The next generation metal continuum plasticity theory

The shape change of a metal is mathematically described by theories of metal plasticity. This is a special case of material plasticity and can be described by the available continuum plasticity theories. In a microscope, one sees that a metal consists of small crystals (grains). A more detailed description and understanding of metal plasticity can be obtained by studying the contributions from each crystal, i.e. from theories of crystal plasticity. With today's computers, large-scale simulations of the metal's behavior are not possible from these detailed models. Nevertheless, our understanding of crystal plasticity and our experimental realization from mechanical testing indicate that an improved continuum description of metal plasticity is necessary. This requires appropriate mathematical modifications of the continuum models. The goal of the METPLAST project is to develop the next generation of continuum plasticity models for metals. In the first part of the project, the focus has been on establishing stable and robust software to be able to perform virtual experiments in computer-simulated experiments that are calculated crystal plastically. In the second phase, the continuum models will be tested and developed.

Important basic ingredients of the continuum plasticity theory are ripe for revision. Basic mechanisms that today only can be predicted by the more detailed but computationally demanding crystal-plasticity models, will be incorporated into the continuum plasticity theory. The next generation continuum plasticity theory for metals will be developed, by developing and implementing new models required to reproduce virtual experiments by crystal-plasticity models. This will significantly improve the predictions of plastic buckling, anelasticity, flow instabilities during forming of plates and transient responses to strain-path changes.