繰返し軟化の温度変動履歴依存性を考慮した改良9 Cr-1 Mo鋼に対する統一形非弾性構成式の定式化

The present study is concerned with the formulation of a unified inelastic constitutive model describing the behavior of cyclic softening under temperature variations. For this purpose, we first examine the behavior of isotropic and kinematic hardening variables based on the results of cyclic experiments conducted by us under several constant temperatures and temperature variations. The results show that the cyclic softening is induced mainly by the kinematic hardening variables. The variation in the degree of cyclic softening with temperature variation is also discussed. Based on this information, the evolution equations of the kinematic hardening variables are formulated. By incorporating these equations into the unified model proposed previously by us, a final constitutive model is established. Monotonic, creep and cyclic tests under constant temperatures and temperature variations are simulated in order to evaluate the validity of the proposed model. The results show that the model can predict a wide range of inelastic behavior of this material with relatively high accuracy.