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The sheet metal forming is conventionally studied using circular grid analysis. The recent developments in image processing techniques have made more accurate prediction of forming strains possible. Optical strain analysis is difficult for shop floor quality because of the higher cost of the system. Besides, the optical strain analyzer demands certain illumination requirements. Hence, conventional circular grid analysis is preferred for formability inspection at shop floor level. This paper focuses in benchmarking the circular grid analysis technique against the optical strain analysis for an automotive component. In the current work, the results of finite element analysis of a stamping process are initially validated with more accurate optical strain analysis. Later, the validation is done separately with circular grid analysis and the results of circular grid analysis are compared against that of optical strain analysis.

Automotive sheet metal components involve complex geometry and large surface areas. In addition to complex geometry, thrust for reduction of the new product development cycle demands for virtual simulation before prototyping. However in order to validate the simulation parameters, the numerical model needs to be experimentally verified. Conventional strain measurement techniques like Mylar tape, Traveling microscope are tedious and error prone for sheet metal forming analysis. Recently, optical strain measurement techniques are being used in sheet metal forming industry. Through this, strain measurement is more accurate, less time consuming and repeatable. This paper discusses a case study in which the analysis results of an automotive sheet metal component are experimentally validated by circular grid analysis using an optical strain measurement method. The circular grids are marked in the sheet metal blanks by screen-printing.