Linear viscoelastic vibration absorbers (VA) exhibit a number of drawbacks such as global detuning in damping due to thermal effects, high levels of strokes, requirement of significant mass ratios for good performances in attenuation. To increase the performance of VAs, nonlinearities in either the stiffness or damping have been purposely introduced in the absorbers (e.g., Roberson [1]; Snowdon [2]). Besides the advantages, however, the presence of nonlinearities introduces dynamic instabilities which can arise if damping is weak, resulting in large-amplitude quasiperiodic or chaotic vibrations. In engineering practice, nonlinear VAs exploiting friction between structural parts have been investigated by studying their optimum parameters under harmonic and white-noise excitations. It has been shown that the friction VA tends to be more effective than a linear viscoelastic VA as the amplitude of the excitation becomes large. Attractive technical possibilities are offered by the exploitation of hysteresis [3, 4] that is developed in traditional materials or elements, such as in wire ropes or flexural cables, or in new smart materials such as shape memory alloys [5] by which enhancement in the absorber damping and tuning properties can be achieved along with a simplification in terms of construction and maintenance, and improved thermal stability. Recent efforts are targeted towards properly engineered nanostructured materials made of carbon nanotubes where high levels of hysteresis are developed at the nano/micro-structural level (Formica et al. [6]). In the present work, the performance of a new vibration absorber based on macro-structural hysteresis is studied both theoretically and experimentally. The VA exploits the hysteresis exhibited by wire ropes and flexural cables under cyclic loadings. The proposed hysteretic vibration absorbers allow to overcome some of the known drawbacks, especially the general device stability and performance yet greatly simplifying the device design and its engineering.
Hysteresis-based nonlinear vibration absorbers / Carpineto, N; Lacarbonara, Walter; Vestroni, F.. - ELETTRONICO. - (2010), pp. 1-2. (Intervento presentato al convegno Thirteenth Conference on Nonlinear Vibrations, Dynamics, and Mulitbody Systems tenutosi a Virginia Tech, Blacksburg, VA, USA nel 23-27 maggio 2010).
Hysteresis-based nonlinear vibration absorbers
LACARBONARA, Walter;
2010
Abstract
Linear viscoelastic vibration absorbers (VA) exhibit a number of drawbacks such as global detuning in damping due to thermal effects, high levels of strokes, requirement of significant mass ratios for good performances in attenuation. To increase the performance of VAs, nonlinearities in either the stiffness or damping have been purposely introduced in the absorbers (e.g., Roberson [1]; Snowdon [2]). Besides the advantages, however, the presence of nonlinearities introduces dynamic instabilities which can arise if damping is weak, resulting in large-amplitude quasiperiodic or chaotic vibrations. In engineering practice, nonlinear VAs exploiting friction between structural parts have been investigated by studying their optimum parameters under harmonic and white-noise excitations. It has been shown that the friction VA tends to be more effective than a linear viscoelastic VA as the amplitude of the excitation becomes large. Attractive technical possibilities are offered by the exploitation of hysteresis [3, 4] that is developed in traditional materials or elements, such as in wire ropes or flexural cables, or in new smart materials such as shape memory alloys [5] by which enhancement in the absorber damping and tuning properties can be achieved along with a simplification in terms of construction and maintenance, and improved thermal stability. Recent efforts are targeted towards properly engineered nanostructured materials made of carbon nanotubes where high levels of hysteresis are developed at the nano/micro-structural level (Formica et al. [6]). In the present work, the performance of a new vibration absorber based on macro-structural hysteresis is studied both theoretically and experimentally. The VA exploits the hysteresis exhibited by wire ropes and flexural cables under cyclic loadings. The proposed hysteretic vibration absorbers allow to overcome some of the known drawbacks, especially the general device stability and performance yet greatly simplifying the device design and its engineering.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
