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Finite Element and Finite Difference Programs for Computing the Linear Electric and Elastic Properties of Digital Images of Random Materials.


pdf icon Finite Element and Finite Difference Programs for Computing the Linear Electric and Elastic Properties of Digital Images of Random Materials. (14033 K)
Garboczi, E. J.

NISTIR 6269; 211 p. December 1998.

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB99-132888

Keywords:

building technology; computer models; concretes; electrical conductivity; eigenstrain; elastic moduli; finite difference; finite elements; linear properties; microstructure; random materials; thermal elasticity; transport properties

Abstract:

This manual has been prepared to show some of the theory behind, and the practical details for using, various finite element and finite difference computer programs that have been developed for computing the effective linear properties of random materials whose microstructure has been stored in a 2-D or 3-D digital image. Thirteen different computer programs are described, including finite element conductivit,y a,nd elastic programs, finite difference programs for D.C. and AC. conductivity, finite element elastic programs that include thermal strains (eigenstrains), and three auxiliary programs for Gaussian quadrature and phase percolation. All the programs are writ,ten in FORTR,AN 77, and operate on an arbitrary digital image that is read from a file. Arbitrary symmetric conductjivity tensors and arbitrary elastic moduli tensors can be used in the finite element programs. In the finite difference programs, the conductivity tensors must be diagonal. Only linear elastic and linear electrical conductivity problems are considered. The programs can of course be extended to other problems that have a similar mathematical basis.