Accurate Damage Evolution and Lifetime Prediction Drs. Thomas Mackin and Nancy Sottos, of the University of Illinois are applying infrared imaging and micromechanics to provide detailed analysis of damage evolution and its relation to composite microstructure. Dr. Sottos has investigated the micro-mechanics of interface damage such as that typically found in the layered material of an aircraft s wing skin. The infrared imaging method provides a precise quantitative measure of the current stress state, the evolution of damage during loading, and the resulting stress redistribution. Recent application of the IR method on polymer composites enabled a quantitative measure of impact damage and provided a new method for accurately predicting the remaining fatigue lifetimes of the damaged composites.
Results indicate that the very complex process of damage initiation and growth can be predicted.
The model traces damage evolution in textile composites subjected to thermal and mechanical loads and evaluates the relative influence of different fiber architectures such as woven, knitted, and braided patterns. Use of this new model will allow material designers to develop strategies for avoiding premature failures. A Georgia Institute of Technology professor s work has potential for important advances in the ability to detect missiles during their boost phase. Dr. Raymond Flannery s microscopic theory of three-body recombination processes of electrons and ions in gases has improved researchers understanding of collisions between atoms and molecules in specific highly excited states. By improving the understanding of rocket exhaust radar signatures, for example, the Air Force will be better able to detect missiles during boost phase.