Abstract
Alan Cottrell had a unique ability to impact the metallurgical/materials research community via his fundamental approaches at various length scales and by providing micromechanistic approaches to fracture in crystalline materials, culminating in the macro-mechanics of large-scale engineering structures. His concepts/techniques/analyses have been successfully applied to a range of structural materials and are being applied to an ever-increasing range of more complicated materials systems, ranging from ferrous-based crystalline systems to amorphous metals and biological systems. The field of Modern Fracture Mechanics requires an increasingly complex set of experimental and computational tools to capture material deformation, damage accumulation and failure across multiple size and time scales and builds directly from some of the earliest works and desires of Sir Alan, as reviewed herein.
Acknowledgements
An early personal contact with Sir Alan when he was Master of Jesus College, University of Cambridge is acknowledged from when the author was a NATO/NSF postdoctoral scholar in the Department of Metallurgy, Cambridge University, in 1983–1984. A memorable high table dinner with Sir Alan presiding was spent discussing various technical topics, his service to the government in various capacities and the important contributions of the Knott Fracture Group in Cambridge. Memories of a gracious and humble host and his natural ability to make a guest feel comfortable in his presence remain with me. Subsequent contact with Sir Alan during my sabbatical in 2003–2004 as Overseas Fellow at Churchill College in the Department of Materials Science and Metallurgy, Cambridge University, regarded comments related to the use of the Kelly, Tyson, Cottrell concept applied to begin to rationalize the Intrinsic Plasticity or Brittleness of Metallic Glasses in the paper co-authored with Professors WH Wang and AL Greer cited as reference number 25 above. The author also gratefully acknowledges support by NSF, AFOSR, ONR, ARO, DARPA, NASA, NIH, DTRA, Ohio Third Frontier and Ohio Board of Regents, along with various industrial support and collaborators over the years. Present support for the design of high density and high toughness metallic glasses is being provided by DTRA as part of a collaborative team led by UVa, CMU and CWRU, with other support on size scale and pressure effects on metallic glasses by ARO-W911NF-12-1-0022. Other ongoing supported work on sensitization of 5xxx aluminium alloys is funded by ONR-N00014-11-1-0406, while that on implantable electrodes for functional electrical stimulation has been funded by NIH-NINDS-NS-041809 and NIH-NBIB-EB-001740.