EMPA, the Swiss Federal Research Laboratory for Materials Science and Technology, awarded the Golden Mirko Roš Medal to CEE Professor Oral Buyukozturk on May 16, during opening session of the 2011 International Symposium on Nondestructive Testing of Materials and Structures held at Istanbul Technical University. The award honors Buyukozturk’s “most valuable and sustained contributions to materials science and engineering in the domain of civil engineering, and for his outstanding research support to EMPA over the last two decades,” said Professor Urs Meier, a former director of EMPA.

“I have always had the opportunity and privilege to work in collaborative projects with EMPA’s researchers and sent them students,” said Buyukozturk. Summing up four decades of work, he said, “The basic philosophy of my research has been understanding the fundamental responses of materials and structures to loads and environmental effects such as moisture, temperature variations and chemicals, which we can predict using some powerful computational methodologies. No matter what the application area, the core research topic remains and consistently produces results and advancement in scientific knowledge and technology.”

In addition, Buyukozturk expresses great satisfaction “from developing something innovative and seeing it being used by people, and in educating young people. Teaching, research supervision and interaction with students are perhaps what I enjoy most,” he said.

After graduating from Istanbul Technical University, Buyukozturk received his Ph.D. in 1970 from Cornell University. As a graduate student at Cornell he did original and innovative work on the basic behavior of brittle materials such as concrete and mortar, and studied how micro-cracks develop. “As a group of people with a unique research approach, we coined the terminology of micro-cracking in brittle materials such as concrete as a composite. From micro-behavior we scaled up to predict the global behavior of the material, and then went even further to structures and systems,” he said.

This work also involved one of the first applications of the then-newly developing finite element method to analyze brittle materials and structures through nonlinear constitutive relations including debonding of interfaces between dissimilar materials. “It opened a new era in the study of the deformation response of brittle materials as a particulate composite and its formulations for engineering analysis,” said Buyukozturk.

Early work on computational engineering and infrastructure of energy facilities

Buyukozturk started his career working for the advanced power department of a major nuclear power plant construction company, investigating the integrity of pre-stressed concrete nuclear containment structures. He then moved to do research with a group at Brown University. He was involved in the development of unique finite element general-purpose programs as a basis for computational engineering, and pioneered models and methodologies that have been recognized worldwide and still used today. “Finite element analysis is a computational tool that revolutionized the entire engineering profession. I developed computer-based capabilities and nonlinear analysis programs for predicting material and structural behavior. All engineering fields use finite element analysis now as a major tool for analysis and prediction problems.”

After moving to MIT in 1976, Buyukozturk continued to apply computational capabilities to develop and design major energy facilities, starting with the safety evaluation of nuclear energy structures. With the energy crisis later that decade, the emphasis shifted toward offshore oil production structures. “The basic thrust of the research remained the same, but the application areas shifted according to critical national needs,” he said. His group worked on different energy system configurations, hydrodynamic forces on offshore structures and concrete gravity platforms in the North Sea using the similar basic concepts of material prediction, system prediction and computational methods.

His energy work also extended to the analysis and design of coal gasification vessels under high temperature where the ceramic materials and structural components are subject to thermo-mechanical and chemical deterioration in the process environment. Buyukozturk’s group undertook a leading role on this long-term, sustained project with an international consortium of about 15 companies.

When attention switched to the safety and durability of the nation’s infrastructure, Buyukozturk started using the fundamental modeling concepts to study bridges, dams and other structures. His group developed high-performance materials and high-performance concrete, with innovative applications to segmental concrete bridge construction and tall concrete buildings.

More recently, Buyukozturk’s research involves development and characterization of composite materials and their innovative use in designing high-performance structures. His group does pioneering work in modeling complex material behavior in multi-material systems involving interface fracture between different materials, durability in the face of moisture diffusion and temperature effects, and assessment of overall durability and life cycles of material and structural systems. “We made major contributions to the deterioration science of composite materials in terms of the durability of multi-material systems when they’re used for strengthening purpose, and what happens when fiber reinforced polymer material sheets are epoxied to another material subjected to water diffusion,” he said.

Novel methods for assessing and repairing deteriorating infrastructure

A native of earthquake-prone Istanbul, Buyukozturk takes a special interest in retrofitting and repairing structures there with innovative materials. “Fiber-reinforced polymer composites are lightweight, but stiff and strong or stronger than steel. They can be used for quick retrofitting of damaged structures,” he said. He has taken his graduate students to Istanbul where they conducted a major project on the strengthening design of an existing historic building using seismic isolation methods and innovative materials.

“The area of infrastructure deterioration is built on the general thrust of developing deterioration and diffusion models of how moisture moves into a material system and how it degrades,” said Buyukozturk. He pointed out how moisture in a house quickly ruins floors, beams, columns and walls. “The effect of moisture on materials is a fundamental question that is not well known, although we know that the result is deterioration.” Since the inside deterioration cannot always be seen from the surface, “that led to the related field of non-destructive testing. Without destroying or actually touching the material, we want to understand if something is going on inside.”

As a result, the group has developed non-contact methodologies, such as radar or microwave-based techniques. “We’re currently working on acoustic laser vibrometry, a very robust methodology, to check the health of buildings from a distance,” he said. “For example, we can send sound waves onto a wall and measure the vibration of the wall. If there is a crack behind the wall, the vibration behavior will be different than for an intact area. This method will probably lead to innovations where it will be possible to drive around a city with the tool and quickly check all the bridges for deterioration.” Professor Buyukozturk recently received the 2011 National ASNT Fellowship Award from the American Society of Nondestructive Testing for his work on remote detection of damage in FRP-retrofitted concrete structures using acoustic-laser vibrometry.

While moisture makes materials deteriorate, the exact mechanism is a “basic question that the classical methods cannot answer,” said Buyukozturk. To study it with new methods, he has teamed up with CEE Professor Markus Buehler to use more powerful and physics-based computational methods involving molecular dynamics modeling and atomistic simulation of materials with moisture and temperature effects. He likens the impact of atomistic simulation with a multi-disciplinary approach for opening a new era of engineering analysis to the introduction of finite element analysis methods to the engineering community four decades ago.

In 2009, Buyukozturk was elected to the Fellowship of the Royal Society of Edinburgh, Scotland’s National Academy of Science and Letters, as an “internationally distinguished researcher.” The citation mentioned his “pioneering work in computation, outstanding research and applied contributions to materials science and structures, and also his role in the advancement of engineering education.