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Influence of particle size and debonding damage on an elastic-plastic singular field around a crack-tip in particulate-reinforced composites

Keiichiro Tohgo (Shizuoka University)

Prager Medal Symposium in honor of George Weng: Micromechanics, Composites and Multifunctional Materials

Mon 2:40 - 4:00

MacMillan 117

This paper deals with the influence of particle size and debonding damage on an elastic-plastic singular field around a crack-tip in particulate-reinforced composites. Finite element analysis has been carried out on a crack tip field in particulate-reinforced composites with debonding damage and containing various sized particles. The finite element method was developed based on a micromechanics model of particulate-reinforced composites which can describe the debonding damage of particles from matrix and particle size effect on deformation and damage. The micromechanics model based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept was extended to consider the particle size effect, debonding damage of particles and plasticity of the matrix. The particle size effect on deformation was realized by introducing dislocation plasticity for stress-strain relation of in situ matrix in composites using the Nan-Clarke's simple method, and the particle size effect on damage was described by a critical energy criterion for particle-matrix interfacial debonding. The influence of particle size and debonding damage on an elastic-plastic singular field around a crack-tip is discussed based on the numerical results. The stress distribution ahead of a crack tip field shifts upward with decreasing particle size in the composites unless the debonding damage develops. In the composites with damage, the debonding damage occurs from a crack tip and progresses ahead of a crack tip. The stress distribution shifts downward in the progressive damage zone. It is concluded that the crack-tip field is strongly affected by the particle size and debonding damage.