Breakage patterns of agglomerates

The experimental information available in the literature regarding the patt erns of breakage of agglomerate materials is scarce, particularly in dynami c loading. The primary objective of this paper is to present our findings o n the break-age patterns of the agglomerates and the interparticle bond. A high-speed digital video imaging technique is used here to gain an insight into the impact behaviour of individual agglomerates against a target plate . Several breakage patterns are observed. Agglomerates may suffer localised damage only, with the disintegration of the damaged zone into very fine de bris, or localised damage combined with fracture. The frequency of occurren ce of these patterns depends on the impact velocity and agglomerate structu re, The pattern of break-age affects significantly the size distribution of the impact product. An investigation of the breakage of individual interpa rticle bonds is also presented. Two forms of failure are observed, internal (cohesive) and interfacial (adhesive) failure. The morphology of the fract ured surface depends greatly on the type of breakage. Internal breakage sho ws irregular surfaces due to crack jumping, whereas interfacial failure pro duces clean, smooth fracture surfaces. These observations should provide th e necessary foundation for the development of a fundamental model of agglom erate breakage. (C) 2001 Elsevier Science B.V. All rights reserved.