Arch.Appl.Mech. 69, 727-750, 1999
V.V. Silberschmidt°, F.G. Rammerstorfer¹,
E.A. Werner°, F.D. Fischer²
and P.J. Uggowitzer³
°Lehrstuhl A für Mechanik,
TU München, Garching, Germany
¹Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria
²Institute of Mechanics, Montanuniversität Leoben, Austria
³Institut für Metallforschung und Metallurgie,
ETH Zürich, Zurich, Switzerland
The paper analyses specific features of the response of two-phase materials
with different thermomechanical properties of the phases to purely
It is shown that even without mechanical loading both shakedown and
ratchetting regimes are possible.
A short review is given of the phenomena and various models of shakedown
and ratchetting under cyclic thermomechanical loading.
Three structural models for the description of a special two-phase material,
namely the duplex steel, under purely thermal loading are discussed;
a simple two-bar model, a composite cylinder model and micromechanical finite
element models with duplex topologies.
These models account for different features of the deformation process during
thermal cycling and are used as basis for the analysis of thermal
Results of numerical simulations are presented for various material conditions
and modelling schemes.
Conditions for material immanent ratchetting are derived and verified by numerical experiments. It is shown that a temperature-dependence of the yield stresses of the two phases, which exhibits an intersection of the corresponding curves within the temperature interval of the cyclic thermal load, enforces this sort of ratchetting, lacking intersection of the yield stress-temperature curves indicates, on the other hand, a lesser or lacking tendency for material immanent ratchetting. Comparisons with results of laboratory experiment are also presented, and the tendencies derived from the micromechanical models are verified.