What, if Anything, Can Chemistry Offer to Fracture Mechanics?

Abstract

Chemistry is primarily concerned with the structures and properties of bonds between atoms and with relating these bonds and their properties to the structure, reactivity, and other properties of molecules. The principle concerns of chemistry have thus been individual molecules and molecular reactivity. Attention is now slowly turning to the structure, reactivity, and properties of solids: that is, to collections of molecules and to very large molecules. Why slowly? Certainly not because the problems in the solid state, or more broadly in materials science, are unimportant. The objectives of rationalizing properties such as tensile modulus, fracture strength, corrosion resistance, electrical conductivity using atomic-level structural information, dielectric constant, and thermal conductivity are clearly simultaneously immensely interesting scientifically and important technologically.^1,2 They are also, unfortunately, very difficult to attain. Moreover, the difficulty often is of an annoying sort--that is, it is associated with defects. The properties of large, regular ensembles of atoms and bonds can often be calculated with a high degree of precision using standard techniques of statistical mechanics.³ What cannot be readily calculated is the often critical influence of unknown impurities or defects of unknown composition and structure on the properties of interest.