Graduate Seminar Series
Please check Seminar Announcements for time and location.
Monday November 16, 2009 | 320 Randolph Hall at 4pm: A comprehensive testing of different shock absorbers for three passenger cars and heavy trucks were carried out to study their performance on vehicle ride and stability. For this purpose, a quarter vehicle model, half vehicle model and full vehicle model simulating vehicle suspension testing were developed to study the effect of actual characteristics of the shock absorbers on vehicle performance. The shock absorber characteristics were represented by the linear average value of shock absorber (both rebound and compression strokes), bi-linear (the linear rebound, and the compression strokes with different slopes) and actual measurements characteristics. For ride comfort, the results showed that the actual shock absorber characteristics have strongly affected the ride comfort. It improved the ride quality comfort by 58% compared to the model that employed linear characteristics for the shock absorber. Also using the gas charged single tube shock absorber in soft mode improved the ride performance by 58% compared to the hard mode at different speeds. On the other hand, for rough roads, using the gas charged single tube shock absorber in the hard mode was shown to improve the ride performance by 27% and the stability in terms of the pitch angle by 33% compared to the soft mode for the same road profile. Hosted by: Dr. Corina Sandu |
Thursday, November 19, 2009 | 1060 Torgersen at 9am: Automotive Engineering at Technische Universität Darmstadt (FZD) is a chair and a research institution within the Department of Mechanical Engineering and is directed by Prof. Dr. H. Winner. The scientific employees do research with the support of student assistants primarily in the following six subject areas: Advanced Driver Assistance Systems; Vehicle Dynamics; Motorcycles; Brake Systems; Safety and Test Procedures. The predo¬minant part of the FZD research is carried out in projects lasting several years supported by the automobile and sup¬plier industry, e.g. Audi, BMW, Bosch, Continental, and Daimler. Currently FZD is working on projects like "Optimization of Driving Dynamics by Coordinating ESP and Damping Control", "Advanced Driver Assistance System for Overtaking Maneuvers" and "Vehicular Communication for Motorcycles" or "Intelligent Lightweight Brake Disc." Hosted by: Dr. Corina Sandu |
Friday November 20, 2009 | 320 Randolp Hall at 4pm: Cell migration is an important physiological process that has been extensively studied by biologists for decades. However, the focus has always been on identifying the genes and proteins that regulate the process. Increasingly, there is growing appreciation that the mechanical and physical aspects of how cells migrate are important too. This is an area where mechanical engineers and physicists can contribute extensively. In this presentation, three examples of applying physical principles to various aspects of cell migration will be discussed. First, we study the mechanics of the lamellipodia, which are actin-rich sheet-like protrusions that cells develop to adhere to and exert traction on their substrates in order to migrate. We develop a mathematical model of the lamellipodia protrusions, and use this model to predict how the velocity of protrusion depends on the rigidity of the substrate. Second, we study the mechanics of blebs, which are blister-like protrusions of cell membranes driven by changes in intracellular pressure. We develop a quantitative model to study how a bleb develops when a portion of the cell membrane detaches from the underlying cortex. From the model, we calculate the minimum cytoplasmic pressure and minimum unsupported membrane length for a bleb to nucleate and grow. Third, we consider how cells move collectively as an epithelial sheet in a directed fashion. Using a model borrowed from statistical physics, we propose that differential adhesion regulates the coordinated migration of cells in the epithelium. Hosted by: Dr. Mark Paul |
Monday December 7, 2009 | 320 Randolph Hall at 4pm: Coal gasification and combustion can introduce contaminants in the vapor as well as solid or molten state depending on the gas clean up procedures used, coal composition and operating conditions. These byproducts when combined with high temperatures and high gas stream velocities can cause Deposition, Erosion, and Corrosion (DEC) of turbine components. The extent of damage done by DEC in the gas path is directly dependent on the impaction of solid or molten particulates on surfaces, which lead to erosion and deposition. One surface, which is particularly vulnerable, is the leading edge of vanes and blades in the presence of film cooling. The primary objective of the proposed research is to provide design data to engineers by studying fluid-particle dynamics in the leading edge region of a turbine blade in the presence of film-cooling jets and to quantify the potential deposition and erosion under different flow, thermal, and particle dynamics. There is no previous study in the gas turbine literature which has studied the hydrodynamic and thermal conditions under which DEC occurs at the leading edge in the presence of 3-hole film cooling geometry. The work uses the method of time-accurate Large-Eddy Simulations (LES) as a theoretical tool for simulating carrier phase and a Lagrangian framework for tracking the particle dynamics. The talk will focus on the dynamics of flyash deposition on a three-row film cooled leading edge vane geometry. Advisor: Dr. Danesh Tafti |