Extending Griffiths Theory to Cohesive Types of Dried Materials

摘要

The paper is concerned with condensed dispergate systems, as for example, solid suspensions, ceramic pastes used for production of electronic elements, clay for brick production, etc. These systems, after drying and calcination become porous with relatively high mechanical strength. The characteristic feature of the dispergate systems is their great amount of developed interfacial surfaces. It means that they contain a great amount of the surface energy. As a consequence of this, the particles (crystalline grains) tend to join each other and create agglomerates. By growth of the agglomerates the surface energy decreases but the particle bonds become thermodynamically stable. Two items are discussed in this paper: first, the maximal value of stress that can be carried by the body in a given stage of drying; and second, the criterium of fracture. Some knowledge concerning fracture of ceramics, like materials, is presented in monographs by Cottrell ([1]), Pampuch ([8]). General knowledge concerning drying problems is given, for example, in Kowalski ([5]), Kowalski and Strumillo ([6]).