Dynamic Crack Propagation in Particle Reinforced
Nanocomposites and Graded Materials
by
Arun Shukla
Simon Ostrach Professor and Chairman
Department of Mechanical Engineering
University of Rhode Island
Kingston, RI 02881
Abstract
An experimental investigation has been conducted to evaluate the mechanical properties of novel materials fabricated using nano and micron sized particles in polymer matrix. Unsaturated polyester resin specimens embedded with small loadings of 36 nm average diameter TiO2 particles were fabricated using a direct ultrasonification method to study the effects of nanosized particles on nanocomposite bulk mechanical properties. The ultrasonification method employed produced nanocomposites with excellent particle dispersion as verified by TEM. The presence of the particles had the greatest effect on fracture toughness. Both static and dynamic fracture toughness showed marked improvements with addition of small volume fractions (up to 1%)of nano particles. Experiments were also conducted to study the complete history of dynamic crack propagation from initiation to crack branching in nano composites.
A transient analytical study has also been conducted to investigate dynamic fracture in functionally graded materials (FGMs) that have been prepared using micron sized particles. Asymptotic expansion of the displacement, strain and stress field for transient crack propagation in FGMs has been developed. The analysis revealed that the crack-tip stress fields retain the inverse square root singularity and only the higher order terms in the expansion are influenced by the material non-homogeneity. Experiments have also been conducted to study dynamic crack propagation in these materials.
Arun Shukla
Phone: 401-874-2283 Fax:401-874-2355
shukla@egr.uri.edu
Ph.D. - University of Maryland, 1981
M.S. - University of Maryland, 1978
B.S. - Indian Institute of Technology, 1976
Research and Teaching Interests
Experimental and Theoretical Mechanics; Optical Methods; Fracture Mechanics; Composite Materials; Nano Materials; Wave Propagation; Impact Mechanics; and Elasticity.
Professional Experience
Simon Ostrach Professor, Endowed Chair, (2000-Present), Interim Dean, College of Engineering (2002);Department Chairman, URI (2001-Present); Distinguished Engineering Professor, URI (1997-2000); Professor, URI (1988-Present), Visiting Professor, Texas A&M University, California Institute of Technology and IIT Kanpur, India, sabbatical leave (1994-95); Visiting Professor, Indian Institute of Technology, Kanpur, sabbatical leave (1987-1988), Assistant/Associate Professor (1981-1988), Department of Mechanical Engineering and Applied Mechanics, University of Rhode Island; Instructor, Department of Mechanical Engineering, University of Maryland (1979-1981); Research Assistant, Department of Mechanical Engineering, University of Maryland (1977-1979); Design Engineer, Voltas Ltd., India (1976).
Professional Memberships and Activities
President Society for Experimental Mechanics (2002-2003);President Elect Society for Experimental Mechanics (2001-2002); Vice-President, SEM (2000-2001); Technical Editor, International Journal, Experimental Mechanics (1997-2000); Associate Technical Editor; Experimental Mechanics (1987-1996); Associate Technical Editor International Journal, Lasers and Optics in Engineering (1997-Present); Member Editorial Advisory Board, Key Engineering Materials, Trans Tech Publications (1997-Present); Member Editorial Board, International Journal, Lasers and optics in Engineering, (1993-19960; Member, Executive Board SEM (1994-1996); Chairman, Technical Divisions Council, SEM,(1995-1996); Chairman, Fellow's Committee, SEM,1996-1997; Chairman Fracture Mechanics Committee, ASME,1992-1995; Chairman, Fracture and Fatigue Division, SEM, 1992-1993; Member, Honors Committee, SEM 1991- 1994; Member, Women in Engineering Program and Advocates Network, ASEE, AAM, ASME, and SEM.
Awards, Distinctions and Honorary Memberships
Elected Fellow of the American Academy of Mechanics, 2001; Elected Fellow of the American Society of Mechanical Engineers, 1996; Elected Fellow of the Society for Experimental Mechanics, 1993; B. J. Lazan Award for Outstanding Technical Contributions to Experimental Mechanics, Society for Experimental Mechanics, 2002; Delivered The Taylor Memorial Lecture at The Indian National Congress of Applied Mechanics, India 2001. Received Educator of the Year – M. M. Frocht Award, Society for Experimental Mechanics, 2001.University of Rhode Island Research Achievement Award (2001); Keynote Lecture at the International Conference on Advanced Technology in Experimental Mechanics, July 1999, Ube City, Yamaguchi, Japan; Keynote address at the 43rd Congress of Indian Society of Theoretical and Applied Mechanics, Coimbatore, 1998. Vincent E. and Estelle Murphy Faculty Excellence Award, College of Engineering, URI, 1998; ASTM Outstanding Paper Award J. of Testing and Evaluation, 1998. Seth Memorial Lecture at ISTAM, India 1997; The University of Rhode Island's Scholarly Excellence Award, 1995; Albert E. Carlotti Faculty Excellence Award, College of Engineering, URI, 1990.
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