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01/03/2008 08:00:00

Ortiz Wins Inaugural Prize in Solid Mechanics

PASADENA, Calif.--Michael Ortiz, the Hayman Professor of Aeronautics and Mechanical Engineering at the California Institute of Technology, is the first winner of the Rodney Hill Prize in Solid Mechanics. The newly established international prize, which will be awarded every four years, is also the first of its kind in this field.

The Hill Prize, sponsored by scientific publisher Elsevier Limited and awarded under the auspices of the International Union of Theoretical and Applied Mechanics, will be bestowed in August 2008 at the Union's 22nd Congress in Adelaide, Australia. Ortiz will receive a plaque and $25,000.

Ortiz is being recognized for several contributions within the past decade, among them a new method for computing plastic deformation. His Caltech colleague, mechanics and materials science professor Kaushik Bhattacharya, describes Ortiz's formulation as "a combination of the cutting edge of mechanics and the cutting edge of mathematics." Plastic deformation reshapes a material without breaking it, like stretching a piece of Silly Putty, in incremental steps. Ortiz developed the incremental variational principle, which allows the computation of plastic deformations as they proceed. "These processes immediately affect applications ranging from the most mundane engineering to the kind of sophisticated things that go into modern manufacturing," says Bhattacharya.

Another of Ortiz's contributions, which he calls the quasi-continuum method, was developed in collaboration with Rob Phillips, professor of applied physics and mechanical engineering at Caltech, while they were both at Brown University. The method forms a bridge between the way engineers describe mechanical properties of materials at the scale of the atom and the way they describe these properties at a larger scale.

Atomistic physics, at the scale of nanometers, applies quantum mechanics to the study of how energy interacts with matter. At the scale of micrometers, continuum mechanics treats an object's substance, or matter, as uniformly changing, and a different set of physical rules applies. The crux of the problem, says Bhattacharya, is that "the way we describe the physics at the atomistic scale is different from how we describe it at the continuum scale. But the properties you observe at the larger scale are the sum total of all the properties at every scale leading up to it. This formula unites the scales.

"The quasi-continuum method is the first rigorous way of approaching this problem," Bhattacharya notes. "Most approaches are ad hoc. This is a method that goes down to fundamental physics and mathematics to do it in a seamless manner. It has beautiful mathematics and physics in it and has a really fantastic computational structure. It was so far ahead of its time when they started doing this around 10 years ago. When you see it you say, 'That's exactly the way to do it!'"

Ortiz says he feels greatly honored to win the prize because of the recognition that it brings to theoretical and computational mechanics. "I have always enjoyed working closely with mathematicians, physicists, and chemists, and I hope that this prize will underscore the importance of those collaborations," he says. "I am greatly indebted to my brilliant students, who have been an inexhaustible source of energy and enthusiasm; to my colleagues and collaborators over the years, from whom I have learned most of what I know; and to my family for their constant and unconditional support."

According to Bhattacharya, the Hill Prize is intended to be the first highly and internationally visible prize for all of mechanics. Its analogue for fluid mechanics, the Batchelor Prize, was created at the same time and awarded to Caltech alumnus Howard Stone, the Joseph Professor of Engineering and Applied Mathematics at Harvard University.

About Ortiz's achievement Bhattacharya says, "I was not surprised that he won, because Michael is that caliber a person. He is extraordinarily creative. Every time you talk to him he has a new idea, and his ideas are really radical departures from what people have done in the field."

Written by elisabeth nadin