Rigid Body and Nonlinear Mount Identification : Application to Onboard Equipment With Hysteretic Suspension

Abstract

This article describes a step-by-step procedure for improving the dynamic behavior of a rigid body mounted on a linear flexible structure with nonlinear hysteretic suspension. Special attention is paid to the inertia property identification carried out with an original experimental technique. The hysteretic suspen sion parameters are measured with a specific device. Condensation and modal methods permit reducing the number of equations of the finite element model of the structure with localized nonlinearities. The technique (numerical and experimental) is applied to an onboard camera that, under real operating conditions, is carried externally on a helicopter. As the model is validated by experiments, the simulated modification, which better reduces the vibration level of the camera, is retained. The new assembly has been designed and successfully tested.

Keywords

Key Words: Inertia properties hysteretic suspension identification onboard equipment

Get full access to this article

View all access options for this article.

References

Butsuen, T. , Ookuma, M. , and Nagamatsu, A. , 1986, "Application of direct system identification method for engine rigid body mount system," SAE Paper No. 860551.

Conti, P. and Bretl, J. , 1989, "Mount stiffnesses and inertia properties from modal test data," ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design 111, 134-139.

Dufour, R. , Gjika, K. , and Pompéi, M. , 1992, "Dynamic behavior of flexible structures mounted on non-linear passive suspensions: Prediction and experiments," Revue Mécanique Industrielle et Matériaux 444, 38-40.

Gjika, K. , Dufour, R. , and Ferraris, G. , 1996, "Transient response of structures on viscoelastic or elastoplastic mounts: Prediction and experiment," Journal of Sound and Vibration 198(3), 361-377.

Ko, J.M. , Ni, Y.Q. , and Tian, Q.L. , 1992, "Hysteretic behavior and empirical modeling of a wire-cable vibration isolator," International Journal of Analytical and Experimental Modal Analysis 7(2), 111-127.

Nashif, A.D. , Jones, D.I.G. , and Handerson, J.P. , 1985, Vibration Damping, John Wiley , New York.

Pandit, S.M. and Hu, Z.Q. , 1994, "Determination of rigid body characteristics from time domain modal test data," Journal of Sound and Vibration 177(1), 31-41.

Swider, P. , 1991, "Procédé et dispositif pour la determination des caractéristiques d'inertie d'un corps solide," Brevet d'Invention (French Patent) 9313221, INSA de Lyon.

Wong, C.W. , Ni, Y.Q. , and Ko, J.M. , 1993, "Steady state dynamic response of structures with non-linear hysteretic isolators," International Journal of Analytical and Experimental Modal Analysis 8(1), 63-78.