OOF: Finite Element Analysis of Microstructures

OOF: Finite Element Analysis of Microstructures is installed on all HPC workstations.

Type oof2 to start this program

Documentation can be found at http://www.ctcms.nist.gov/~langer/oof2man/index.html.

OOF2 is public domain software created at the National Institute of Standards and Technology (NIST) to investigate the properties of microstructures. The microstructure of a material is the (usually) complex ensemble of polycrystalline grains, second phases, cracks, pores, and other features occurring on length scales large compared to atomic sizes.

At the simplest level, OOF2 is designed to answer questions like, “I know what this material looks like and what it's made of, but I wonder what would happen if I pull on it in different ways?”, or “I have a picture of this stuff and I know that different parts expand more than others as the temperature increases -- I wonder where the stresses are greatest?”

One approach for investigating microstructural behavior is to reduce the representation of a microstructure to a small number of physical parameters (such as grain size or porosity) and develop a model which depends on them. If this type of reductionist approach is predictive, then such models can be extremely useful. However, when physical properties depend on microstructural details (such as the spatial correlation of crystallite orientation, the shapes and dispersion of second phases, extremes of statistical distributions, or local anisotropies) such data reduction is often difficult or pointless.

OOF2 takes a non-reductionist, brute force approach, but in a user-friendly way. The user starts with a digitized image of the microstructure and builds a data structure on top of it. All the data plus any that can be inferred by the user is used. Tools are provided to allow the user to graphically select features in the microstructural image and specify their properties. For OOF2, the microstructure is a data structure composed of image and property data.

The idea of basing calculations on images is not new. Edward Garboczi and colleagues at NIST have used this approach to investigate behavior of cements and porous media. Researchers at Alcoa have developed finite element models of textured materials. The purpose of creating OOF2 and distributing it freely is to supply a generic tool for calculating microstructure-property relations.