TY - JOUR

T1 - Anisotropic damage mechanics based on effective elliptical microcracks

AU - Lesieutre, George A.

AU - Fang, Lei

AU - Lee, Usik

N1 - Funding Information:
Acknowledgements-This work was supported by the Office of Naval Research under the "Integrated Predictive Diagnostics" MURI at Penn State University. Dr David Hall is the Principal Investigator, while Prof. Joseph Cusumano leads the "Failure Dynamics" sub-thrust. Their encouragement and advice is gratefully acknowledged.

PY - 1997

Y1 - 1997

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.

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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

T2 - Proceedings of the 1997 38th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Part 4 (of 4)

Y2 - 7 April 1997 through 10 April 1997

ER -