The Ohio State University

ABSTRACT:
An electromagnetic (EM) launcher is a structure containing two conductive rails that guide a projectile or armature up to velocities of several thousand meters per second via an electromagnetic force. This technology has been under development by DARPA and the Department of Defense for over two decades given it has advantages as a weapon system with respect to lethality, time of flight, accuracy, and logistics. Yet, while the application of EM launch is attractive, progress has been hampered by armature drag and rail longevity. Optimal performance is anticipated if armature-to-rail contact is maintained throughout sliding; however, intermittent contact is experienced from vibration of the armature and rails and melting at the armature-to-rail interface.
     This presentation will summarize experimental results and finite-element analyses (FEA) of the armature-to-rail contact of a lab-scale electromagnetic launcher housed in the Laboratory for Extreme Tribology at Georgia Tech. Aspects of the tribological interface including armature/rail melting, contact pressure, contact area, and wear will be presented with vibration characteristics (frequencies, amplitudes, mode shapes) through a parametric evaluation varying materials, their properties and geometric inputs. 
     Using the commercial code ANSYS, an electromagnetic finite-element analysis has been performed to determine the forces that result from an applied electric current and electromagnetic field. Meaningful conclusions shall be offered and supported through experimental and diagnostic evidence.

BIO:
Dr. Cowan (Ph.D. 2002, MSME 1992, Georgia Tech) is a Senior Research Engineer and Engineering Manager in the Manufacturing Research Center at the Georgia Institute of Technology, Atlanta, GA where he has performed and steered high profile research related to reducing the impact and incidence of mechanical system, component and material failure. His efforts include the development of a tribological laboratory in support of a $5M DoD MURI grant dedicated to the study of contacting surfaces under extreme electromagnetic stress. His professional interests include the strategic management of technology, equipment asset management and surface engineering, including thermal phenomena, wear, and fatigue. He has authored over a dozen peer reviewed journal papers and book chapters concerning diagnostic monitoring and maintenance. He is a licensed Professional Engineer in New York State and has held engineering and management positions at TRW Bearings Division (now MRC Bearings of SKF Aerospace) and Cummins Engine Company. Dr. Cowan was named a Congressional Fellow by the American Society of Mechanical Engineers (ASME) in 1998. He served as Executive Chair of the ASME Tribology Division (2003-05), and Secretary of its Predictive Maintenance Technical Committee. He is a recipient of the Saturn Company Award for Teamwork.

Hosted by Professor Bharat Bhushan, 292-0651, bhushan.2@osu.edu in Scott Lab, Room E001
For information on ME 888 seminars contact Professor Walter Lempert at 292-2736 or lempert.1@osu.edu.