Micromechanics-Based Interfacial Debonding Model for Damage of
Functionally Graded Materials with Particle Interactions

G.H. Paulino¹, H.M. Yin¹, and L.Z. Sun²*

¹Department of Civil and Environmental Engineering, Newmark Laboratory,

University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

²Department of Civil and Environmental Engineering and Center for Computer-Aided Design, The University of Iowa, Iowa City, IA 52242, USA

ABSTRACT: A micromechanical damage model is developed for two-phase functionally graded materials considering the interfacial debonding of particles and pair-wise interactions between particles. Given an applied mechanical loading on the upper and lower boundaries of a functionally graded material, in the particle-matrix zones, the interactions from all other particles over the representative volume element are integrated to calculate the homogenized elastic fields. A transition function is constructed to solve the elastic field in the transition zone. The progressive damage process is dependent on the applied loading and is represented by the debonding angles which are obtained from the relation between the particle stress and the interfacial strength. In terms of the elastic equivalency, the debonded, isotropic particles are replaced by the perfectly bonded, orthotropic particles. The effective elasticity distribution in the gradation direction is correspondingly solved. Numerical simulations are implemented to illustrate the capability of the proposed model.

KEY WORDS: functionally graded materials (FGMs), micromechanical modeling, damage mechanics, interfacial debonding, pair-wise particle interaction.