Elasto-Plastic Stress Analysis Methodology Establishment for Forging Dies

Finite Element Analysis (FEA) is an important engineering tool used to assist in approximating and verifying how a component will react under various complex loading conditions. There are many conditions where the stress applied could extend beyond the yield point of the material but FEA does not necessarily provide visual indication that the part has yielded. Elastic material property has a linear stress-strain relationship regardless of the load applied while the elastic-plastic has a linear relationship up to yield point and then becomes nonlinear beyond yield point.In this study tensile tests and finite element analysis were carried out on forging die material. The unidirectional monotonic tensile tests were carried out on MTS machine. The Hypermesh and ANSYS FEA tools are used for elastic and elastic-plastic FEA. The mechanical behavior and stresses at critical locations under realistic forging process loading condition is investigated based on elastic and elastic-plastic FEA. Specifically, the elastic-plastic response under forging loading conditions beyond the elastic limit is studied. The stress - strain of die material was determined and used as input of a nonlinear finite element study aimed at investigating the stress evolution in the forging die. The forging die elastic FEA was carried out based on basic material properties, while elastic-plastic FEA was carried out based on material nonlinearity Von misses isotropic hardening plasticity criteria. The study concludes that elastic- plastic FEA gives more accurate die stress value and critical locations.