Multiaxial creep-fatigue under anisothermal conditions

Because creep-fatigue is mainly studied in uniaxial tension, it is shown he re how to proceed to perform both experiments and calculations under multia xial loading and when the temperature varies both in time and space. The co nstitutive equations used are those of elasto-visco-plasticity coupled or n ot, to damage, with isotropic and kinematic hardening. It is shown that the unified damage law first proposed for ductile failure and then for fatigue may also be applied to multiaxial creep-fatigue interactions with a new ex pression for the damage threshold. The procedure for the identification of material parameters is described in detail. Finally, it is shown that the u ncoupled calculation procedure, where damage is calculated as a post-proces sing of an elasto-visco-plastic computation, gives satisfactory results in comparison to the fully coupled analysis; the latter being more accurate bu t very expensive in computer time.