The importance of avoiding or suppressing vibration is a universal concern that can hardly be overstated. Vibration may be damaging, annoying, or dangerous, and is a problem occurring in a vast array of situations ranging from suspension systems for vehicles to protective packaging to infrastructure hazard mitigation during earthquakes. The objective of the research described in this proposal is to develop a new class of vibration isolator based on elastically-buckled structures. Analytical, numerical, and experimental methods will be used together with a variety of test strategies and components to identify optimal approaches to vibration isolation. The results of this research will allow a generally undesirable effect (buckling) to be utilized in a beneficial context (vibration isolation). The proposed isolators are post-buckled rigid-link mechanisms, struts, and plates. They will be designed to have a high axial stiffness under static loading, so that they support the weight of the system without excessive displacement, and to have a relatively-low stiffness during excitation. Harmonic, multi-frequency, shock, impact, and random inputs will be considered, along with combinations of these. The isolator may protect the system from base excitation (e.g., in an earthquake), or may reduce the transmissibility of forces from the system (e,g., rotating machinery) to the base. These passive isolators may be used in conjunction with dampers and with semi-active or active control systems. The optimum properties, locations, and number of isolators will be determined. The intellectual merit of this approach includes a bridge between instability and structural dynamics. This type of cross-fertilization of ideas is exactly the type of activity that has enabled interdisciplinary research to be so successful. Both the analytical/numerical work and the experimental work contain significant challenges. The potential broader impacts of this approach are profound. Noise reduction, stealth technology, and flutter suppression in aircraft are just some of the directions in which this work could evolve. Distributed mounting options for shock absorption, and high-cycle fatigue mitigation, are clearly achievable goals. This is a collaborative proposal between Duke University and Virginia Tech. Each institution will benefit from enhanced interaction. The proximity of the two universities and previous collaborative work of the Principle Investigators provides a team whose sum is greater than the individual components. Underrepresented graduate and undergraduate students will be sought, and the results of this research will be disseminated broadly.
