14. Formability and Simulative Tests in Modern Sheet Metal Forming Education

This chapter provides the theoretical and experimental background to the utilization of circle grid analysis in conjunction with formability and simulative laboratory tests at undergraduate and graduate courses of metal forming with the objective of exposing students to machine-tools, tool systems and practical problems that are commonly found in daily production of sheet metal parts. The presentation starts with a description of strain measures and measurements techniques, extends this background to plastic instability and fracture, introduces the forming limit diagrams and systematizes the associated formability tests, and reviews the process simulation tests aimed at characterizing bendability, stretchability and drawability of blanks. Then, presentation proceed with a comprehensive description of a flexible, versatile and robust laboratory tool system that was developed by the authors to support education and basic research activities of sheet metal forming. The last part of the chapter presents the fundamentals of a simple finite element computer program developed by the authors that gives support to sheet metal forming laboratory tests and provides students with a strong link between experimentation and numerical simulation.