This Career award emphasizes the development of tools for modeling identification, and response of mechanical systems that include dynamical dry friction. Typical examples of such systems include automobile squeak, rail-wheel squeal, metal cutting processes, and many other manufacturing applications. These phenomenon are inherently nonlinear and their realistic modeling is crucial to understanding their true dynamic behavior primarily applied to automotive squeak. The approach involves wavelets to quantify the frequency-time characteristics of the stick-slip and noise events. Modern dimensionality theory incorporating state space variables is used to accommodate the nonsmoothness of stick-slip systems. Direct measurements of friction during velocity reversals lead to establishing relationships between the friction and the displacements, velocities, accelerations, and time. Educational innovations include developing a nonlinear oscillation course for off-campus delivery, incorporating computers in courses, projecting animations in lectures, and performing physical demonstrations in the classroom to illustrate complex dynamic phenomena.
