A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing

As an alternative to operational modal analysis and classical experimental modal analysis (EMA), a novel method was introduced previously, namely impact-synchronous modal analysis (ISMA). The effectiveness ISMA on rotor and structural dynamic systems has been proven in previous literature. More rece...

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Main Authors: Lim, Hong Cheet, Ong, Zhi Chao, Ismail, Zubaidah, Khoo, Shin Yee
Format: Article
Published: American Society of Mechanical Engineers (ASME) 2018
Subjects:
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author Lim, Hong Cheet
Ong, Zhi Chao
Ismail, Zubaidah
Khoo, Shin Yee
author_facet Lim, Hong Cheet
Ong, Zhi Chao
Ismail, Zubaidah
Khoo, Shin Yee
author_sort Lim, Hong Cheet
collection UM
description As an alternative to operational modal analysis and classical experimental modal analysis (EMA), a novel method was introduced previously, namely impact-synchronous modal analysis (ISMA). The effectiveness ISMA on rotor and structural dynamic systems has been proven in previous literature. More recently, an automated impact device (AID) was introduced which utilized tachometer pulse as initiation signal and its effectiveness on ISMA was proven. An attempt to further enhance this device in term of equipment and cost is then proposed by replacing the tachometer with the in-use tri-axial accelerometer through utilizing the filtered response of cyclic load component as an initiation signal to control the impact device, which is also the primary aim for this study. Prior to modal testing, accuracy of this device is illustrated at desired phase angles of 0 deg, 90 deg, 180 deg, and 270 deg. Subsequently, frequency response function (FRF) estimations obtained for ISMA using enhanced AID has demonstrated the suppression capabilities of this device on disturbances, i.e., reduction of 93.58% at 30 Hz and 57.78% at 60 Hz, resulting in a high correlation for signature assurance criterion (SAC) and cross signature assurance criterion (CSAC). Modal parameters extracted from the EMA and ISMA using impact device are presented and compared, for the first three natural modes of the test rig. It is found that natural frequencies are deviating by less than 6%, whereas modal assurance criterion (MAC) values between the mode shapes of the two tests are found to be above 0.9.
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spelling um.eprints-200382019-01-17T03:30:37Z http://eprints.um.edu.my/20038/ A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing Lim, Hong Cheet Ong, Zhi Chao Ismail, Zubaidah Khoo, Shin Yee TA Engineering (General). Civil engineering (General) TJ Mechanical engineering and machinery As an alternative to operational modal analysis and classical experimental modal analysis (EMA), a novel method was introduced previously, namely impact-synchronous modal analysis (ISMA). The effectiveness ISMA on rotor and structural dynamic systems has been proven in previous literature. More recently, an automated impact device (AID) was introduced which utilized tachometer pulse as initiation signal and its effectiveness on ISMA was proven. An attempt to further enhance this device in term of equipment and cost is then proposed by replacing the tachometer with the in-use tri-axial accelerometer through utilizing the filtered response of cyclic load component as an initiation signal to control the impact device, which is also the primary aim for this study. Prior to modal testing, accuracy of this device is illustrated at desired phase angles of 0 deg, 90 deg, 180 deg, and 270 deg. Subsequently, frequency response function (FRF) estimations obtained for ISMA using enhanced AID has demonstrated the suppression capabilities of this device on disturbances, i.e., reduction of 93.58% at 30 Hz and 57.78% at 60 Hz, resulting in a high correlation for signature assurance criterion (SAC) and cross signature assurance criterion (CSAC). Modal parameters extracted from the EMA and ISMA using impact device are presented and compared, for the first three natural modes of the test rig. It is found that natural frequencies are deviating by less than 6%, whereas modal assurance criterion (MAC) values between the mode shapes of the two tests are found to be above 0.9. American Society of Mechanical Engineers (ASME) 2018 Article PeerReviewed Lim, Hong Cheet and Ong, Zhi Chao and Ismail, Zubaidah and Khoo, Shin Yee (2018) A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing. Journal of Dynamic Systems, Measurement, and Control, 141 (3). 034501. ISSN 0022-0434, DOI https://doi.org/10.1115/1.4041609 <https://doi.org/10.1115/1.4041609>. https://doi.org/10.1115/1.4041609 doi:10.1115/1.4041609
spellingShingle TA Engineering (General). Civil engineering (General)
TJ Mechanical engineering and machinery
Lim, Hong Cheet
Ong, Zhi Chao
Ismail, Zubaidah
Khoo, Shin Yee
A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title_full A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title_fullStr A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title_full_unstemmed A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title_short A Performance Study of Controlled Impact Timing on Harmonics Reduction in Operational Modal Testing
title_sort performance study of controlled impact timing on harmonics reduction in operational modal testing
topic TA Engineering (General). Civil engineering (General)
TJ Mechanical engineering and machinery
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