On contribution of pores into the effective elastic properties of carbon/carbon composites

In this paper, we discuss the effect of porosity on the effective elastic properties of unidirectional carbon/carbon composites (carbon fibers in pyrolytic carbon matrix) densified by chemical vapor infiltration (CVI). It is shown that CVI treatment results in formation of irregularly shaped pores randomly oriented in the plane perpendicular to the direction of fiber (transverse plane). These pores are analyzed using numerical conformal mapping procedure, 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 pores shapes.