Floor and Facility Vibration Mitigation Using Passive and Hybrid Nonlinear Energy Sinks

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Floor and Facility Vibration Mitigation Using Passive and Hybrid Nonlinear Energy Sinks, CMS proposal 0344433 PI: L. A. Bergman, UIUC The proposal explores the use of a novel nonlinear energy sink (NES) in a passive or hybrid isolation and control system in order to mitigate floor and facility vibrations. Recent investigations have verified that the presence of an essentially nonlinear oscillator weakly coupled to a linear oscillator can induce the phenomenon of energy pumping from the linear to the nonlinear system. More specifically, transient vibrations in the directly excited linear system were shown, under certain conditions, to be transmitted out of the linear system and into the nonlinear one in a one-way, irreversible fashion. This energy pumping phenomenon was found to be robust and quite rapid, making it an excellent candidate for an efficient vibration mitigation system. The work proposed herein would investigate the application of this nonlinear energy sink concept to vibration isolation and control in high-precision technology situations, studying various strategies for passive and/or hybrid vibration isolation, quantifying its performance, and exploring new approaches for improving energy transfer. New educational prospects in structural control would also be developed as part of this work, exposing more students to a vital new field of structural engineering research and design. Intellectual Merit: Major thrusts are proposed as follows: To determine the practicality of NES for vibration isolation, a thorough investigation of the theory of energy pumping and the design and analysis of nonlinear energy sinks is planned. To meet these needs, we will pursue extension of nonlinear energy sink theory, modeling and simulation of nonlinear energy sinks in high-precision technology applications, experimental verification of NES performance, and exploration of mechanisms for enhancing energy pumping. In addition, this project has the overall goal of creating new educational opportunities in the field of structural dynamics and control. This will be accomplished through the involvement of undergraduate students in research (recruited through formal and informal programs at each PI.s institution) and the creation of courses and course materials for graduate student classes. Also, the needs of current professionals will be addressed via greater access to educational material through distance Learning, multimedia presentations, and other electronic communication technologies. Broader Impacts: The research and educational activities outlined in this proposal represent an examination of a fundamentally new approach to the problem of isolating microvibrations in precision Environments. The use of resonance capture in coupled oscillator systems to induce energy pumping provides a simple means for transferring and eliminating unwanted vibrations that does not rely upon large actuator forces or complex control schemes. The proposed work will not only provide verification of the practicality of this approach to structural control, but it will also improve and extend our understanding of the underlying phenomena, permitting advances towards even more efficient systems. The existence of well-established facilities at each PI's institution will permit the construction of laboratory and numerical simulations in active working environments, supplying sufficient resources for the research activities. In addition, all of the institutions participating in this proposal have highly developed recruiting programs and instructional support centers, helping the PIs to realize their proposed educational functions in a straightforward way. The educational components of the proposed work will promote teaching, training, and learning through the efforts to recruit undergraduate students as researchers and to create research-based materials that will be incorporated into classroom lectures. In addition, learning opportunities for graduate students will be generated through both the traditional research participation as well as the forming of new courses in structural control. The infrastructure for research and education will be enhanced through the development of educational multimedia materials that will be used to promote continuing education in the field of structural control. This will also provide a means for broad dissemination of pertinent scientific and technological information to practitioners who are facing retrofitting and/or design of high-precision technology facilities.