9624949 Gavin The primary goal of this career research program is to develop a control system for seismic structural vibration suppression which is simple to implement, robust to uncertainties in the structural model, requires very little external power, and has guaranteed closed loop stability. Structural members with adjustable stiffness and damping will be installed in a lumped parameter structural system to achieve this goal. These members will make use of electrorheological (ER) and magnetorheological (MR) materials. These materials behave like Newtonian fluids in the absence of external electrostatic or magnetic fields but quickly become visco-electic plastic solids when strong fields are applied. A model for the controllable structural members will include a detailed model for ER and MR behavior at low shear rates. Experiments on ER and MR devices will be used to refine the analytical models. Models of a structure with interacting ER or MR devices will be used to derive control rules to suppress vibrations in these nonlinear systems. The performance of the control will be judged by the attenuation of deformations and absolute accelerations. Control synthesis will be carried out by using various control methods. The companion educational program is designed to capture the interest of young students to give them the opportunity to indulge their academic curiosities and to prepare graduate students for a productive career in structural control. A lecture and portable hands-on demonstration will be prepared to be delivered at area high schools and elementary schools. Powerful problem solving tools will be given to undergraduates computer packages. Undergraduates will have opportunities to conduct research of their own choosing or as part of this research program. Facilities will be in place to provide laboratory support to their projects. Graduate students will profit from a cummiculum in control that is coordinated across all engineering departm ents at Duke University. Local industries will be involved in both the research and education programs through collaborations and summer internships. This is a FY 96 Career award. ***
