The School of Mechanical and Materials Engineering Seminar Series, “Mechanistic Insights into Ultra-Low Wear Dry Sliding of Tribological Polymer Composites” Presented by Dr. Harman Khare

About the event

Mechanistic Insights into Ultra-Low Wear Dry Sliding of Tribological Polymer Composites

Presented by Dr. Harman Khar, Assistant Professor, Mechanical Engineering, Gonzaga University

Abstract:

Polymers and polymer composites are versatile solid lubricants which help reduce friction, regulate wear, and improve reliability of contacting surfaces in relative motion. These tribological interfaces are ubiquitous in mechanical and biological systems, ranging from ball bearings in a bicycle, to seals in a gas turbine engine, to the contact between cartilage and bone in our knees. Frictional dissipation at these interfaces contributes to wasted energy and increased greenhouse emissions; wear of materials on the other hand can result in seizure and catastrophic failure of entire systems, or onset of debilitating diseases such as arthritis. Polymer composites which exhibit the lowest wear rates invariably exhibit the formation of tribofilms and transfer films, i.e. mechanochemically modified material layers on the sliding surface of the composite and on the sliding counterface. Although interfacial films are necessary for a polymer composite to exhibit sustained low wear, factors and mechanisms within the composite and at the interface which drive their formation are poorly understood. Using empirical observations from one low-wear system often translate poorly when attempting to predict reliability of another system. A lack of fundamental understanding of the pair-wise interactions between fillers, matrix and counterface therefore preclude predictive design of low-wear polymer matrix composites. This talk will outline several research projects in the Gonzaga Tribology Research Lab aimed at understanding mechanochemical interactions of polymer composites at dry sliding interfaces.

Presenter Biography:

Harman Khare is an Assistant Professor of Mechanical Engineering at Gonzaga University, where he also leads the Gonzaga Tribology Research Laboratory. Prior to joining the Gonzaga Engineering faculty, he was a Postdoctoral Researcher and later Manager of Research Projects at the University of Pennsylvania. He completed his doctoral training at the University of Delaware, which incidentally was where he first heard the word ‘tribology’. His research interests are broadly in the area of multiscale experimental tribology, including solid lubricants, polymer tribology, scanning probe microscopy and custom design of scientific instrumentation.  When not in lab measuring the slipperiness of surfaces, he enjoys running, hiking, tennis and woodworking.