Experimental testing of Timoshenko predictions of supercritical natural frequencies and mode shapes for free-free beams

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

Standard

Experimental testing of Timoshenko predictions of supercritical natural frequencies and mode shapes for free-free beams. / Brøns, Marie; Thomsen, Jon Juel.

In: Journal of Sound and Vibration, Vol. 459, 114856, 2019.

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

Harvard

APA

CBE

MLA

Vancouver

Author

Bibtex

@article{8434ebf1298846e7a2790dfc6dbca625,
title = "Experimental testing of Timoshenko predictions of supercritical natural frequencies and mode shapes for free-free beams",
abstract = "In this experimental work a scanning laser Doppler vibrometer is used to measure mode shapes and natural frequencies of beam bending vibrations above the critical frequency predicted by Timoshenko theory. Above the critical frequency the mode shapes are intricate, so to quantitative compare theoretical and experimental mode shapes, the modal assurance criterion (MAC) is applied. This reveals that the order of the modes is not as theory predicts, and that other plane modes can easily be misinterpreted as bending modes. This can lead to an incorrect comparison of natural frequencies. With the MAC tool it is found that the correlation between theoretical mode shapes and measured mode shapes is very high; It can be concluded that supercritical Timoshenko-predicted mode shapes agrees well with the experimentally observed modes, and the supercritical natural frequencies deviate from Timoshenko theory within five percent. Comparisons are made to other studies, and against a numerical 3D model.",
keywords = "Critical frequency, Modal assurance criterion, Mode shapes, Rotary inertia, Scanning laser Doppler vibrometry, Shear bending, Timoshenko beam theory, Timoshenko frequency pairs",
author = "Marie Br{\o}ns and Thomsen, {Jon Juel}",
year = "2019",
doi = "10.1016/j.jsv.2019.114856",
language = "English",
volume = "459",
journal = "Journal of Sound and Vibration",
issn = "0022-460X",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Experimental testing of Timoshenko predictions of supercritical natural frequencies and mode shapes for free-free beams

AU - Brøns, Marie

AU - Thomsen, Jon Juel

PY - 2019

Y1 - 2019

N2 - In this experimental work a scanning laser Doppler vibrometer is used to measure mode shapes and natural frequencies of beam bending vibrations above the critical frequency predicted by Timoshenko theory. Above the critical frequency the mode shapes are intricate, so to quantitative compare theoretical and experimental mode shapes, the modal assurance criterion (MAC) is applied. This reveals that the order of the modes is not as theory predicts, and that other plane modes can easily be misinterpreted as bending modes. This can lead to an incorrect comparison of natural frequencies. With the MAC tool it is found that the correlation between theoretical mode shapes and measured mode shapes is very high; It can be concluded that supercritical Timoshenko-predicted mode shapes agrees well with the experimentally observed modes, and the supercritical natural frequencies deviate from Timoshenko theory within five percent. Comparisons are made to other studies, and against a numerical 3D model.

AB - In this experimental work a scanning laser Doppler vibrometer is used to measure mode shapes and natural frequencies of beam bending vibrations above the critical frequency predicted by Timoshenko theory. Above the critical frequency the mode shapes are intricate, so to quantitative compare theoretical and experimental mode shapes, the modal assurance criterion (MAC) is applied. This reveals that the order of the modes is not as theory predicts, and that other plane modes can easily be misinterpreted as bending modes. This can lead to an incorrect comparison of natural frequencies. With the MAC tool it is found that the correlation between theoretical mode shapes and measured mode shapes is very high; It can be concluded that supercritical Timoshenko-predicted mode shapes agrees well with the experimentally observed modes, and the supercritical natural frequencies deviate from Timoshenko theory within five percent. Comparisons are made to other studies, and against a numerical 3D model.

KW - Critical frequency

KW - Modal assurance criterion

KW - Mode shapes

KW - Rotary inertia

KW - Scanning laser Doppler vibrometry

KW - Shear bending

KW - Timoshenko beam theory

KW - Timoshenko frequency pairs

U2 - 10.1016/j.jsv.2019.114856

DO - 10.1016/j.jsv.2019.114856

M3 - Journal article

VL - 459

JO - Journal of Sound and Vibration

JF - Journal of Sound and Vibration

SN - 0022-460X

M1 - 114856

ER -