Title of article :
Cyclic behavior modeling of a tempered martensitic hot work tool steel
Author/Authors :
V. VELAY، نويسنده , , G. BERNHART، نويسنده , , L. Penazzi، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2006
Pages :
38
From page :
459
To page :
496
Abstract :
In this paper, a non-unified elasto-viscoplastic behavior model based on internal state variables, is investigated in order to describe the thermo-mechanical stress–strain fatigue response of 55NiCrMoV7 tempered martensitic steels (AISI L6). This model considers a quadratic yield criterion to define the elasticity domain. It allows the determination of two inelastic strain mechanisms resulting from two stress states which can be related to the typical continuous cyclic softening of the tempered martensitic steels. This cyclic softening is reproduced through an isotropic component (drag stress). A memory effect is also introduced to take into account the influence of the plastic strain range on the amount of the cyclic softening. The kinematic component (back stress) of the model allows the description of complex load conditions to which tool steels are subjected. Strain recovery (Baushinger effect), time recovery terms (cyclic behavior including tensile dwell times) and ratcheting effects are considered. The numerical implementation is addressed and two integration methods (explicit and implicit) of the constitutive equations are presented. Moreover, the identification methodology of the model parameters from only two sets of experimental data is presented; the coefficients of the kinematic and isotropic parts are determined successively. The main difficulty consists in reaching a good description both of the cyclic behavior for different strain rates and the ratcheting effect. Last, a validation stage of the three dimensional model is investigated from low cycle fatigue tests performed on different notched specimens.
Keywords :
Numerical simulation , tempered martensitic steels , Stress–strain modeling , Constitutive model identification
Journal title :
International Journal of Plasticity
Serial Year :
2006
Journal title :
International Journal of Plasticity
Record number :
1257229
Link To Document :
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