated dynamic bridge standard. The dynamic bridge standard enables calibrations in a frequency range from DC (static calibration) up to 10 kHz. An overview of the different measurement uncertainty contributions is given, and the first measurement results show good agreement with a previously established measurement setup.

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Franck Larsonnier, Guillaume Rouillé, Claire Bartoli, Leonard Klaus und Philipp Begoff
19th International Congress of Metrology (CIM2019) , Seite 27003.
Herausgeber: EDP Sciences, Paris, France
2019
978-2-7598-9069-9

Zusammenfassung: Accelerometer calibration by primary and secondary means is now very well covered both in low and medium frequency range. This is obviously not the case for seismometers which are widely used in the world. Up to now, seismometers only have internal checks thanks to an integrated coil. Calibration of these devices address different challenges like large mass and volumes, non-rotatable devices, specific mounting. This inter laboratory comparison will help to investigate these fields and to give feedback to develop a methodology to calibrate seismometers.

2018

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Leonard Klaus und Sascha Eichstaedt
Metrologia, 55
2018
ISSN: 0026-1394, 1681-7575

Zusammenfassung: For a dynamic calibration, a torque transducer is described by a mechanical model, and the corresponding model parameters are to be identified from measurement data. A measuring device for the primary calibration of dynamic torque, and a corresponding model-based calibration approach, have recently been developed at PTB. The complete mechanical model of the calibration set-up is very complex, and involves several calibration steps—making a straightforward implementation of a Monte Carlo uncertainty evaluation tedious. With this in mind, we here propose to separate the complete model into sub-models, with each sub-model being treated with individual experiments and analysis. The uncertainty evaluation for the overall model then has to combine the information from the sub-models in line with Supplement 2 of the Guide to the Expression of Uncertainty in Measurement. In this contribution, we demonstrate how to carry this out using the Monte Carlo method. The uncertainty evaluation involves various input quantities of different origin and the solution of a numerical optimisation problem.

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Leonard Klaus und Michael Kobusch
Journal of Physics: Conference Series, 1065:222014
2018
ISSN: 1742-6588, 1742-6596

Zusammenfassung: Seismometers are widely used all over the world, but rarely calibrated traceably. PTB analysed its capabilities for seismometer calibration and identified its multi-component acceleration exciter as suitable for carrying the comparably heavy seismometers. Additionally, multi-axial seismometers can be calibrated in all axes without moving the device. The calibration device needed to be analysed and tested for the required small excitation magnitudes and low excitation frequencies. The results show that it is capable of generating small sinusoidal excitation of less than 1 mm/s in a frequency range down to 0.4 Hz. For this purpose, the feedback control needed to be adapted. Additionally, a temperature control of the shaker armature prevents the problem of temperature increase due to hot hydraulic fluids near the armature.The vibrations in all three translational degrees of freedom are measured by laser vibrometers and then processed according to ISO 16063-11 by sine fit procedures.

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Leonard Klaus, Stephan Hannig und Harald Bothe
Journal of Physics: Conference Series, 1065:222015
2018
ISSN: 1742-6588, 1742-6596

Zusammenfassung: It is becoming increasingly important to assess the suitability for transportation of reference standards used for intercomparisons and of scientific devices developed to be transportable. For this purpose, normative documents were analysed in order to find a suitable test schedule, and two devices under test – one inductance standard and one optical cavity – were exposed to acceleration spectra simulating the typical transportation of each of the devices under test for different durations.The different devices under test are described and the motivation for the transport simulation is given. The results of the different tests are presented.

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Marek Spoors
Bachelor-Thesis
Fachhochschule des Mittelstands (FHM),
2018

Zusammenfassung: Die Torsionssteifigkeit von mechanischen Komponenten ist im Bereich der Entwicklung eines modelbasierten Verfahrens zur Kalibrierung von Drehmomentaufnehmern mit dynamischer Anregung eine wichtige Information. Zur Ermittlung der Torsionssteifigkeit wurde ein speziell hierfür geeigneter Messplatz aufgebaut.Die vorliegende Arbeit beschreibt die Erweiterung des bereits vorhandenen Messplatzes für statische Torsionsbelastung durch optische Messmittel. Mit Hilfe der optischen Sensoren kann die Verdrehung während einer Drehmomentbelastung im Messobjekt gemessen werden. Mit dieser Information und dem gemessenen Drehmoment wird dieTorsionssteifigkeit bestimmt. Im Rahmen der Arbeit wurde hierzu ein Messdatenauswertungsprogramm entwickelt, welches die Daten des Messplatzes auswertet und eine Plausibilitätsprüfung der Messwerte durchführt. DieTorsionssteifigkeit wird dabei durch eine Regressionsgerade beschrieben, die mittels des mathematischen Verfahrens, der Methode der kleinsten Quadrate (least squares method), errechnet wurde. Für die gewonnenen Messwerte wurden abschließend die Einzelmessunsicherheitseinflüsse untersucht.

2017

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Michael Kobusch und Sascha Eichstädt
ACTA IMEKO, 6:3
2017
ISSN: 2221-870X

Zusammenfassung: Investigations of the model-based dynamic calibration of a small strain gauge force transducer of high bandwidth revealed new challenges for parameter identification. This paper discusses a more generalized mechanical model of the calibration set-up employed taking account of the transducer’s connection to its mechanical environment at both ends. Based on new experimental sine and shock force data, the improved model is studied and its parameters are identified. It is shown that the proposed model is capable of linking the calibration results of both calibration methods to a much better degree. This paper is an extended version of the original contribution to the IMEKO 2015 conference in Prague, Czech Republic.

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Leonard Klaus
Measurement Science Review, 17
2017
ISSN: 1335-8871

Zusammenfassung: To determine the mass-moment-of-inertia properties of devices under test with particularly small mass moments of inertia (some 10−4 kg m2), two measurement set-ups based on different measurement principles were developed. One set-up is based on a physical pendulum, the second set-up incorporates a torsion pendulum. Both measurement set-ups and their measurement principles are described in detail, including the chosen data acquisition and analysis. Measurement uncertainty estimations according to the Guide to the Expression of Uncertainty in Measurement (GUM) were carried out for both set-ups by applying Monte Carlo simulations. Both set-ups were compared using the same three devices under test. For each measurement result, the measurement uncertainties were estimated. The measurement results are compared in terms of consistency and the resulting measurement uncertainties. For the given devices under test, the torsion pendulum set-up gave results with smaller measurement uncertainties compared to the set-up incorporating a physical pendulum.

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Leonard Klaus, Florian Beug und Thomas Bruns
Proc. of IMEKO TC3, TC5 and TC22 International Conference 2017
Helsinki, Finnland
2017

Zusammenfassung: Measurements of mechanical quantities are often carried out with transducers having a bridge output. These output signals are conditioned using bridge amplifiers. If dynamically changing quantities are going to be measured traceably, the bridge amplifier has to be calibrated dynamically.This paper describes a dynamic bridge amplifier calibration set-up based on the new PTB dynamic bridge standard. The calibration is carried out by synchronous sampling of the bridge amplifier output voltage and a reference signal provided by the calibrated dynamic bridge standard. The dynamic bridge standard enables calibrations in a frequency range from DC (static calibration) up to 10 kHz. An overview of the different measurement uncertainty contributions is given and the first measurement results show a good agreement with a previously established measurement set-up.

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