Forming Limit Diagram Generation from In-Plane Uniaxial and Notch Tensile Test with Local Strain Measurement through Digital Image Correlation

Requirement of forming limit curve appears indispensible for property check during formable sheet metal development cycle and quality control of formable sheet metal at production shop floor. In the present work, left side of the forming limit curve (uniaxial tensile to plane strain tensile) is experimentally determined from in-plane uniaxial and notch tensile test with local strain measurement through digital image correlation technique. A novel procedure has been developed to generate forming limit curve with considerably reduced experimental effort. The proposed new procedure is based on a combination of in-plane uniaxial notch tensile test with local strain measurement and modeling. The forming limit curve generated using the new procedure has been compared with the standard procedure (Nakajima test) and a good correlation has been obtained.