modal testing; free-play; non-linear resonant decay method; identification of non-linearties
Abstract :
[en] Structural non-linearities are becoming of increasing importance in determining the performance of a range
of vibrating mechanical structures. As a consequence, the identification of systems with non-linearities is
starting to become a necessary part of vibration testing procedures. NL-RDM (Non-Linear Resonant Decay
Method) is an approach for the identification of non-linear multi-degree of freedom systems in modal
space on a mode by mode basis, using an appropriated sine excitation to isolate modes or groups of modes.
However, the application of NL-RDM to a multi-degree of freedom system with a discontinuous free-play
non-linearity has not been attempted yet, except to treat it using high order polynomial terms. The difficulty
of using NL-RDM when seeking a discontinuous free-play model lies in the choice of the so-called underlying
linear model to be used in uncoupling the linear equations. In this paper, a simulated two degree of
freedom lumped parameter system with a free-play non-linearity
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