FINITE-ELEMENT ANALYSIS OF A CRACKED ELLIPSOIDAL INHOMOGENEITY IN AN INFINITE BODY AND ITS LOAD-CARRYING CAPACITY

In particle or short-fiber reinforced composites, cracking of reinforc ements is a significant damage mode because the cracked reinforcements lose load carrying capacity. This paper deals with elastic stress dis tributions and load carrying capacity of intact and cracked ellipsoida l inhomogeneities. Axisymmetric finite element analysis has been carri ed out on intact and cracked ellipsoidal inhomogeneities in an infinit e body under uniaxial tension. For the intact inhomogeneity, as well k nown as Eshelby's solution (1957), the stress distribution is uniform in the inhomogeneity and nonuniform in the surrounding matrix. On the other hand, for the cracked inhomogeneity, the stress in the region ne ar the crack surface is considerably released and the stress distribut ion becomes more complex. The average stress in the inhomogeneity repr esents its load carrying capacity, and the difference between the aver age stresses of the intact and cracked inhomogeneities indicates the l oss of load carrying capacity due to cracking damage. The load carryin g capacity of the cracked inhomogeneity is expressed in terms of the a verage stress of the intact inhomogeneity and some coefficients. The c oefficients are given as functions of an aspect ratio for a variety of combinations of the elastic moduli of inhomogeneity and matrix. It is found that a cracked inhomogeneity with high aspect ratio maintains h igher load carrying capacity than one with low aspect ratio.