Interaction Stresses in Composite Systems

The nature of stress distribution generated by the presence of inclusions and voids in an otherwise homogeneous matrix has been studied. A model has been developed idealizing the random nature of inclusions and voids in two-phase and three-phase composite materials. A finite element numerical method was adopted for the analysis of the previously unsolved problem of multiple inclusions and voids. Stress fields and stress concentration factors are determined as a function of elastic moduli, spacings, and Poisson's ratio. Stress distribution due to inclusions or voids and the interaction effect due to the presence of other inclusions or holes in the immediate vicinity are studied in detail. The interaction effects are more predominant with closer spacing. Comparison of results by the numerical method with experimental results shows good correlation. High stresses are found to be localized at the interface of inclusions, regardless of modular ratio and Poisson's ratio of inclusion.