Difference between 2D and 3D capturing and influence of strain rate on FLC diagram of DC.01 steel

Purpose: The aim of this work is to develop a method for evaluating forming limit curves measured at high strain rates using drop tower while specimens are being captured by high-speed camera (2D). Design/methodology/approach: This article describes the first step to establishing such method – verification of compatibility between 3D and 2D capturing by ARAMIS system. Findings: Within this work, FLD recorded in 3D and 2D mode were determined. After correction of the angle α between projection onto the normal plane to direction of loading and tangent in the point where crack occurred, the obtained FLD diagram were almost identical. Research limitations/implications: Optical methods, such as digital image correlation used by ARAMIS measuring system, offer very detailed information of material’s surface at high resolution while significantly reducing the preparation and evaluation time for specimens testing. Originality/value: The analysis of true plane major strains in the forming limit diagram (FLD) is still the most established method for failure detection of sheet metal forming processes in industrial praxis. With the prerequisite of linear strain paths it is very simple to predict the start of necking by using the FLD.