Woodruff School of Mechanical Engineering
Faculty Candidate Seminar
Deformation Mechanics and Process Innovation in Incremental Forming for Sustainable Manufacturing
Mr. Rajiv Molhatra
Friday, February 24, 2012 at 11:00:00 AM
MRDC Building, Room 4211
Dr. Shreyes Melkote
Manufacturing has tremendous potential for making transitive contributions to sustainability by reducing energy consumption, enhancing material usage and improving process flexibility. The development of new forming processes that meet these challenges is one way to achieve these goals. This talk focuses on one such process, Incremental Forming (IF). In IF one or two small hemispherical ended tools move along a predefined toolpath to locally deform a peripherally constrained sheet metal blank. The cumulative effect of these local deformations imparts the sheet its final shape. Improved energy efficiency, low cost and generic tooling, greater process flexibility and increased formability are characteristics of IF that make it a very attractive addition to sustainable manufacturing. This talk will focus on work done towards understanding fracture and improving geometric accuracy in IF. The occurrence of fracture in IF is predicted using a damaged base material model in FEA and the predictions are shown to match well with experimental observations. The deformation trends predicted by FEA are analyzed to pinpoint the primary deformation mechanisms that affect fracture in IF. A new “noodle” theory is proposed that explains the increased formability which is commonly observed in IF. Additionally this theory also establishes a link between IF process parameters and formability. Furthermore, significant enhancement of the process capabilities of IF via fundamental process modifications and intelligent toolpath design will also be presented. Finally, it will be shown that this work lays the foundation for the creation of new sustainable and hybrid forming processes and stimulates the creation of rapid process optimization techniques, which can then be combined to fully exploit the capabilities of flexible manufacturing.
Mr. Malhotra joined the Department of Mechanical Engineering at Northwestern University for his PhD in 2008. During his tenure at NU he has received the Predictive Science and Engineering Design (PSED) Cluster fellowship, the Murphy Graduate Fellowship and has been a visiting scholar to the Indo-US Center for Research Excellence. As an outcome of his research he has published five journal papers as first author and filed two patent applications. Additionally he has presented at national and international conferences and received a best presentation award as well as a best paper award at SME/NAMRC 2011. Since 2008 he has worked on two NSF sponsored projects and a DOE sponsored project on Incremental Forming. He has made significant computational and experimental advances in Incremental Forming towards understanding and improving formability, enhancing geometric accuracy, creating automated toolpath design methodologies and developing a new Double Sided Incremental Forming machine. During this time he has also collaborated on Incremental Forming research with the Ford Motor Company, MIT, Penn State University and Prof. Ted Belytschko at NU.
Refreshments will be served.