# A finite element material model for microfracture-damaged brittle rock. [SANCHO code]

## Abstract

A continuum damage model based on the mechanics of microcrack growth has been implemented in the finite element code SANCHO. The model incorporates the effects of the nucleation, growth and coalescence of microcracks on the deformation of brittle materials, such as rock, under compressive loading. The material subroutine keeps track of both the magnitude and direction of microcrack growth in each element so that the induced anisotropy due to crack growth in preferred directions and the stress history dependence of microcrack growth are properly taken into account. In addition, the model allows for interaction among neighboring microcracks, which leads to coalescence and subsequent material failure or softening. A damage vector, which is calculated from the crack distribution in each element, is used as an internal variable to compute the effective elastic moduli at each stage of the deformation. Results of several sample calculations using the model are presented and methods for determining the required material parameters are discussed.

- Authors:

- Publication Date:

- Research Org.:
- Sandia National Labs., Albuquerque, NM (USA)

- OSTI Identifier:
- 6464045

- Report Number(s):
- SAND-87-1227

ON: DE87012511

- DOE Contract Number:
- AC04-76DP00789

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 58 GEOSCIENCES; ROCKS; DEFORMATION; S CODES; COMPRESSION; CRACKS; DAMAGE; FAILURES; FINITE ELEMENT METHOD; COMPUTER CODES; NUMERICAL SOLUTION; 580300* - Mineralogy, Petrology, & Rock Mechanics- (-1989)

### Citation Formats

```
Costin, L.S., and Stone, C.M.
```*A finite element material model for microfracture-damaged brittle rock. [SANCHO code]*. United States: N. p., 1987.
Web.

```
Costin, L.S., & Stone, C.M.
```*A finite element material model for microfracture-damaged brittle rock. [SANCHO code]*. United States.

```
Costin, L.S., and Stone, C.M. Mon .
"A finite element material model for microfracture-damaged brittle rock. [SANCHO code]". United States.
```

```
@article{osti_6464045,
```

title = {A finite element material model for microfracture-damaged brittle rock. [SANCHO code]},

author = {Costin, L.S. and Stone, C.M.},

abstractNote = {A continuum damage model based on the mechanics of microcrack growth has been implemented in the finite element code SANCHO. The model incorporates the effects of the nucleation, growth and coalescence of microcracks on the deformation of brittle materials, such as rock, under compressive loading. The material subroutine keeps track of both the magnitude and direction of microcrack growth in each element so that the induced anisotropy due to crack growth in preferred directions and the stress history dependence of microcrack growth are properly taken into account. In addition, the model allows for interaction among neighboring microcracks, which leads to coalescence and subsequent material failure or softening. A damage vector, which is calculated from the crack distribution in each element, is used as an internal variable to compute the effective elastic moduli at each stage of the deformation. Results of several sample calculations using the model are presented and methods for determining the required material parameters are discussed.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {1987},

month = {6}

}