Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
An anisotropic damage model for rock
Bibliography: pages 146-155.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Civil Engineering
2016
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613246793449472 |
|---|---|
| access_status_str | Open Access |
| author | Sellers, E J |
| author2 | Scheele, Friedrich |
| author_browse | Scheele, Friedrich Sellers, E J |
| author_facet | Scheele, Friedrich Sellers, E J |
| author_sort | Sellers, E J |
| collection | Thesis |
| description | Bibliography: pages 146-155. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/21488 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:05.164Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Civil Engineering |
| publisherStr | Department of Civil Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/21488 An anisotropic damage model for rock Sellers, E J Scheele, Friedrich Civil Engineering Bibliography: pages 146-155. An anisotropic damage model is proposed for the constitutive description of microcracking processes in brittle rock under a general loading path. Experimental data and micromechanical models are reviewed to quantify the effect of microcracking on the material stiffness and the mechanisms of microcrack formation in brittle rocks under compression are discussed. The sliding crack concept is adopted as the micromechanical basis of the anisotropic damage model. Undamaged material is represented with a linear elastic constitutive equation. Damage initiation is defined by a Coulomb friction law, which excludes damage at low deviatoric stress levels. The formulation of the directional damage extends the arguments of continuum damage models for tension cracking to general, tension and compression, stress states. This is achieved by the definition of damage in a subdomain of the total strain and the characterisation of the directional microcracking by a fourth order tensor internal variable, the damaged secant stiffness of the 'crack' strain subdomain. Induced anisotropy results from the reduction of components of the initial stiffness tensor in the direction of the positive principal 'crack' strains. Evolution of the damage magnitude is determined by the principle of maximum damage dissipation in terms of the undamaged energy norm of the positive part of the 'crack' strain tensor. Versatile evolution functions, based on the Weibull probability density function, are proposed for compression and extension damage modes. Unloading and reloading criteria are developed which are consistent with the sliding crack concept and introduce hysteretic behaviour. A numerical solution scheme is presented and the model is implemented in a nonlinear finite element program. 2016-08-24T12:51:25Z 2016-08-24T12:51:25Z 1994 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/21488 eng application/pdf Department of Civil Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Civil Engineering Sellers, E J An anisotropic damage model for rock |
| thesis_degree_str | Doctoral |
| title | An anisotropic damage model for rock |
| title_full | An anisotropic damage model for rock |
| title_fullStr | An anisotropic damage model for rock |
| title_full_unstemmed | An anisotropic damage model for rock |
| title_short | An anisotropic damage model for rock |
| title_sort | anisotropic damage model for rock |
| topic | Civil Engineering |
| url | http://hdl.handle.net/11427/21488 |
| work_keys_str_mv | AT sellersej ananisotropicdamagemodelforrock AT sellersej anisotropicdamagemodelforrock |