*Computational Mechanics for the Twenty-First Century*
(Ed. B.H.V.Topping), pp. 145-164, 2000

### FINITE ELEMENT METHODS IN MICROMECHANICS OF COMPOSITES AND
FOAM MATERIALS

F.G. Rammerstorfer and H.J. Böhm

Institute of Lightweight Structures and Aerospace
Engineering,

TU Wien,
Vienna, Austria

**Abstract** -
Constitutive equations and the corresponding material properties used in
structural analyses are in most cases obtained from experimental studies
performed on specimens which are large enough to represent the effective,
i.e. overall, material behaviour.
In the case of multi-phase materials, this effective response typically is
determined by the topology and geometry as well as the thermo-mechanical
material and interfacial behaviour at lower length scales, i.e. meso-,
micro- and submicro-scales.
The present contribution gives some examples of how finite element methods
can be used for studying problems related to the thermo-mechanical behaviour of
two groups of inhomogeneous materials: metallic materials that can be treated
as ductile matrix composites and highly porous metals.
As representatives of the former group high speed tool steels, which
consist of a martensitic steel matrix that contains carbidic particles,
are studied by different finite element based approaches and fibre
reinforced metal matrix composites are discussed.
With regard to highly porous metals the uniaxial compressive and tensile
behaviour of a syntactic foam as well as the fracture behaviour of an open
cell metallic foam are modelled.

(hjb,000914)