Peer-Reviewed Journal Details
Mandatory Fields
Agius, D;Kourousis, KI;Wallbrink, C
2018
August
International Journal Of Mechanical Sciences
A modification of the multicomponent Armstrong-Frederick model with multiplier for the enhanced simulation of aerospace aluminium elastoplasticity
Published
0 ()
Optional Fields
MEAN STRESS-RELAXATION KINEMATIC HARDENING MODEL LOW-CYCLE-FATIGUE CONSTITUTIVE MODEL INTRAGRANULAR BACKSTRESSES PLASTICITY MODELS STAINLESS-STEEL DEFORMATION BEHAVIOR ALLOY
144
118
133
The Multicomponent Armstrong Frederick (AF) model with Multiplier (MAFM) has demonstrated high simulation accuracy for uniaxial and multiaxial loading conditions for a number of different materials. In this study the MAFM model is modified to improve the phenomenological modelling of aerospace aluminium alloys 7075-T6 and 7050-T7451 under uniaxial constant and variable amplitude loading. In order to recognise the experimentally observed strain amplitude dependency of mean stress relaxation rate, the coefficient of the linear kinematic back stress was modified from a constant to a strain amplitude dependent dynamic term. This modification improved the mean stress relaxation capability of the MAFM model. Additionally, the hysteresis loop evolution has been enhanced via further modification of the MAFM model by improving the monotonic stress-strain evolution of the initial loading branch of cyclic load cases by separating the kinematic backstress coefficients into two parts, the contributions from cyclic and monotonic micro-mechanisms. The monotonic coefficients were allowed to decay with continued cycling, which captured the monotonic to cyclic transition of stress-strain development. Finally, the experimentally observed reversibility of the monotonic stress-strain evolution has been also incorporated successfully through the introduction of a decaying strain range memory parameter, which improved the variable amplitude hysteresis loop evolution. Overall, the modified MAFM model has been successful in improving simulation accuracy of the cyclic elastoplastic response exhibited by both aluminium alloys examined.
OXFORD
0020-7403
10.1016/j.ijmecsci.2018.05.036
Grant Details