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

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.
*