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A Generalised Multiple-Mass Based Method for the Determination of the Live Mass of a Force Transducer

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A Generalised Multiple-Mass Based Method for the Determination of the Live Mass of a Force Transducer. / Montalvao, Diogo; Baker, Thomas; Ihracska, Balazs; Aulaqi, Muhammad.

In: Mechanical Systems and Signal Processing, Vol. 83, 15.01.2017, p. 506-521.

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Montalvao, Diogo ; Baker, Thomas ; Ihracska, Balazs ; Aulaqi, Muhammad. / A Generalised Multiple-Mass Based Method for the Determination of the Live Mass of a Force Transducer. In: Mechanical Systems and Signal Processing. 2017 ; Vol. 83. pp. 506-521.

Bibtex

@article{c7a477e4363e4eaa8f5069e7f93bb721,
title = "A Generalised Multiple-Mass Based Method for the Determination of the Live Mass of a Force Transducer",
abstract = "Many applications in Experimental Modal Analysis (EMA) require that the sensors{\textquoteright} masses are known. This is because the added mass from sensors will affect the structural mode shapes, and in particular its natural frequencies. EMA requires the measurement of the exciting forces at given coordinates, which is often made using piezoelectric force transducers. In such a case, the live mass of the force transducer, i.e. the mass as {\textquoteleft}seen{\textquoteright} by the structure in perpendicular directions must be measured somehow, so that compensation methods like mass cancelation can be performed. This however presents a problem on how to obtain an accurate measurement for the live mass. If the system is perfectly calibrated, then a reasonably accurate estimate can be made using a straightforward method available in most classical textbooks based on Newton{\textquoteright}s second law. However, this is often not the case (for example when the transducer{\textquoteright}s sensitivity changed over time, when it is unknown or when the connection influences the transmission of the force). In a self-calibrating iterative method, both the live mass and calibration factor are determined, but this paper shows that the problem may be ill-conditioned, producing misleading results if certain conditions are not met. Therefore, a more robust method is presented and discussed in this paper, reducing the ill-conditioning problems and the need to know the calibration factors beforehand. The three methods will be compared and discussed through numerical and experimental examples, showing that classical EMA still is a field of research that deserves the attention from scientists and engineers.",
keywords = "experimental modal analysis, force transducer, calibration, live mass",
author = "Diogo Montalvao and Thomas Baker and Balazs Ihracska and Muhammad Aulaqi",
note = "{\textcopyright} 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).",
year = "2017",
month = jan,
day = "15",
doi = "10.1016/j.ymssp.2016.06.028",
language = "English",
volume = "83",
pages = "506--521",
journal = "Mechanical Systems and Signal Processing",
issn = "0888-3270",
publisher = "Academic Press Inc.",

}

RIS

TY - JOUR

T1 - A Generalised Multiple-Mass Based Method for the Determination of the Live Mass of a Force Transducer

AU - Montalvao, Diogo

AU - Baker, Thomas

AU - Ihracska, Balazs

AU - Aulaqi, Muhammad

N1 - © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

PY - 2017/1/15

Y1 - 2017/1/15

N2 - Many applications in Experimental Modal Analysis (EMA) require that the sensors’ masses are known. This is because the added mass from sensors will affect the structural mode shapes, and in particular its natural frequencies. EMA requires the measurement of the exciting forces at given coordinates, which is often made using piezoelectric force transducers. In such a case, the live mass of the force transducer, i.e. the mass as ‘seen’ by the structure in perpendicular directions must be measured somehow, so that compensation methods like mass cancelation can be performed. This however presents a problem on how to obtain an accurate measurement for the live mass. If the system is perfectly calibrated, then a reasonably accurate estimate can be made using a straightforward method available in most classical textbooks based on Newton’s second law. However, this is often not the case (for example when the transducer’s sensitivity changed over time, when it is unknown or when the connection influences the transmission of the force). In a self-calibrating iterative method, both the live mass and calibration factor are determined, but this paper shows that the problem may be ill-conditioned, producing misleading results if certain conditions are not met. Therefore, a more robust method is presented and discussed in this paper, reducing the ill-conditioning problems and the need to know the calibration factors beforehand. The three methods will be compared and discussed through numerical and experimental examples, showing that classical EMA still is a field of research that deserves the attention from scientists and engineers.

AB - Many applications in Experimental Modal Analysis (EMA) require that the sensors’ masses are known. This is because the added mass from sensors will affect the structural mode shapes, and in particular its natural frequencies. EMA requires the measurement of the exciting forces at given coordinates, which is often made using piezoelectric force transducers. In such a case, the live mass of the force transducer, i.e. the mass as ‘seen’ by the structure in perpendicular directions must be measured somehow, so that compensation methods like mass cancelation can be performed. This however presents a problem on how to obtain an accurate measurement for the live mass. If the system is perfectly calibrated, then a reasonably accurate estimate can be made using a straightforward method available in most classical textbooks based on Newton’s second law. However, this is often not the case (for example when the transducer’s sensitivity changed over time, when it is unknown or when the connection influences the transmission of the force). In a self-calibrating iterative method, both the live mass and calibration factor are determined, but this paper shows that the problem may be ill-conditioned, producing misleading results if certain conditions are not met. Therefore, a more robust method is presented and discussed in this paper, reducing the ill-conditioning problems and the need to know the calibration factors beforehand. The three methods will be compared and discussed through numerical and experimental examples, showing that classical EMA still is a field of research that deserves the attention from scientists and engineers.

KW - experimental modal analysis

KW - force transducer

KW - calibration

KW - live mass

U2 - 10.1016/j.ymssp.2016.06.028

DO - 10.1016/j.ymssp.2016.06.028

M3 - Article

VL - 83

SP - 506

EP - 521

JO - Mechanical Systems and Signal Processing

JF - Mechanical Systems and Signal Processing

SN - 0888-3270

ER -