Estimation of surface and interface strains in deformation processing using an ensemble averaged digital image correlation method

Gupta, D and Viswanathan, K (2024) Estimation of surface and interface strains in deformation processing using an ensemble averaged digital image correlation method. In: Journal of Manufacturing Processes, 120 . pp. 86-95.

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Abstract

The fundamental interaction between a tool and a workpiece is representative of many manufacturing processes, and commonly involves complex spatio-temporal deformation. While digital image correlation (DIC) has recently emerged as a promising method to estimate full-field strains, its application to deformations characterized by evolving free surfaces (e.g., chip in machining) or intensely sheared interfaces (e.g., frictional contacts in extrusion) has remained a central challenge. In this work, we address this challenge using a novel DIC method that exploits an ensemble of random grids. Termed ensemble averaged DIC, this scheme allows us to perform averaging of deformation fields across multiple grid realizations, eliminating the need for any post-processing. The use of second order derivatives in the computation ensures continuous strain and displacement fields. We first benchmark the scheme's performance against artificially generated deformation fields in order to quantify its accuracy and resolution. Following this, demonstrations of strain field determination in two prototypical manufacturing processes � orthogonal machining and extrusion-like sliding � are presented. The scheme is shown to accurately reproduce strain fields in the vicinity of evolving features such as the chip free surface, unsteady shear plane as well as on the final machined/ deformed surface. These regions represent problematic cases for conventional DIC analyzes and are consequently left out in the final fields. Our results show that the ensemble averaging scheme can help estimate difficult-to-measure process metrics such as residual surface strain in machining, and frictional strains in extrusion-type sliding. © 2024

Item Type:	Journal Article
Publication:	Journal of Manufacturing Processes
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd.
Keywords:	Benchmarking; Extrusion; Friction; Strain; Strain measurement, Chip formations; Digital image correlation methods; Digital image correlations; Ensemble-averaged; Frictional interface; Machining analyse; Manufacturing process; Strain analysis; Strain fields; Surface strains, Image correlation
Department/Centre:	Division of Mechanical Sciences > Department of Design & Manufacturing (formerly Centre for Product Design & Manufacturing)
Date Deposited:	17 May 2024 06:19
Last Modified:	17 May 2024 06:19
URI:	https://eprints.iisc.ac.in/id/eprint/84744

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