Micromechanical modeling of porous carbon/carbon composites

A procedure to model fiber-reinforced composites containing pores of irregular shapes is presented. Closed-form expressions for contributions of fibers and pores into effective elastic moduli are provided. The procedure is applied to predict the transverse elastic properties of unidirectional carbon/carbon composites (carbon fibers in pyrolytic carbon matrix) densified by chemical vapor infiltration. Infiltration treatment results in the formation of irregularly shaped pores randomly oriented in the plane perpendicular to the direction of fiber (transverse plane). These pores are analyzed using a numerical conformal mapping technique, and their contribution to the effective elastic properties is expressed in terms of the cavity compliance contribution tensor. Components of this tensor are found for a variety of typical pore shapes.