ARES J. ROSAKIS Theodore von Kármán Professor of Aeronautics and Mechanical Engineering California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 Tel: 626-395-4523; Email: [email protected]; Website: http://rosakis.caltech.edu
Brief Biosketch
Education: Ares Rosakis was born in Athens Greece in September 12, 1956. He graduated from Athens College, a Greek-American high school, in June of 1975. In September of 1975, he moved to the United Kingdom to attend University College Oxford and to read engineering science. He received both his Bachelor’s (B.A.) and Master’s of Arts (M.A.) degrees from Oxford University. He went on to obtain his ScM. (1980) and PhD (1982) degrees in Engineering (solid mechanics and structures) from Brown University.
Positions Held: Rosakis joined the California Institute of Technology (Caltech) as an Assistant Professor in 1982 and as the Institute’s youngest tenure-track faculty member. He was promoted to the ranks of associate and full-professor in 1988 and 1993 respectively. In 2004, he was named the “Theodore von Kármán Professor” of Aeronautics and Professor of Mechanical Engineering. He holds this chair to this date.
Visiting Chairs: Vis. Professor, École Normale Supérieure, Paris (2005). Astor Vis. Professor, Oxford University, U.K. (2007).
University Leadership: Between 2009 and 2015, he served as the Chair, (“Dean” in other Institutions) of the Division of Engineering and Applied Science (EAS) at Caltech. In June 2013, Rosakis was also named the F. Otis Booth Leadership Chair in addition to his academic, Theodore von Kármán, Chair. This Leadership Chair, with its endowment, has been established in recognition of his many administrative achievements. Prior to this he served as the fifth Director of the historic Graduate Aerospace Laboratories (GALCIT) formerly, known as the Guggenheim Aeronautical Laboratories.
Awards, Medals and State Distinctions: NSF Presidential Young Investigator Award, presented by US President Reagan (1985). IBM Faculty Development award (1985).R. Kingslake Medal and Prize, SPIE (1989). Hetenyi (1992 & 2008), Lazan (1996), Frocht (2003), Murray (2005), Harting (2007) and Theocaris (2013) Awards from the Soc. for Experimental Mech. (SEM). Fellow, Amer. Soc. of Mechanical Engrs. (ASME) (1995). Excellence in Teaching Award, Caltech (1998). Fellow, SEM (2009). Distinguished Alumnus Medal, Brown University (2010). R.H. Thurston Award, ASME (2010). A.C. Eringen Medal, Soc. of Engrg. Science (2011). Commandeur dans l'Ordre des Palmes académiques, from the Republic of France (2012). Sia-Nemat-Nasser Medal, SEM (2015), Theodore von Kármán Medal (2016), American Society of Civil Engineers (ASCE)
Membership in National and International Academies: Fellow, New York Academy of Sciences (NYAS), (1999) Fellow, American Academy of Arts and Sciences (AAAS), 2009 Member, US National Academy of Engineering (NAE), 2011 Member, European Academy of Sciences and Arts (Academia Scientiarum et Artium Europaea), 2013 Foreign Fellow, Indian National Academy of Engineering (INAE), 2013 Corresponding Member, Academy of Athens (National Academy of Greece), 2013 Member, Academia Europaea (AE), 2014 Member, US National Academy of Sciences (NAS), 2016
Mentorship Rosakis has graduated 25 PhD students and mentored 16 postdoctoral fellows. 14 of his former PhD students (11 of them tenured) and 11 of his former postdoctoral fellows (6 of them tenured) now hold tenure-track faculty positions in 25 universities around the world.
Brief Summary of research accomplishments:
Ares Rosakis’ work has always been highly interdisciplinary in nature and has focused on applying the principles of fundamental solid mechanics and static and dynamic fracture to various disciplines within engineering and related sciences such as materials science and earthquake seismology. As such his work has resulted in both scientific discoveries and practical developments that have helped invigorate the field of fracture and failure mechanics and have highlighted its importance in modern engineering practice.
The scientific part of his work has been instrumental in introducing new theoretical and experimental approaches to solving problems and discovering new phenomena in disciplines such as Materials Science, space engineering and Earthquake Seismology. The engineering part of his work has resulted in the insertion of novel concepts and optical diagnostic instruments of relevance to the microelectronics industry. His research interests span a multiplicity of length and time scales ranging from sub-μm (thin films) to 105m (earthquake fault rupture) and from nano seconds (hypervelocity impact in space) to years (creep fracture and tectonic processes). He has also been a leader in education through his innovative teaching and mentorship of students and through the creation of new educational programs at Caltech as well as formal international education and research exchanges with France and India.
For over 35 years, Rosakis and his collaborators have contributed to a wide spectrum of areas within engineering science, including the experimental, theoretical and numerical study of materials reliability, fracture mechanics and dynamic localization phenomena. His earlier work concentrated on the study of dynamic fracture of metals and resulted in the first comprehensive formulation of dynamic crack initiation, crack growth and crack arrest criteria in solids of relevance to engineering practice (metals, metallic glasses, ceramics, polymers and composites). From the purely experimental instrumental point of view, Rosakis has invented a number of optical diagnostic techniques both in the visible and infra-red wavelength range and has successfully combined them with ultra-high speed photography (100 million frames/s) and high-speed infrared thermography (1 million frames/s) to study previously unexplored dynamic fracture and adiabatic strain localization problems. In parallel to his experimental efforts, he has developed an array of analytical and computational models for analyzing dynamic fracture and localization phenomena, which have resulted in fundamental advances towards understanding dynamic failure processes in solids.
In the mid-1980s, he and hos co-workers, invented a new full-field optical technique, the Coherent Gradient Sensor method, or CGS. CGS is a shearing, laser interferometer sensitive to gradients of surface topography, when used in a reflection mode, and gradients of refractive index, when used in a transmission mode. Rosakis applied this method to the study of dynamic interfacial fracture of bonded solids with applications to composite materials and sandwich structures. Rosakis made singular contributions to this field, including the scientific discovery of shear dominated transonic debonding in various layered systems of Engineering significance (Debonding fracture fronts propagating at speeds above the lowest of the shear wave speeds of the composite and the highest of the pressure wave speeds of the layered system). He has also applied CGS and high speed photography to the study of impact and fragmentation of ceramics and brittle polymers as well as to the investigation of hypervelocity impact phenomena applied to the study of micrometeorite impact on space structures and the protection of space assets from space debris.
One of the most notable applications of CGS is the application of this method to the study of the reliability of thin-film structures and thin-film problems. This has included in-situ wafer metrology and real-time optical monitoring of large, 300mm, production wafers during processing. This invention has resulted in a venture capital-funded Caltech spin-off company, “Oraxion Diagnostics”, and has generated considerable enthusiasm in micro-electronics and opto-electronics industry. The resulting instrument has been used as a tool for yield management by major industry players such as Intel, Semetech and Applied Materials in addition to various fabrication facilities in Taiwan and Singapore. In 2006, the technology of this startup was absorbed by Ultratech, a leader in semiconductor processing and metrology. In addition to developing CGS interferometry for wafer inspection and measurement during various processing steps, Rosakis and collaborators have also developed theoretical micromechanics models to be used in the analysis of the CGS interferograms. The combined use of such models with the CGS measurements allow for the accurate inference of thin-film stresses in the micron and sub-micron scale, in the presence of film thickness non-uniformities in multiple layers and three dimensional patterning. In the same time period, Rosakis and his students were also instrumental in developing the fastest existing high speed, full-field, microprobe infrared thermal camera (1 million frames/second), which was applied to the real-time study of dynamically growing shear bands with implications for high speed machining and penetration mechanics. Both these inventions have been granted a total of 13 U.S. patents.
In the 1990s, Rosakis’ work on the dynamic fracture of heterogeneous and layered solids attracted considerable international attention from both the geophysics and the earthquake seismology communities. Of particular interest to these communities was a section of his work related to the dynamic rupture of frictionally held interfaces separating similar and dissimilar materials. In this body of work, he collaborated with seismologists and geophysicist’s to design novel experiments, which mimic earthquake rupture in various controlled laboratory settings.
Through these experiments, which reproduce the basic physics of earthquake rupture, he was able to discover that earthquake ruptures may propagate with super-shear speeds (Speeds in excess of the bulk shear wave speed of the surrounding material). He also conclusively proved (in collaboration with Geo-Mechanicians and Seismologist) that certain historic, large earthquakes indeed transitioned to Super-shear, and explained the unusual ground–shaking signatures, which are characteristic of such events.
In the past fifteen years, his pioneering experiments and laboratory discoveries, have also helped resolve a number of additional cutting-edge problems and paradoxes in earthquake source physics and mechanics, including the directionality of rupture growth in heterogeneous faults, the mechanism of creation of off-fault damage, the selection between “pulse-like” or “crack-like” modes in earthquake slip and the possibility of “fault opening” at the earth’s surface during certain thrust fault earthquakes.
These discoveries proved to be of particular interest to the geophysical community and resulted in symposia at professional meetings in both engineering and geophysical societies such as the American Society of Mechanical Engineers (ASME), the American Geophysical Union (AGU), the Seismological Society of America (SSA), the American Physical Society (APS) and in special volumes of journals. These were devoted to discussing and interpreting Rosakis’ experimental discoveries in relation to field observations of such super-shear earthquake events and sequences hosted by the San Andreas, Denali, Alaska, North Anatolian and the Tibetan faults.