Challenging an experimental nonlinear modal analysis method with a new strongly friction-damped structure
arXiv:2011.08527 · doi:10.1016/j.jsv.2020.115580
Abstract
In this work, we show that a recently proposed method for experimental nonlinear modal analysis based on the extended periodic motion concept is well suited to extract modal properties for strongly nonlinear systems (i.e. in the presence of large frequency shifts, high and nonlinear damping, changes of the mode shape, and higher harmonics). To this end, we design a new test rig that exhibits a large extent of friction-induced damping (modal damping ratio up to 15 %) and frequency shift by 36 %. The specimen, called RubBeR, is a cantilevered beam under the influence of dry friction, ranging from full stick to mainly sliding. With the specimen's design, the measurements are well repeatable for a system subjected to dry frictional force. Then, we apply the method to the specimen and show that single-point excitation is sufficient to track the modal properties even though the deflection shape changes with amplitude. Computed frequency responses using a single nonlinear-modal oscillator with the identified modal properties agree well with measured reference curves of different excitation levels, indicating the modal properties' significance and accuracy.
The final version of this article is available online at http://doi.org/10.1016/j.jsv.2020.115580
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Cited by in corpus (5)
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- Tracking Superharmonic Resonances for Nonlinear Vibration of Conservative and Hysteretic Single Degree of Freedom Systems
- Efficient Model Reduction and Prediction of Superharmonic Resonances in Frictional and Hysteretic Systems