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A new model for describing a stable cyclic stress–strain relationship under non‐proportional loading based on activation state of slip systems
Author(s) -
ITOH T.,
KAMEOKA M.,
OBATAYA Y.
Publication year - 2004
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2004.00818.x
Subject(s) - materials science , plasticity , hardening (computing) , cyclic stress , low cycle fatigue , strain hardening exponent , crystallite , slip (aerodynamics) , structural engineering , composite material , mechanics , metallurgy , thermodynamics , engineering , physics , layer (electronics)
This paper proposes a new simple model for cyclic incremental plasticity based on activation states of slip systems describing stable cyclic stress–strain relationships under non‐proportional loading. In the model, the magnitude and the direction of incremental plastic strain are estimated by (1+α f NP ) and Q , respectively. Here, α is the constant related to the dependence of material on additional hardening and f NP the intensity factor expressing the severity of non‐proportional loading. Q is the second‐order tensor describing the activation states of slip systems in polycrystalline metals and is given by the calculation using a virtual specimen. The model was examined by application to the prediction of the stable cyclic stress–strain relationship in extensive non‐proportional low cycle fatigue tests for type 304 stainless steel and 6061 aluminium alloy. The simulated results showed that the model gave a satisfactory prediction of the stable cyclic stress–strain relationship under complex non‐proportional multiaxial loadings for the two materials.