The Implementation of the Gurson–Tvergaard–Needleman Model for Simulation of Cold Forging Processes of Incompressible Materials

Prediction of workpiece fracture during metal forming operations is necessary for designing technological processes of cold forging. The micromechanical Gurson–Tvergaard–Needleman model is widely used in general purpose software systems (LS-DYNA, ABAQUS) to calculate metal fracture. However, these systems are rarely used for simulation of forging technological operations for a number of reasons. The incompressibility condition contained in the resolving system of equations prevents the implementation of this model in specialized programs for simulating forging processes. This article proposes an approach that takes into account the change in metal deformation resistance depending on the predicted porosity derived from the Gurson–Tvergaard–Needleman model and allowing for the incompressibility of the material. The method is implemented as a subroutine for QForm Russian software, widely used for simulation of forging, rolling, drawing and pressing. Model validation is performed by comparing it with the results of the calculations in LS-DYNA.

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