Strain Localization Analysis by a Combination of the Espi With a Bulge Test

The problem of strain localization is important in sheet metal forming, as it determines the forming limit diagram of the material. To analyze this process, engineers use a variety of tests. One of them is the bulge test. In it, an initially flat specimen is placed between a matrix and a blank holder, and hydraulic pressure is applied on one of its surfaces. An approximately equi-biaxial strain loading path is obtained [1,2].