Abstract

Dr. Robert Ritchie
Materials Sciences Division, Lawrence Berkeley National Laboratory
Chair, Department of Materials Science & Engineering
University of California, Berkeley

"Fracture in Bone: Role of Aging, Drugs and Disease "

Monday March 17, 2008
4:00 - 5:00 pm
Chem Eng Room 005

ABSTRACT:

The age-related deterioration of both the fracture properties and the architecture of “hard” mineralized tissue, such as bone, coupled with increased life expectancy, are responsible for increasing incidences of bone fracture in the elderly segment of the population.

Synchrotron x-ray computed tomography image showing osteoporotic human trabecular bone

In order to facilitate the development of effective treatments that counter this elevation of the fracture risk, an understanding of how fracture properties degrade with age is essential. In this talk, the origins of the toughness of human cortical bone (and dentin, a primary constituent of teeth and simple analog of bone) are examined by considering the salient micro-mechanisms of failure over a broad range of characteristic dimensions from molecular to macroscopic length-scales. It is argued that although structure at the nanoscale is important, it is microstructural features at the scale of one to hundreds of microns that are most important in determining fracture risk. It is further shown that biological aging, disease states, and certain therapeutic treatments, e.g., steroids, can cause deterioration in “bone quality” which markedly raises this fracture risk, principally by affecting the toughening mechanisms over a broad range of dimensions.

BIO:

Robert O. Ritchie is the H.T. & Jessie Chua Distinguished Professor of Engineering, and Chair of the Department of Materials Science & Engineering at the University of California, Berkeley. He is also Senior Faculty Scientist in the Materials Sciences Division of the Lawrence Berkeley National Laboratory, and a member of the University of California San Francisco/University of California Berkeley Bioengineering group.

Dr. Ritchie received a B.A. degree (double first class honors) in physics and metallurgy in 1969, the M.A. and Ph.D. degrees in Materials Science in 1973, and the Doctor of Science (Sc.D.) degree in 1990, all from Cambridge University. Following periods as the Goldsmith's Research Fellow in Materials Science at Churchill College, Cambridge (1972-1974) and as a Miller Research Fellow for Basic Research in Science at the University of California in Berkeley (1974-1976), he joined the faculty in Mechanical Engineering at M.I.T. where he became the Class of 1922 Associate Professor in 1979. In 1981, he returned to Berkeley where he has been Professor of Materials Science since 1982; he was also Deputy Director of the Materials Sciences Division at the Lawrence Berkeley Laboratory from 1990 to 1994, and Director of the Center for Advanced Materials there from 1987 to 1995. He has served as a consultant for both government and industry, including such companies as Alcan, Allison, Boeing, Chevron, Exxon, Garrett Turbine, General Electric, General Motors, Grumman Aerospace, Instron, JPL, Northrop, Rockwell, Teledyne, Westinghouse and numerous legal firms. He has also acted as a consultant in the medical field to numerous companies, including Baxter, Cordis, Carbomedics, Edwards, Guidant, Shiley, and St. Jude Medical on the mechanical integrity of cardiac valves, endovascular stents and other prosthetic devices. In addition, he has served as a member of several National Research Council Committees including "Advanced Space Technology" and "Small Spacecraft Technology".

Dr. Ritchie is well known for his research in the fields of materials science, fracture mechanics and particularly fatigue, having authored or co-authored over 550 papers and edited 19 books in the technical literature (he is one of ISI's Highly Cited Authors in Materials Science). He is a Member of the National Academy of Engineering in the U.S. and a Fellow of the Royal Academy of Engineering (FREng) in the UK, and has been the recipient of several other awards, including the Journal of Engineering Materials & Technology Best Paper Award from the American Society for Mechanical Engineers (ASME) in 1979, the Marcus A. Grossmann Award from the American Society for Metals (ASM) in 1980, the Most Outstanding Scientific Accomplishment Award from the U.S. Department of Energy in Metallurgy in 1982 and in Ceramics in 1989, the Champion H. Mathewson Gold Medal from the Metallurgical Society of AIME (TMS) in 1985, the George R. Irwin Medal from the American Society for Testing and Materials (ASTM) in 1985, the E-9 Award for the Best Presented Paper on Fatigue from ASTM in 1986, the Curtis W. McGraw Research Award from the American Society for Engineering Education (ASEE) in 1987, the Rosenhain Medal from the Institute of Materials (London) in 1992, the Structural Materials Distinguished Materials Scientist/Engineer Award from TMS in 1996, the ASTM Journal of Testing and Evaluation Award for Most Outstanding Article in 1998, the Nadai Medal from ASME and the ASTM Fatigue Lectureship in 2004, the Wöhler Medal from European Structural Integrity Society in 2006, and the A. A. Griffith Medal from the Institute of Materials (London) in 2007. He was the Van Horn Distinguished Lecturer (Case Western Reserve University) in 1997, a Southwest Mechanics Lecturer in 1997-98, RPI's IBM Distinguished Lecturer in 2004 the Arthur Newell Tablot Lecturer in Theoretical and Applied Mechanics (University of Illinois at Urbana-Champaign) in 2006, and the Dow Lecturer at Northwestern University in 2007. He was also named as one of America's Top 100 Young Scientists by Science Digest magazine in 1984, chaired the Gordon Conference on Physical Metallurgy in 1992, and was an Honorary Visiting Professor at the University of Plymouth (UK). He was President (1997-2001) and is an Honorary Fellow of the International Congress on Fracture. He is also a TMS Fellow, a Fellow of the Institute of Materials (FIMMM), the Institute of Physics (FInstP), and the American Society for Materials, and a chartered engineer (CEng.) in the UK.

[return to seminar schedule]