Some New Rheological Phenomena and their Significance for the Constitution of Materials

Abstract

THE materials studied in rheology are of varied constitution, with intricate patterns of constituent components of visible, colloidal, molecular, atomic and sub-atomic sizes. The patterns range from a coarse-grained type in which a discontinuous structure is apparent, to a fine-grained one which appears homogeneous and continuous to the eye and even to the microscope ; the former type is represented by biological tissues, textile materials, natural and synthetic sponges, foams, powders, timber, cement, etc., and the latter by gases, amorphous liquids and solids, single crystals, etc. In the engineering constructions of Nature and man, widespread use is made of coarse- and fine-grained materials, and this invites an investigation into their mechanical properties as exhibited in changes of volume and form, and into the relation between these properties and the constitution of the materials.