PhD, University of Cincinnati, 2005, Engineering : Mechanical Engineering

Microslip friction plays an important role in determining vibratory response to external excitation of frictional interfaces. Surfaces in contact undergo partial slip prior to gross slip. This mechanism provides significant energy dissipation as a result of interface friction, thereby considerably reducing vibratory response of the system. Developing physics-based phenomological models for frictional contacts is the underlying aim of our study. Both analytical and numerical approaches have been employed for characterizing the interface friction behavior. Numerical approaches have traditionally employed bilinear hysteresis elements to simulate frictional contact. Single degree of freedom (SDOF) models that only include a single hysteresis element have been the focus of research in the past. Though these models capture the interface behavior qualitatively, they cannot be truly representative or predictive of the underlying physics of frictional joints. A multiple degree of freedom (MDOF) model built from a finite number of hysteresis elements can discretize the continuous friction interface, and is inclusive of the microslip approach. However, parameter estimation constitutes an important aspect of these models, and currently it is carried out using a calibration approach rather than physical motivation. We have developed a class of multiple degree of freedom (MDOF) model that account for microslip behavior of friction joints. The models take into account the damper mass, which was studied by very few models in the past. This adds significant dynamics to the phenomological model, thereby providing a more efficient tool to simulate friction joints using numerical models. These models are successful in capturing hysteresis behavior of frictional contacts. They also depict the exponential scaling of frictional energy dissipation with applied forcing level. As such, the richness of the frictional interface can be captured using these models. A complimentary analytical sol (open full item for complete abstract)

Committee: Dr. Edward Berger (Advisor) Subjects: Engineering, Mechanical