Ares J. Rosakis


Ares J. Rosakis Theodore von Kármán Professor of Aeronautics and Professor of Mechanical Engineering at the California Institute of Technology. He was also the fifth Director of the Graduate Aerospace Laboratories, known as, and formerly known as Guggenheim Aeronautical Laboratory, and was the Otis Booth Leadership Chair, .

Education/Career

Ares Rosakis graduated from Athens College, a Greek-American high school in June 1975. In September 1975, he moved to the United Kingdom to attend University College Oxford to study engineering science. Dr. Rosakis received his BA and MA degrees in Engineering Science from Oxford University in 1978. He went on to earn his ScM and PhD degrees in solid mechanics from Brown University. He joined Caltech and GALCIT as an assistant professor in 1982 as the Institute's youngest tenure tract 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. In 2013, he was honored as the inaugural recipient of the Otis Booth Leadership Chair, Division of Engineering and Applied Science.

Research Interests

Professor Rosakis is the author of more than 260 works on quasi-static and dynamic failure of metals, composites, interfaces and sandwich structures, with emphasis on the use of high speed visible and IR diagnostics and laser interferometry for the study of dynamic fracture and dynamic localization. His early work includes the study of dynamic, ductile failure of structural metals by using high speed photography, the real-time measurement of temperature fields at the vicinity of dynamically growing cracks and adiabatic shear bands and the development of a variety of optical and dynamic infrared diagnostic methods. He and his coworkers invented Coherent Gradient Sensing, CGS, interferometry, a method sensitive to gradients of optical path gradients which has been used in both fracture mechanics and thin film stress measurements at the wafer level. Other interests include dynamic fragmentation; shear dominated intersonic rupture of inhomogeneous materials and composites, rupture mechanics of crustal earthquakes, shielding of spacecraft from hypervelocity micrometeoroid impact threats, the reliability of thin films and wafer level optical metrology. Professor Rosakis holds thirteen US patents on thin-film stress measurement and in situ wafer level metrology as well as on high speed infrared thermography.
In the late eighties, Rosakis introduced the concept of "laboratory earthquakes" and since then his research interests have mainly focused on the mechanics of seismology, the physics of dynamic shear rupture and frictional sliding and on laboratory seismology. The goal of this body of work is to create, in a controlled and repeatable environment, surrogate laboratory earthquake scenarios mimicking various dynamic shear rupture process occurring in natural earthquake events. Such, highly instrumented, experiments are used to observe new physical phenomena and to also create benchmark comparisons with existing analysis and field observations. The experiments use high-speed photography, full-field photoelasticity, and laser velocimetry as diagnostics. The fault systems are simulated using two photoelastic plates held together in frictional contact. The far field tectonic loading is simulated by pre-compression while the triggering of dynamic rupture is achieved by suddenly dropping the normal stress in a small region along the interface. The frictional interface forms various angles with the compression axis to provide the shear driving force necessary for continued rupturing. Rosakis and his co-workers, investigate the characteristics of rupture, such as rupture speed, rupture mode, associated ground motion under various conditions such as tectonic load, interface complexity and roughness. Both homogeneous and bimaterial interfaces are investigated. Rosakis and his coworkers have been credited with the experimental discovery of the "intersonic" or "supershear rupture" phenomenon. They also have investigated this new phenomenon in various engineering and geophysical settings involving shear dominated rupture in the presence of weak interfaces or faults. Their experimental discoveries of supershear rupture has refocused the attention of the geophysics community to the study of supershear earthquakes.
Another recent research interest for Professor Rosakis is hypervelocity impact. Hypervelocity impact is a rising concern in spacecraft missions where man-made debris in low Earth orbit and meteoroids are capable of compromising or depleting the structural integrity of spacecraft. To address these concerns, the goal of current research is to experimentally investigate the underlying mechanisms responsible for deformation and damage evolution during hypervelocity impact utilizing Caltech/JPL's Small Particle Hypervelocity Impact Range facility. By combining high speed photography, optical, spectroscopic and infrared techniques, including Coherent Gradient Sensing interferometry, the dynamic perforation behavior involving crater morphology, debris and ejecta formation and solid/fluid/plasma transitions and interactions have been examined.

Academic Leadership

May 2009 – 2015, As EAS Division Chair
2004- 2009, As Director of GALCIT
Caltech Leadership and Service
Rosakis has been honored with many recognitions in mechanics, in aerospace and in materials failure including the 1989 Rudolf Kingslake Medal and Prize from the International Society of Optical Engineering and with various prizes awarded by the . These include the 1992 Hetényi Award, the 1996 B. L. Lazan Award, and the 2003 Frocht Award. In 2005 the same society selected him to become the William M. Murray Medalist and Lecturer for his lifelong contributions to the development and application of advanced methods for accurate measurement of transient, dynamic phenomena. In 2007 he received the Harting Award.
In 2009, he was elected a Fellow of the American Academy of Arts and Sciences. In 2010, he received the Award from the Brown University School of Engineering, and the Robert Henry Thurston Award from the American Society of Mechanical Engineers. In 2011, he received the A. Cemal Eringen Medal from the Society of Engineering Science and he was elected Fellow of the National Academy of Engineering. In 2012, he was appointed Commandeur dans l'Ordre des Palmes Académiques from the Republic of France. In 2013, he received the P.S. Theocaris Award from the Society of Experimental Mechanics for his lifelong contribution to experimental science and mechanics, he was elected member of the European Academy of Sciences and Arts, and he was elected Foreign Fellow of the Indian National Academy of Engineering and a corresponding member of the Academy of Athens. In 2014 he was elected member of Academia Europaea. In 2015 he received the Sia Nemat-Nasser Medal from SEM for his interdisciplinary utilization of experimental mechanics to advance the field of earthquake Seismology. And most recently in 2016, he was elected to the National Academy of Sciences and awarded the Theodore von Karman Medal of the American Society of Civil Engineers.
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Professor Rosakis is the author of over .