THE EFFECT OF SLIGHTLY WEAKENED INTERFACES ON THE OVERALL ELASTIC PROPERTIES OF COMPOSITE-MATERIALS

The effect of imperfect interfaces on the overall elastic properties of composites is studied in this paper. The imperfect interface is modeled by a linear spring-layer of vanishing thickness. The Mori-Tanaka estimate and its modification are used to evaluate the effective moduli of composites having slightly weakened interfaces. An interface is said to be slightly weakened, if the compliance of the spring-layer is very small. As an example, a composite consisting of aligned ellipsoidal particles is considered in detail. Explicit expressions of the Mori-Tanaka estimates of the effective moduli are derived when the particles are spherical. Based on classical minimum energy principles, upper and lower bounds of the effective moduli of composites with imperfect interfaces are also derived.