Influence of the determination of FLC’s and FLSC’s and their application for deep drawing process with additional force transmission

This contribution deals with the experimental and numerical analysis of the material fracture behavior of steel sheet material HCT 600 X + Z (1.0941) in thickness s = 1.0 mm using the Nakajima test. Firstly, the Nakajima test is carried out, whereby the major and minor strains are measured with the optical measuring system ARAMIS. Here, two different estimation methods for determination of the strains are applied and sensitivity of estimated results related to different strain gauge lengths was analyzed. Hereby, the forming limit curve (FLC) is determined experimentally. Subsequently, the FEA of a Nakajima test was carried out and compared with corresponding experimental results. The flow behavior of HCT 600 is modelled using a planar anisotropic material model based on the Hill’s 1948 criterion, which was validated in previous work. Using FLC the simulation-based determination of the forming limit stress curve (FLSC) is carried out. Furthermore, two deep drawing processes, conventional and process with activation of additional force transmission are carried out producing the rectangle cups. Here, the larger process window is achieved. Within the numerical investigation of the material fracture behavior the FLC and FLSC are applied by FEA of both deep drawing processes. Finally, the assessment of the performed material modelling is presented.