Optimal configuration of shakers for phase resonance testing using modal parameters

Abstract

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.

Keywords

Phase resonance testing optimal combination appropriate force vector closely spaced mode modal parameter

Get full access to this article

View all access options for this article.

References

Otte D, Van der Auweraer H, Debille J, et al. Enhanced force vector appropriation methods for normal mode testing. In: Proceedings of the 17th international seminar on modal analysis, Leuven, Belgium, 1992, pp.643–658.

Shahdin

Morlier

Gourinat

. Damage monitoring in sandwich beams by modal parameter shifts: a comparative study of burst random and sine dwell vibration testing. J Sound Vib 2010; 329: 566–584.

Ehrhardt

Allen

. Measurement of nonlinear normal modes using multi-harmonic stepped force appropriation and free decay. Mech Syst Signal Process 2016; s 76–77: 612–633.

Peeters

Climent

, et al. Modern solutions for ground vibration testing of large aircraft. J Sound Vib 2009; 43: 4–7.

Gloth G, Degener M and Füllekrug U. Experimental investigation of new GVT concepts for large aircraft. In: Proceedings of IMAC 19: international modal analysis conference, Kissimmee, FL, USA, vol. 35, 2001 pp.14-18.

Böswald M, Göge D, Füllekrug U, et al. A review of experimental modal analysis methods with respect to their applicability to test data of large aircraft structures. In: ISMA 2006 - international conference on noise & vibration engineering, Everlee, Belgium, 2006, pp.2461–2481.

Torre

ODL

Escaler

Egusquiza

, et al. Experimental mode shape determination of a cantilevered hydrofoil under different flow conditions. Proc IMechE, Part C: J Mechanical Engineering Science 2017; 142: S–921.

Girolamo P. Selection and evaluation of optimum exciter locations for modal testing via automated acceleration transfer function analysis. In: 25th structures, structural dynamics and materials conference, Alm Springs, USA, 1984, pp.23–38.

Niedbal N and Klusowski E. Optimal exciter placement and force vector tuning required for experimental modal analysis. In: Dynamics specialists conference, Long Beach, USA, 1990, p.1205.

10.

Morosow

Ayre

. Force apportioning for modal vibration testing using incomplete excitation. Sound Vib Bull 1978; 48: 39–48.

11.

Williams R, Crowley J and Vold H. The multivariate mode indicator function in modal analysis. In: Proceedings of the 3rd International Modal Analysis Conference, Orlando, USA, 1986, pp.66–70.

12.

Juang

J-N

Wright

. A multi-point force appropriation method based upon a singular value decomposition approach. J Vib Acoust 1991; 113: 176–181.

13.

Niedbal N and Klusowski E. Optimal exciter placement and force vector tuning required for experimental modal analysis. In: ESA SP-321 (volume 1), Spacecraft structures and mechanical testing, proceedings of the international conference held at ESTEC, Noordwijk, Netherlands, 1990, pp.463–473.

14.

Wright

Holmes

Desforges

, et al. Optimum exciter placement for normal mode force appropriation. Proc IMechE, Part G: J Aerospace Engineering 1998; 212: 325–338.

15.

Kientzy

Richardson

Blakely

. Using finite element data to set up modal tests. Sound Vib Mag 1989; 23: 16–19.

16.

Wright

Cooper

Desforges

. Normal-mode force appropriation—theory and application. Mech Syst Signal Process 1999; 13: 217–240.

17.

Bucher

Braun

. Left eigenvectors: extraction from measurements and physical interpretation. J Appl Mech 1997; 64: 97–105.

18.

Ibáñez

. Force appropriation by extended Asher's method. SAE Technical Paper. Report no. 0148-7191, 1976.

19.

Peeters

Herman

VDA

Guillaume

, et al.

The PolyMAX frequency-domain method: a new standard for modal parameter estimation?

Shock Vib 2004; 11: 395–409.