THE ROLE OF MATRIX CRACKING IN THE CONTINUUM CONSTITUTIVE BEHAVIOR OF A DAMAGED COMPOSITE PLY

Abstract

Modeling of damage growth in composite materials has proceeded primarily at the micro-mechanics level. Although adding considerably to our understanding of the phenomena, it is difficult to directly include these models in predictions of performance and ultimate failure of composite material structures because of the enormous complexity involved. Thus, a continuum theory of damaged ply constitutive behavior has been introduced (Nuismer, 1978) as a vehicle for including micro-damage effects in a tractable way. As originally formulated, this continuum theory was basically phenomenological in nature, although predicated on simple physical models of damage in composite plies. In the present paper, the first in a series of steps is taken to directly include more realistic physical models of micro-damage into the continuum theory. Specifically, a new micro-mechanics model is introduced to describe the initiation and growth of matrix cracking in a ply subjected to transverse tension. The implications of this development to the continuum theory of damaged ply constitutive behavior are discussed and the need for future work is outlined.