Characterization of Interphase/Interface Parameters of Unidirectional Fibrous Composites by Optimization-Based Inverse Homogenization

Abstract

Optimization-based micromechanical and inverse-homogenization models are developed to inversely calculate the interphase/interface properties of unidirectional periodic fibrous composites from prescribed effective properties or localized stress concentrations. The interphase/interface effects between fibers and the surrounding matrix are described by four different mathematical models that are reviewed in the present work. In order to guarantee the stability of the characterization process, two sophisticated micromechanical models, locally exact homogenization theory and finite-volume direct averaging micromechanics, are introduced in this work and connected to the gradient-free particle swarm optimization to search for the optimal parameters to minimize the cost/objective functions that consider the homogenized or localized responses of unidirectional composites. The accuracy and efficiency of the proposed procedure are tested by substituting the optimized parameters back into the direct micromechanical models and validating against the target functions, where good agreement is always obtained. More importantly, the numerical effects generated by those parameters are also tested on the effective properties and localized stress distributions of fibrous composites.