Griffith Cracks at the Nanoscale
Sheldon M. Wiederhorn received his B.S. Degree in Chemical Engineering from Columbia University in 1956 and his M.S. (1958) and Ph.D. (1960) from the University of Illinois, in Chemical Engineering. His first job was with E.I. Du Pont De Nemours & Co. where his research interests turned towards the study of the mechanical behavior of ceramic materials. After three years, he was hired by the National Bureau of Standards to carry out an independent research program on the mechanical behavior of glasses and ceramic materials.
At the National Bureau of Standards, now the National Institute of Standards and Technology, Dr Wiederhorn carried out a program on the mechanical reliability of brittle materials. He was one of the first to apply fracture mechanics techniques to study the fracture of ceramic materials. A consequence of his research was the development of techniques to assure the structural reliability of brittle ceramic materials. Techniques pioneered by Dr Wiederhorn and his colleagues are now used to assure the reliability of glass windows in airplanes, space-vehicles and related applications.
Dr. Wiederhorn is best known for the experiments that he developed to characterize sub critical crack growth in glasses. The results of these studies illustrate the complexity of subcritical crack growth, which consisted of stress enhanced chemical reactions between water and stressed bonds at the tips of small cracks in glass. A natural conclusion of his study was that the failure of glass was caused by the slow growth of cracks to a critical size which determined the time-to-failure.
Dr. Wiederhorn has received many awards for his research and leadership at the National Institute of Standards and Technology. These include both a Silver (1969) and Gold Medal (1982) by the Department of Commerce, and the Samuel Wesley Stratton Award, (1977) by the National Bureau of Standards. He is also a Fellow of The American Ceramic Society (1970) and has received a number of important awards for his research from the Society including the Jeppson Award (1994) for outstanding research on Ceramic Materials. He is now a Distinguished Life Member of The American Ceramic Society (1998). Dr. Wiederhorn was elected a member of the National Academy of Engineering in 1991, and in 2013, Dr. Wiederhorn was selected to present the Edward Orton, Jr. Memorial Lecture at the 115th Annual Meeting of The American Ceramic Society.
At the National Institute of Standards and Technology, Dr. Wiederhorn is now a Senior NIST Fellow Emeritus and continues to carry out a research program on the mechanical properties of ceramic materials. His current interests are to use the Atomic Force Microscope to investigate the structure of cracks in glass at the nanometer scale, and to develop ways in which the propagation of these cracks can be resisted.