Multi-scale Finite Element Cellular Automata Simulation of Multi-step Cold Forging Operations

摘要

The application of new materials to produce forged connecting parts is presented in this work. Particular attention is put on modern bainitic steels due to their increased ductile and strength properties, which influence the behaviour of final products under further exploitation conditions. Bainitic steels do not require a series of thermo-mechanical operations to obtain these elevated properties, which is one of the advantages of this material. Experimental analysis and numerical simulations of steel behaviour during multi-step cold forging operations are described in this paper. Since it is one of the possible fracture initiation mechanisms, strain localization development during cold forging is investigated in detail. Conventional constitutive models used in finite element programs have limitations in modeling stochastic and discontinuous phenomena that are responsible for strain localization. The cellular automata model is used as constitutive law in this work to overcome these difficulties and investigate material flow during multi-stage cold forging operations. Connection of the cellular automata (CA) and finite element (FE) methods creates a so-called multi-scale CAFE model. The main aspects of the model are described briefly in this paper. The experimental part of this work supports the numerical investigation. Comparison of the parameters measured and predicted by the CAFE model is presented and discussed as well.