The following provides the interested user with additional references on material modeling.
General texts on materials
M. F. Ashby and D. R. H. Jones, Engineering Materials, Pergamon Press, 1980.
W. D. Callister, Materials Science & Engineering—An Introduction, John Wiley, 1994.
K. J. Pascoe, An Introduction to the Properties of Engineering Materials, Van Nostrand, 1978.
Plasticity
ABAQUS, Inc., Metal Inelasticity in ABAQUS.
J. Lubliner, Plasticity Theory, Macmillan Publishing Co., 1990.
C. R. Calladine, Engineering Plasticity, Pergamon Press, 1969.
Rubber elasticity
ABAQUS, Inc., Modeling Rubber and Viscoelasticity with ABAQUS.
A. Gent, Engineering with Rubber (How to Design Rubber Components), Hanser Publishers, 1992.