LOAD-CARRYING CAPACITY OF A BROKEN ELLIPSOIDAL INHOMOGENEITY

In particle or short-fiber reinforced composites, cracking of the rein forcements is a significant damage mode because the broken reinforceme nts lose load carrying capacity. This paper deals with elastic stress distribution and load carrying capacity of intact and broken ellipsoid al inhomogeneities. Axisymmetric and three dimensional finite element analyses have been carried out on intact and broken ellipsoidal inhomo geneities in an infinite body under uniaxial tension and under pure sh ear. For the intact inhomogeneity, as well known as Eshelby's solution [18], the stress distribution is uniform in the inhomogeneity and non uniform in the surrounding matrix. On the other hand, for the broken i nhomogeneity, the stress in the region near the crack surface is consi derably released and the stress distribution becomes more complex. The average stress in the inhomogeneity represents its load carrying capa city, and the difference between the average stresses of the intact an d broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The load carrying capacity of the broken inhom ogeneity is expressed in terms of the average stress of the intact inh omogeneity and some coefficients. The coefficients are given as functi ons of an aspect ratio for a variety of combinations of the elastic mo duli of inhomogeneity and matrix. It is found that a broken inhomogene ity with high aspect ratio maintains higher load carrying capacity tha n one with low aspect ratio. (C) 1997 Acta Metallurgica Inc.