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321 Thurston Hall
Cornell University

Ithaca, NY 14853

Phone: 607/255-8818

S. Leigh Phoenix

Professor

B.Sc.Eng. 1967 (Guelph)

M.Sc.Eng. 1968 (Guelph)

Ph.D. 1972 (Cornell)

Professional Biography

After receiving his Ph.D., Phoenix worked for two years as a senior research associate at Fabric Research Laboratories, in Dedham, Massachusetts, before joining the Cornell faculty in 1974. He is associated with the Materials Science Center. He spent his first sabbatical year at the Lawrence Livermore National Laboratory doing research on the failure of composites (1981-82), and a second sabbatical leave at the University of Surrey in England (fall 1988). In 1983 Phoenix received the Fiber Society Award for Distinguished Achievement in Basic or Applied Fiber Science, and in 1992 he won the American Society for Testing and Materials' Harold DeWitt Smith Award. He is a member of the American Physical Society, the Fiber Society, and the American Society for Composites.

Research Interests

Our research involves theoretical and experimental studies of the long-term reliability of fibrous composites under high stresses. Examples of applications include cables, pressure vessels, rocket-motor casings, centrifuges, and flywheels fabricated from Kevlar 49 or graphite fibers in an epoxy matrix. In these applications high reliability over long time periods is a key concern, especially in view of the fact that real-time evaluation on large numbers of specimens is prohibitive. Thus, efforts directed toward the development of micromechanical and statistical models of the failure process are coupled with critical-fracture experiments on the microscale. Specific areas of interest are:

Creep-Rupture Models for Polymer, Metal, and Ceramic-Matrix Fibrous Composites: interactions between fiber fracture statistics and matrix creep laws to determine exponents and scalings of fracture distributions

Computational Methods for Calculating Stress Fields around Arrays of Interacting Cracks: development of influence field approaches to rapidly calculate stresses in materials with many cracks

Fast Influence Function Techniques for Calculating Stresses around Fiber Breaks in Fibrous Composites: development of influence function techniques for calculating fiber and matrix stresses under viscoelastic deformation of the matrix

Ballistic impact into fibrous materials: development of models and scalings to understand impact dynamics and stresses during penetration of projectiles into body armor

Compressive failure of unidirectional composite layers: development of local buckling failure in fiber clusters using influence functions

Selected Publications

  • Beyerlein, I.J., S. L. Phoenix and R. Raj. 1998. Time evolution of stress redistribution around arbitrary arrays fiber breaks in a composite with viscous and viscoelastic matrices. Int. J Solids and Structures 35: 3177-3211.
  • Burton , J.K and S. L. Phoenix. 2000. Superposition method for calculating singular stress fields at kinks, branches and tips in multiple crack arrays. Int. J. Fracture 102: 99-139.
  • Phoenix , S.L and I. J. Beyerlein. 2000. Statistical Strength Theory for Fibrous Composite Materials. Chapter 1.19, in Vol. 1 of Comprehensive Composite Materials , (6 volumes), (A. Kelly and C. Zweben, editors-in-chief; T.W. Chou, Volume 1 ed.) Pergamon (Elsevier Science).
  • S. L. Phoenix, S.L. and I. J. Beyerlein. 2000. Distributions and size scalings for strength in a 1D random lattice with load redistribution to nearest and next-nearest neighbors. Physical ReviewE 62 : 1622-1645.
  • Phoenix , S.L and P. K. Porwal. 2003. A new membrane model for ballistic impact response and V 50 performance of multi-ply fibrous systems. Int. J. Solids and Structures 40: 6723-6765.
  • Mahesh, S and S. L. Phoenix. 2004. Absence of a tough-brittle transition in the statistical fracture of unidirectional composite tapes under local load sharing. Phys Rev. E . 69: 026102 (23 pages).
  • Mahesh, S and S. L. Phoenix. 2004. Lifetime distributions for unidirectional fibrous composites under creep-rupture loading, International Journal of Fracture 127 : 303–360.
  • Bai, J. and S. L. Phoenix. 2004. Compressive failure model for fiber composites by kink band initiation from obliquely aligned, shear-dislocated fiber breaks. Int. J. Solids Structures , in press.