Modal parameter estimation from base excitation

Béliveau, Jean-Guy; Vigneron, F. R.; Soucy, Y.; Draisey, Sherry

doi:10.1016/s0022-460x(86)80117-1

Cited by 41 publications

(20 citation statements)

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“…Additionally, during the accelerated fatigue test the changes to the modal parameters of the specimen occur [6] and [7], which consequently alter the specimen's response and must also be taken into the account in theoretical discussion. The following discussion is applied to the basic outline of the accelerated vibration fatigue experiment, illustrated in Fig.…”

Section: Specimen's Dynamic Response To the Harmonic Excitationmentioning

confidence: 99%

Vibrational Fatigue and Structural Dynamics for Harmonic and Random Loads

Česnik

Slavič

2015

SV-JME

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Section: Specimen's Dynamic Response To the Harmonic Excitationmentioning

confidence: 99%

Vibrational Fatigue and Structural Dynamics for Harmonic and Random Loads

Česnik

Slavič

2015

SV-JME

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“…(1) Besides, the relative error of the first order natural frequency is 1.93%, the relative errors of the other order natural frequencies are less than 1%. (2) The relative errors of the damping ratios are less than 10% except for the first-and fourth-order damping ratios which have the relative errors about 40%. (3) The modal shapes of the fixed FRF and the ATF are essentially coincident with each other.…”

Section: Experimental Verificationmentioning

confidence: 94%

“…(1) The relative errors of each order natural frequencies are less than 1.7%. (2) The relative errors of the damping ratios are less than 27%. (3) The modal shapes of the free FRF and the IFTF at each mode are in good agreement.…”

Section: Experimental Verificationmentioning

confidence: 96%

“…Hence, the acceleration transfer function (ATF) is primarily used to identify the fixed modal parameters of the test article. Be´liveau et al 2 obtains the formula of the ATF that equals the product of the FRF and the mass matrix and the constrained modal vector. So the fixed modal parameters, such as natural frequency, damping ratio and mode shape, can be identified correspondingly.…”

Section: Introductionmentioning

confidence: 99%

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Modal parameter identification of structure under base excitation using vibration test data

Xia

Song

2016

Proceedings of the Institution of Mechanical Engineers, Part G:

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In the active flight phase, the spacecraft suffers the rigorous external vibration environment which comes from the engine at the bottom of rocket. In course of the ground test, the shaker simulates such excitation through the base movement, and the modal parameters identification method which employs the vibration test data is to the more extent in line with the operating state. In this paper, a specified method is applied for parameter estimation of lumped-mass mechanical system in the vibration test. The modal parameters under the fixed and free-free constrained state can be identified at the same time by this technique. In addition, when the analytical model which includes the test article and the shaking table is adopted, the relations between the response transfer function (RTF) and frequency response function (FRF) are clarified, and some misconceptions in the engineering practice are cleared. Because of the uncertain of the connection impedance between the test article and the shaking table, only the partial parameters of the fixed mode can be identified, such as natural frequency, modal damping ratio and modal shape. As the interface force transfer function (IFTF) can eliminate the influence of the connection impedance and the fixed impedance matrix of the test piece is transformed into the free impedance matrix, the identified parameters of the free mode are complete. Furthermore, the influence of the constraint degree of freedom (DOF) on the parameter identification of the IFTF is discussed preliminarily. Finally, the numerical simulation and the vibration test of discrete structure verify the validity of the proposed method.

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“…The measurable quantities upon which parameter estimation is based are 1) the input acceleration a Q (t) equal to 2(0 and 2) the inertial accelerations at each mass point denoted by (a x (t) 9 a y (t),a z (t)} 9 where t denotes time, an independent variable. The analytical model of this test configuration can be described in the frequency domain by where 3Tl£ x are "modal identity parameters" defined by /CO -\k (4) Estimates of \ k , Q k , and ® xk can be derived from tests as outlined in the foregoing, and from them measurement-based estimates for 9H^ can be calculated using Eq. (4); 31^ is a measure of the net linear momentum associated with the kth vibratory mode and also is invariant to the choice of modal normalization constant of $ k .…”

Section: Estimation Concepts and Proceduresmentioning

confidence: 99%

Experimental identification of modal momentum coefficients and modalidentity parameters

1989

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The identification from laboratory test data of modal momentum coefficients, modal identity parameters, and conventional modal parameters (frequencies, damping factors, mode shapes, and modal normalization constants) is successfully demonstrated using recently developed theoretical procedures that are based on driven-base and portable exciter modal tests. The tests and demonstration employ a cantilever beam with unidirectional driven-base excitation. The use of experiment-derived modal parameters with modal identities to obtain a measurement-based assessment of relative modal momenta and completeness of the modal determination also is demonstrated. The results of three independent sets of data are compared with each other and with corresponding theoretical results for an undamped uniform cantilever beam.

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Modal parameter estimation from base excitation

Cited by 41 publications

References 1 publication

Vibrational Fatigue and Structural Dynamics for Harmonic and Random Loads

Vibrational Fatigue and Structural Dynamics for Harmonic and Random Loads

Modal parameter identification of structure under base excitation using vibration test data

Experimental identification of modal momentum coefficients and modalidentity parameters

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