Optimum exciter placement for normal mode force appropriation

Wright, J.F.; Holmes, Paul; Desforges, M.J.; Cooper, Jonathan

doi:10.1243/0954410981532315

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…The advantage of the proposed method is the computational efficiency in a certain combination of positions because only eigenvalue operations of low dimensional matrices are involved in equation (15). Under the circumstance that the DOF of the structure is large, genetic algorithm 14 is suggested to search for the optimal combination of locations.…”

Section: Optimal Configuration Methodsmentioning

confidence: 99%

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Optimal configuration of shakers for phase resonance testing using modal parameters

Chen

Jin

Song

2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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The phase resonance testing is widely used in the ground vibration test for aircraft due to the advantages of distinguishing closely spaced modes and directly comparing normal mode shapes with those from finite element model. However, the process to configure the shakers is time-consuming. A method to configure the shakers, which calculates the appropriate force vector and estimates the optimal combination of excitation locations for phase resonance testing, is proposed in this paper. Compared with other configuration methods, where the frequency response function matrix is known a priori, the proposed method only requires a priori information of rough modal parameters. Therefore, less information is used in this method, which leads to the advantage of calculating the optimal configuration more efficiently. In this method, the modal force amplitude ratio of the target mode to all the modes, called the modal ratio indicator, is set up as the criterion to select the optimal configuration. Simulations of a discrete plate are performed to show the process of the method. An experiment of a steel beam is conducted to validate the effectiveness and reliability of this method.

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Section: Optimal Configuration Methodsmentioning

confidence: 99%

“…To perform the search for an optimal combination of excitation points, a genetic algorithm was used by Wright et al. 14 to replace the enumeration search.…”

Section: Introductionmentioning

confidence: 99%

Optimal configuration of shakers for phase resonance testing using modal parameters

Chen

Jin

Song

2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Several methods have been proposed [3,8,12,14] to describe the success of any combination of exciters in exciting any given modes.…”

Section: Optimal Excitationmentioning

confidence: 99%

“…Given a large number of possible exciter positions and a smaller number of exciters, it is beneficial to know which excitation positions, or combination of positions, will excite the required system modes best. Several methods have been proposed [3,8,12,14] to describe the success of any combination of exciters in exciting any given modes.…”

Section: Optimal Excitationmentioning

confidence: 99%

Force appropriation for flight flutter testing

Desforges

Cooper

Wright

2004

Proceedings of the Institution of Mechanical Engineers, Part G:

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In this paper, the multivariate mode indicator function (MMIF) method has been applied to simulated flutter test data in order to evaluate the potential application of normal mode force appropriation to flight flutter testing where there are many close modes and noise levels are severe. It is seen that the approach is capable of estimating accurate modal frequencies and force patterns from corrupted test data, for use in the appropriation of particular modes. Damping ratios are accurately estimated from a decay response following a resonance dwell. The complex mode indicator function (CMIF) has also been considered. The practical limitations of in-flight force appropriation are discussed, and the effects of the limited excitation possibilities are demonstrated by simulation. The number and position of exciters used are arguably the most important factors in determining the success of this technique. The application of force appropriation to flight flutter testing may well depend on the availability of small detachable vanes which allow direct excitation of all areas of the aircraft structure.

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