Mechanical Engineering – Engineering Mechanics Graduate Seminar: Thurs., April 18 at 4:00 in 112 MEEM. Professor Steven W. Shaw, Department of Mechanical Engineering, Michigan State University
Title: “Using Nonlinear Torsional Vibration Absorbers to Improve Automotive Fuel Economy”
Steve Shaw is a University Distinguished Professor in the Department of Mechanical Engineering at Michigan State University. He received an AB in Physics (1978) and an MSE in Applied Mechanics (1979) from the University of Michigan and a PhD in Theoretical and Applied Mechanics (1983) from Cornell University. His current research interests are in dynamical systems and mechanical vibrations, including mirco/nano-scale resonators with sensing and signal processing applications, and nonlinear vibration absorbers with automotive applications. He has held visiting appointments at Cornell University, the University of Michigan, Caltech, the University of Minnesota, the University of California-Santa Barbara, and McGill University. Steve currently serves as an Associate Editor for the SIAM Journal on Applied Dynamical Systems, Nonlinear Dynamics, and the ASME Journal of Vibration and Acoustics. His work has been supported without interruption by the US NSF since 1984, and by the US Department of Defense and industrial sources. He is a Fellow of ASME and recipient of several honors, including the SAE Arch T. Colwell Merit Award, the Henry Ford Customer Satisfaction Award, the ASME Henry Hess Award, and he will receive the ASME N. O. Myklestad Award in 2013.
Topic: Using Nonlinear Torsional Vibration Absorbers to Improve Automotive Fuel Economy
A number of approaches used for improving automotive fuel economy result in increased levels of powertrain torsional vibration; these include cylinder deactivation, low-speed boosting, and low-speed torque converter lockup. One can maximize the effectiveness of such strategies by managing torsional vibrations, which allows access to more efficient operating conditions.
Several manufacturers are considering the use of centrifugal pendulum vibration absorbers, which are widely used in light aircraft engines, for this purpose. These absorbers attenuate torsional vibrations at a given engine order, and they are most effective when lightly damped and allowed to operate at large amplitudes of oscillation. Hence, their design requires an understanding of the dynamic response of a multi-degree-of-freedom nonlinear system driven near resonance. Some nonlinear effects can be designed into the absorbers to provide enhanced performance, while others are detrimental to their function. In this work we consider the dynamics and performance of rotors fitted with multiple absorbers, a nonlinear dynamical system with special symmetries that are central to its behavior. We show how one can systematically account for these effects to develop analytical and computational tools for the design of absorber systems that are effective over a wide range of engine torques and speeds. The presentation will describe modeling, predictive analysis, controlled experiments,
automotive engine testing, and outstanding challenges related to these vibration absorbers.
This line of research has been carried out jointly with Professors Brian Feeny and Alan Haddow and several graduate students at MSU, Dr. Bruce Geist at Chrysler Group LLC, and Jeff Chottiner, John Brevick, and Victor Borowski at Ford Motor Company. Financial support has been provided by NSF, Chrysler, and Ford.