Heterogeneous Material Mechanics at Various Scales

Some contemporary problems involving the mechanics of materials will be examined at widely different length scales. The three scales chosen are i) the near atomic scale, ii) an intermediate range of the order of microns, and iii) large scale macro or structural behavior. An additional theme transcending these scales will be carbon based, or carbon like heterogeneous material behavior. At the near atomic scale, examples are chosen from the various forms that elemental carbon can take including diamond, graphite, newly discovered fullerenes, and ideal carbon fibers. Examples at the intermediate length scale feature low density materials, since typical cell sizes are about a micron or somewhat larger or smaller. The effect of microstructure becomes the dominant and determining characteristic of such materials. A hierarchy of microstructures will be revealed which gives a coherent connection between microstructure and mechanical behavior. Finally, at the macroscale, involving structural behavior, a methodology for the life prediction of fiber dominated, graphite epoxy composites will be given. These three classes of problems are intended to show that virtually equal opportunities for meaningful research contribution occur across the spectrum of length scales.