Title page for ETD etd-04062005-112716


Type of Document Master's Thesis
Author Taqieddin, Ziad N.
Author's Email Address ztaqie1@lsu.edu
URN etd-04062005-112716
Title Damage Mechanics of Composite Materials Using Fabric Tensors
Degree Master of Science in Civil Engineering (M.S.C.E.)
Department Civil & Environmental Engineering
Advisory Committee
Advisor Name Title
George Z. Voyiadjis Committee Chair
Peter I. Kattan Committee Member
Su-Seng Pang Committee Member
Suresh Moorthy Committee Member
Keywords
  • damage mechanics
  • composite materials
  • fabric tensors
Date of Defense 2005-03-31
Availability unrestricted
Abstract
The major objective of this work is to relate continuum damage mechanics introduced

through the concept of fabric tensors to composite materials within the framework of

classical elasticity theory. A model of directional data-damage mechanics for composite

materials is formulated using fabric tensors. In addition, a general hypothesis for damage

mechanics is postulated. It is seen that the two available hypotheses of elastic strain

equivalence and elastic energy equivalence may be obtained as special cases of the

postulated general hypothesis. This general hypothesis is then used to derive the sought

relationship between the damage tensor for composite materials and the fabric tensors.

Two approaches to link the fabric tensors damage effect to the behavior of composite

materials are adopted. The first approach is the continuum approach, which introduces

damage with fabric tensors to the composite media; where the latter is treated as a

homogenized material. Properties of the constituents are homogenized before the damage

with fabric tensors is introduced. The second approach is the micro-mechanical approach,

where damage with fabric tensors is introduced to the constituents rather than to the

homogenized material. Within the framework of classical elasticity theory, both

approaches should lead to equivalent results. Thus, a comparison between the two

approaches is carried out to verify their equivalency.

Damage evolution for both approaches is derived in a mathematically consistent

manner that is based on sound thermodynamic principles. Numerical examples and

application to the theory developed herein are presented. Micro-crack distributions in

different constituents of the composite material are thoroughly investigated.

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