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| Crystal Plasticity Object Oriented Finite-element (OOF) Modeling |
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The OOF (Object Oriented Finite-element)[1] project at the National Institute of Standards and Technology is a research and software project whose focus is on the finite-element modeling of materials with complex multicomponent spatial structure. While the OOF software itself is suitable for modeling materials at any length scale, the obvious domain of applicability is that of ``ordinary'' materials which exhibit multicomponent spatial complexity at micrometer length scales.
An important goal of the second version of the OOF software, currently being researched at NIST, is the greatest possible breadth of applicability. To this end, the new software incorporates a well-defined interface through which individual properties can be included in new material models. The generic nature of this interface is the mechanism through which the breadth of applicability is achieved. Consequently, the question of how to construct this API is an important research topic for the OOF project.
This topic can be addressed from the point of view of the most-often-requested constitutive feature for the new version of OOF, namely, plasticity. Consistent with other aspects of OOF development, we expect that the interface and constitutive relations will have to be sufficiently general to be applicable to a wide class of problems, and at the same time familiar to materials researchers. For many OOF-accessible problems, the materials will be well approximated by assemblies of crystalline grains, so the corresponding model of plastic response will be an anisotropic model which respects the slip systems and orientation of the host lattice, but stops short of modeling individual dislocations. This is the domain of crystal plasticity[2].
We are, therefore, researching and developing both the general programmatic interface for OOF properties, capable of handling crystal plasticity, and an extensible family of plastic constitutive laws for common lattice symmetries which uses this interface. |
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