Int.J.Plast. 7, 781-802, 1991
A.J. Svobodnik, H.J. Böhm and F.G. Rammerstorfer
Institute of Lightweight Structures and Aerospace
TU Wien, Vienna, Austria
Based on analytical considerations by Dvorak and Bahei-el-Din, a 3/D finite
element material law has been developed for the elastic-plastic analysis
of unidirectional fiber-reinforced metal matrix composites.
The material law described in this paper has been implemented in the
finite element code ABAQUS via the user subroutine UMAT.
A constitutive law is described under the assumption that the fibers
are linear-elastic and the matrix is of a von Mises-type with
a Prager-Ziegler kinematic hardening rule.
The uniaxial effective stress-strain relationship of the matrix in the plastic
range is approximated by a Ramberg-Osgood law, a linear hardening rule or
a nonhardening rule.
Initial yield surfaces of the matrix material and for the fiber reinforced
composite are compared to show the effect of reinforcement.
Implementation of this material law in a finite element program is shown.
Furthermore, the efficiency of substepping schemes and stress corrections
for the numerical integration of the elastic-plastic stress-strain relations
for anisotropic materials are investigated.
The results of uniaxial monotonic tests of a boron/aluminum composite are
compared to some finite element analyses based on micromechanical
Furthermore, a compelete 3/D analysis of a tensile test specimen made of
a silicon-carbide/aluminum MMC and the analysis of an MMC inlet inserted
into a homogeneous material are shown.