Presently, I collaborate with the OOF team at the National Institute of Standards and Technology (NIST) within the Materials Science Division, specifically in the Thermodynamics and Kinetics group. The focus of our work involves the implementation of a 3D Crystal Plasticity framework into OOF. OOF is a specialized Finite Element software tailored for simulating microstructural-based problems. Its primary functionality lies in calculating macroscopic properties derived from images of actual or simulated microstructures. OOF processes images, attributes material properties to features within the image, and conducts virtual experiments to deduce the macroscopic properties of the microstructure. Subsequently, the Finite Element tool within OOF is employed to simulate the microstructure under various mechanical loadings.
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The implementation of the Crystal Plasticity Code is designed to cater to three distinct material types:
Single Crystal Level for Two-Phase Materials (e.g., Nickel-based Superalloys):
At this level, an explicit representation of two-phase materials is simulated. A dedicated code has been developed in both Python and C++ environments, written from scratch. This code incorporates non-linear finite element methods within the crystal plasticity framework.
Single Crystal Level for Homogenized Materials (FCC, BCC, and HCP Lattice Structures):
This level involves the development of different constitutive equations, ranging from simple power law to dislocation density-based models, for homogenized materials with FCC, BCC, and HCP lattice structures. A separate code, also developed in Python and C++, employs non-linear finite element methods within the crystal plasticity framework.
Polycrystalline Level for Polycrystal Microstructures:
At this level, constitutive models are formulated, taking into account grain orientations and grain boundaries. The existing code for this level is in the form of UMAT and is developed in the Fortran environment.