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H. Ecker:
"Exploring the Use of Parametric Excitation";
Keynote Lecture: 10th International Conference on Recent Advances in Structural Dynamics (RASD 2010), Southampton (invited); 2010-07-12 - 2010-07-14; in: "Proceedings RASD 2010", M. J. Brennan (ed.); (2010), 1 - 18.

In the past parametric excitation was considered almost exclusively to have only negative effects on the dynamics of systems. Therefore, the focus of research studies was mostly on how to avoid or at least minimize the adverse consequences of parametric excitation. Nevertheless, some attempts were also made to take advantage of the vibration amplification if a system operates at a parametric instability.

However, recent research results have also shown that parametric excitation may not only cause harmful instabilities in a dynamical system but can also improve the capability of a system to suppress vibrations. In particular it is possible to avoid the onset of an instability by introducing parametric excitation to the system. These findings are quite new and the numerous possibilities of making use of it still need to be explored and discussed.

In this article an overview on relevant research activities is given. The case of vibration suppression of a simple 2-mass system is discussed in detail with respect to the damping needed in the system to maintain stability although destabilizing forces are present. The potential of parametric vibration suppression is discussed and directions for further research and future practical applications are outlined.

Time-periodic stiffness variation, self-excitation, enhanced damping, stability