Seminars

Dead material zones—stationary regions of adhered material at the tool–workpiece interface—are a recurring feature in large-strain deformation processes such as metal cutting and indentation. Despite their practical significance, the mechanisms governing their initiation and evolution remain poorly understood, largely due to the difficulty of resolving local deformation events in real time. In this study, we present direct in situ evidence of dead zone formation using a high-resolution experimental framework based on ensemble-averaged digital image correlation (EADIC) and synchronized force measurements. Across three distinct metallic systems—Al6061-T6, Ti6Al4V, and Inconel 718—we identify a consistent two-stage mechanism:
(i) adhesion-induced pinning of material at the tool tip and (ii) internal shear leading to the delineation of a nascent dead zone, followed by gradual material accumulation and resulting in geometric stabilization. These stages are shown to influence chip morphology, cutting forces, and surface defect formation. We also establish a clear correspondence between the surface features and the underlying deformation events associated with each stage. Overall, the findings offer mechanistic insight into chip–tool interactions and lay the groundwork for controlling dead zone behavior while explaining the origin of the observed surface features.

Bio: Deepika Gupta is a Postdoctoral Researcher in Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin. Her research focuses on the mechanics of fracture, interfaces, and large-deformation processes in heterogeneous material systems, with an emphasis on resolving the local processes governing deformation, contact, and interfacial separation through in-situ experimental measurements. She received her Ph.D. in Mechanical Engineering from the Indian Institute of Science, where she developed in-situ experimental frameworks and the Ensemble Averaged Digital Image Correlation (EADIC) method to quantify large-strain deformation in metal cutting. Her work received the Best Doctoral Symposium Award at the American Society of Mechanical Engineers Manufacturing Science and Engineering Conference in 2022. Prior to joining UT Austin, she worked as a Research Engineer at Saint-Gobain Research India. At UT Austin, her research investigates interfacial fracture in layered material systems relevant to electronic packaging, combining high-resolution deformation measurements with mechanics-based analysis to quantify traction–separation relations governing interface failure.