Active strongly nonlinear vibration absorbers - optimal configurations and performance exploration

Nonlinear vibration absorbers not only mitigate vibrations but also operate effectively over a wide frequency range [1]. This makes them particularly interesting for applications to civil engineering structures, where load characteristics change frequently and the properties of the structure itself are uncertain and vary over its long lifespan. Researchers extensively studied nonlinear absorbers, including systems with strong nonlinearity. They concluded that these absorbers unfold their potential only with optimal parameter sets, configured to the expected excitation, and if the input energy exceeds a threshold. To overcome these dependencies, we investigate optimal parameter configurations of a nonlinear absorber attached to a base structure under frequency and amplitude detuning of harmonic excitation. The numerical studies include single-mass and multi-mass base structures. From the set of optimal parameters, we derive parameter adaptation laws for key properties of the nonlinear absorber, providing a design basis for a (semi-)active device. To demonstrate the effectiveness of a (semi-) active nonlinear absorber for civil engineering applications, we apply practical (statistical) load cases to a base structure with realistic system parameters and dimensions, and compare the performance of the active nonlinear absorber with a conventional linear tuned mass damper. [1] A.F. Vakakis, O.V. Gendelmann, L.A. Bergman, D.M. McFarland, G.Kerschen, Y.S. Lee, Nonlinear Targeted Energy Transfer in Mechanical and Structural Systems, Springer (2008)