### Abstract

A theory of damage mechanics is introduced based on a principle of strain energy equivalence. This principle is used to develop the effective continuum elastic properties of a damaged solid in terms of the undamaged elastic properties and a scalar damage field. The damage variable is defined as the volume fraction of a damage zone associated with equivalent elliptical microcracks. This definition provides a means by which a damaged isotropic material can exhibit anisotropic (orthotropic) properties, and entails determining effective crack orientation and geometry factors from the local deformation. Strain energy dissipation associated with crack growth (not nucleation) is used to develop a consistent damage evolution equation. This evolution equation is related to the standard power law model of crack growth commonly used in fracture mechanics, and to the equivalent stress measure commonly used in mechanics of plastic deformation. The combination of representing local damage as an effective elliptical crack volume fraction, a consistent damage evolution equation, and the determination of effective elastic properties using a strain energy equivalence principle yields a simple, yet powerful approach to predicting failure of mechanical components.

Original language | English (US) |
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Pages (from-to) | 2819-2832 |

Number of pages | 14 |

Journal | Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference |

Volume | 4 |

State | Published - Jan 1 1997 |

Event | Proceedings of the 1997 38th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Part 4 (of 4) - Kissimmee, FL, USA Duration: Apr 7 1997 → Apr 10 1997 |

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### All Science Journal Classification (ASJC) codes

- Architecture
- Materials Science(all)
- Aerospace Engineering
- Mechanics of Materials
- Mechanical Engineering

### Cite this

}

*Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference*, vol. 4, pp. 2819-2832.

**Anisotropic damage mechanics based on effective elliptical microcracks.** / Lesieutre, George A.; Fang, Lei; Lee, Usik.

Research output: Contribution to journal › Conference article

TY - JOUR

T1 - Anisotropic damage mechanics based on effective elliptical microcracks

AU - Lesieutre, George A.

AU - Fang, Lei

AU - Lee, Usik

PY - 1997/1/1

Y1 - 1997/1/1

N2 - A theory of damage mechanics is introduced based on a principle of strain energy equivalence. This principle is used to develop the effective continuum elastic properties of a damaged solid in terms of the undamaged elastic properties and a scalar damage field. The damage variable is defined as the volume fraction of a damage zone associated with equivalent elliptical microcracks. This definition provides a means by which a damaged isotropic material can exhibit anisotropic (orthotropic) properties, and entails determining effective crack orientation and geometry factors from the local deformation. Strain energy dissipation associated with crack growth (not nucleation) is used to develop a consistent damage evolution equation. This evolution equation is related to the standard power law model of crack growth commonly used in fracture mechanics, and to the equivalent stress measure commonly used in mechanics of plastic deformation. The combination of representing local damage as an effective elliptical crack volume fraction, a consistent damage evolution equation, and the determination of effective elastic properties using a strain energy equivalence principle yields a simple, yet powerful approach to predicting failure of mechanical components.

AB - A theory of damage mechanics is introduced based on a principle of strain energy equivalence. This principle is used to develop the effective continuum elastic properties of a damaged solid in terms of the undamaged elastic properties and a scalar damage field. The damage variable is defined as the volume fraction of a damage zone associated with equivalent elliptical microcracks. This definition provides a means by which a damaged isotropic material can exhibit anisotropic (orthotropic) properties, and entails determining effective crack orientation and geometry factors from the local deformation. Strain energy dissipation associated with crack growth (not nucleation) is used to develop a consistent damage evolution equation. This evolution equation is related to the standard power law model of crack growth commonly used in fracture mechanics, and to the equivalent stress measure commonly used in mechanics of plastic deformation. The combination of representing local damage as an effective elliptical crack volume fraction, a consistent damage evolution equation, and the determination of effective elastic properties using a strain energy equivalence principle yields a simple, yet powerful approach to predicting failure of mechanical components.

UR - http://www.scopus.com/inward/record.url?scp=0030679799&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030679799&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:0030679799

VL - 4

SP - 2819

EP - 2832

JO - Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

JF - Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

SN - 0273-4508

ER -