Concepts of fracture mechanics

Course summary

This course has been prepared to meet the continuing demand for a course designed to present a clear, consistent, straight forward and unified interpretation of the basic concepts and underlying principles of Fracture Mechanics. The course begins with a brief account of some characteristic failures that could not be explained by the traditional failure criteria and of Griffith’s experiments which gave impetus to the development of a new philosophy in engineering design based on fracture mechanics. For the determination of the stress and deformation fields in cracked bodies the Westergaard method is introduced with particular emphasis on the local behaviour around the crack tip. The models of Irwin and Dugdale for the determination of the extent of plastic zone directly ahead of the crack are presented. The earliest attempt by Griffith to formulate a linear elastic theory of crack propagation will be discussed and analyzed. This is will lead us to the presentation of the theory of crack growth based on the global energy balance of the entire system and the Griffith criterion. The critical stress intensity factor criterion along with the experimental procedure for determining the plane strain critical intensity factor will be also presented and illustrated with examples. We will continue with the presentation of the J-integral in two dimensional problems and its physical intrpetation in terms of the rate of change of potential energy with respect to an incremental extension of crack. Experimental methods for the evaluation of the integral and the ASTM standard method for the determination of its critical value JIC will be described. Finally the usefulness and versatility of the strain energy density theory in solving a host of two and three dimensional problems of mixed mode crack growth in brittle and ductile fracture will be addressed. A selection of problems which cover the most important aspect of fracture mechanics is also included.

Training Objectives

The course is addressed to advanced undergraduates, Master and Ph.D. students, post-doctoral fellows, young researchers and specialists in Fracture Mechanics working in the industry. The presentations are concise and each topic contains illustrative example problems.

Prerequisites

Basic concepts of material science, continuum and structural mechanics are necessary.

Authors Curriculum

Prof. E.E. Gdoutos

Professor
Director of Laboratory of Applied Mechanics
Department of Civil Engineering
Democritus University of Thrace
GR-671 00 Xanthi, Greece

PUBLICATIONS
Author of 15 books, 132 papers in refereed journals, 80 papers in conference proceedings, and editor of 12 books.

HONORS

• Editor-in Chief of "Strain – An International Journal for Experimental Mechanics"
• President of the European Structural Integrity Society (ESIS), 2006-2010
• Chairman of the European Association for Experimental Mechanics (EURASEM), 2004-2007
• Member of the European Academy of Sciences and Arts, 2001
• Honorary Member of the Italian Group of Fracture, 2004
• Fellow of the Society for Experimental Mechanics (SEM), 2004
• Fellow of ASME, 1993
• Fellow of New York Academy of Sciences, 2001
• Member of the Honors Committee of SEM, 2005-2008
• Member of the Fellows Committee of SEM, 2006-2008
• Chairman of the Fellows Committee of SEM, 2007-2008
• Chairman of the Honors Committee of ESIS, 2004-2008
• Chairman of the Honors Committee of EURASEM, 2004-2007
• Member at Large of the SEM Executive Board, 2006-2008

DISTINCTIONS

• Member of the editorial board of the journals:
  • Theoretical and Applied Fracture Mechanics
  • Applied Composite Materials
  • Advanced Composites Letters
  • Experimental Mechanics
  • The Archive of Mechanical Engineering of Polish Academy
  • Facta Universitatis of the University of Nis
  • The Open Mechanics Journal
• President of the Society “Greek Group of Fracture,” 2003-now
• Chairman of the 16th European Conference of Fracture (ECF16), Alexandroupolis, Greece, 3-7 July, 2006
• Chairman of the 13th International Conference on Experimental Mechanics (ICEM13), Alexandroupolis, Greece, 1-6, July, 2007
• Recipient of two Fulbright research awards to visit Lehigh University (June 30-September 21, 1985) and Northwestern University (July 5-August 31, 1995)
• Recipient of the “Distinguished Visiting Professorship Award” of the Toledo University, 1992
• Listed in "Who's Who in the World-8th Edition"; "International Who's Who of Intellectuals-Seventh Edition"; "International Who's Who in Education-Third Edition"; "Five Thousand Personalities of the World"; Who’s Who in Greece (1993, 1995);“Who is Who in the World” 8th-14th editions; “Longman Who’s Who; "Who’s Who in Science and Engineering"
• Member of the Editorial Board of the “International Series on Advances in Fracture Mechanics,” WIT Press
• Guest editor of the special issues of the journals:
  • International Journal of Fracture, Vol. 79, No.2, pp. 97-208, 1996
  • Applied Composite Materials, Vol. 3, No. 5, pp. 265-353, 1996
  • International Journal of Fracture, Vol. 98, No 3-4, pp. i-xiii & 195-406, 1999
  • Facta Universitatis, Vol. 3, No 13, pp. 491-764, 2003
  • Applied Composite Materials, Vol. 12, No. 3-4, pp. 133-261. 2005
• Member of the Structures and Materials Panel of AGARD, 1992-1997
• Member of NATO Research and Technology Organization, 1997-now
• Member of the Research Board of Advisors and Fellow of the American Biographical Institute
• Head of the Department of Civil Engineering of the Democritus University of Thrace, 1987-1989
• Director of the Section of “Design and Construction of Structures,” 1983-1986 and 1993-1998
• Director of the Section of “Mechanics,” 2002-now
• Vice-Chairman of the Research Committee of the Democritus University of Thrace, 1994-1997
• Member of the "P.S. Theocaris" Foundation, 2000-now

Assoc. Professor M.S. Konsta-Gdoutos

Maria S. Konsta-Gdoutos, Associate Professor, Director of Section of Mechanics of Department of Civil Engineering of Democritus University of Thrace, holds a B.S. and M.S. in civil engineering (Democritus University of Thrace, 1987), and Ph.D. (Democritus University of Thrace 1993) in civil engineering. She has been on the faculty of the department of Civil Engineering at Democritus University of Thrace since 1993.

Her research interests include investigations into the relationships between microstructure and performance of advanced cement based materials, high performance structural materials, concrete composites and nanocomposites. Also experimental aspects of fracture mechanics focusing particularly in cement based materials. Her current research interests concentrate on the development of processing, structure, mechanical and rheological properties of high performance cementitious nanocomposites, reinforced with carbon nanotubes and nanofibers.

Dr. Konsta-Gdoutos has published over 60 articles in international journals and conference proceedings. In 2005 she was awarded a Fulbright Award to support research on rheology and mechanical properties of advanced cementious composites at Northwestern University. She is a licensed professional Civil Engineer in Greece, member of RILEM, the American Concrete Institute, and a Founding Member of ACI Hellas Chapter. Currently Dr. Konsta-Gdoutos is serving on the editorial board of STRAIN, An International Journal of Experimental Mechanics, published by Blackwell Publishing.

This course is an outcome of the ILTOF - Innovative Learning and Training on Fracture [1] project. The course is maintained free of charge by the TCN Consortium for higher education. The ILTOF project has been funded with support from the European Commission. This publication reflects the views only of the Author(s), and the Commission cannot be held responsible for any use which may be made of the information contained therein.