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Ares J. Rosakis B.Sc., University of Oxford, 1978; Sc.M., Brown University, 1980, Ph.D., 1982 1200 East California Boulevard | website
Research The research in Professor Rosakis's group is part of the program in mechanics at Caltech and is concerned with the experimental, numerical, and analytical investigation of dynamic deformation and failure in modern monolithic materials and composite structures. On the experimental side, efforts concentrate on the development of novel optical diagnostic techniques to be used in conjunction with ultra-high-speed photography (up to 50 million frames/sec) for the study of transient deformation and failure events in real time. Optical techniques such as the Coherent Gradient Sensor (CGS), which was developed by our group in 1988, are used for the characterization of dynamic fracture phenomena in metal alloys (ceramics, geomaterials, metallic glasses, bimaterial interfaces, and composites). Recent interests include the study of shear dominated ruptures along weak paths, bonds, or geographical faults. This has followed our experimental discovery of intersonic shear crack growth phenomena associated with shear-induced dynamic failure of interfaces between similar or dissimilar materials. In addition to its obvious relevance to the study of fracture response in composite structures, this work is also relevant to the study of geological earthquake ruptures. On the related subject of dynamic constitutive response and localization in solids, high-speed temperature measurements are used to provide a complete thermomechanical characterization of materials subjected to a variety of loading rates and loading histories. A unique two-dimensional IR high-speed camera has been developed, in collaboration with Professor G. Ravichandran, for the real-time visualization of transient temperature fields associated with dynamic cracks and adiabatic shear bands. Finally, other interests include the use of CGS interferometry for the study of the reliability of structures of interest to the microelectronic industry (thin films, interconnects, membrane structures, and MEMS).
Selected Publications Observations of Transient High Temperature Vortical Microstructures in Solids During Adiabatic Shear Banding (with P. R. Guduru and G. Ravichandran), submitted to Physical Review Letters, 2000 Experimental Observations of Intersonic Crack Growth in Asymmetrically Loaded Unidirectional Composites Plates (with D. Coker), to appear in Philosophical Magazine A, 2000 Cracks Faster than Shear Wave Speed (with O. Samudrala and D. Coker), Science, 284, pp. 1337-1340, 1999 Intersonic Crack Propagation in Bimaterial Systems (with O. Samudrala, R. P. Singh, and A. Shukla), Journal of the Mechanics of Physics of Solids, Special Volume on Dynamic Deformation and Failure Mechanics of Materials, G. Ravichandran, A. J. Rosakis, M. Ortiz, Y. D. S. Rajapakse, and K. Iyer, eds., 46, pp. 1789-1813, 1998 Temperature Rise at the Tip of Dynamically Propagating 31 May, 2007Detectors (with A. T. Zehnder), Experimental Techniques in Fracture, J. Epstein, ed., Chapter 5, pp. 125-169, 1993 Two Optical Techniques Sensitive to Gradients of Optical Path Difference: The Method of Caustics and the Coherent Gradient Sensor (CGS), Experimental Techniques in Fracture, J. Epstein, ed., Chapter 10, pp. 327-425, 1993 |
