Numerical simulation of saturation behavior of physical properties in composites with randomly distributed second-phase

Second-phase materials are generally added to a matrix material in order to improve its physical properties. To enhance the thermal conductivity and stiffness of a polymer material, some powders and/or short-fibers are used. Physical properties such as thermal conductivity and elastic modulus of the composites with randomly distributed second-phase are computed by the use of the finite element methods and verified by experimentation. The computation results show that there exists a saturated property ratio of the second-phase to the matrix at a certain volume fraction. The saturated ratio increases with the increase of volume fraction and the fiber length to diameter ratio. Beyond this saturated ratio, the physical properties of the composite cannot be further improved by enhancing the corresponding property of the second-phase material. A comparison with other analytical models indicates that some models may predict the saturation behavior well while some others may not.