Department of
Mechanical and Nuclear Engineering
Committed to Teaching, Research, and Service
Search: This Site | People | Departments | Penn State
Research & Facilities - Research - Tribology
Faculty
Dr. Liming Chang, Dr. Aman Haque
Research Areas
Design and analysis of machine contact and lubrication systems; tribology in micro-electromechanical systems.
Research Projects
Design Theory for Centrally-Pivoted Thrust Bearings
Oil lubricated slider bearings are widely used to support thrust loading in various rotating machinery. The majority of such bearings in industrial applications employ centrally-pivoted plane pads for reasons of easy manufacturing and reversal operations. However, the classical theory of hydrodynamic lubrication documented in lubrication and machine-design books predicts zero load capacity of such bearings, and the guidance provided in handbooks on bearing designs lacks a sound theoretical basis. Thus, a fundamental defect exists in the design theories of such bearing systems, which could prevent design innovations beyond the current experience-based engineering practices. The project aims to fix this theoretical defect by developing a comprehensive basis upon which design selections and calculations can be meaningfully carried out for this class of thrust bearings.
Oil Life Monitoring for IC Engines
In recent years, the cost of drain intervals of engine oils to the economy, to the environment and to vehicle owners has received more attention and the development of a meaningful oil life monitoring system is desirable. A meaningful life algorithm should factor in major chemical, thermal and mechanical effects such as cold weather effects (condensation and acids formation), high-temperature oxidation and thermal breakdown, mechanical stresses and wear, short-duration frequent-cranking operations, operating environmental conditions, oil aging and engine aging. This projects aims to develop a comprehensive formulation of a general oil-life monitoring system for IC engines and develop a life-monitoring algorithm implementable into engine system to notify operator the time to change the oil.
Modeling of Boundary Lubrication
Boundary lubrication of metallic surfaces is a complex and interdisciplinary process. Generally, it involves engineering mechanics, heat transfer, surface physico-chemical science and random-process probability. Sensible and balanced considerations of all the four aspects, both theoretically and experimentally, may further our understanding and engineering practices of this lubrication process. This projects aims to develop a theoretical platform for modeling the boundary lubrication of nominally flat metallic contacts. The platform is envisioned to be of a general structure with four interrelated modules, each governing one of the four key processes of the problem. It is also envisioned to be open-ended allowing individual modules to be updated and/or replaced. The product and the outcome may provide an infrastructure for fundamental research in boundary lubrication among theoreticians and experimentalists and across several science/engineering disciplines.