Study of rotational kinematic hardening model: A general plasticity formula and model implement

Theories of the rotational kinematic hardening model are introduced in detail.this model is used to predict soil behaviors under large stress reversals by incorporatingthe rotation and intersection of isotropic hardening yield surfaces in principal stress space.during the monotonic loading, the model behaves the same as isotropic hardening model,but once stress reversals occurs, new kinematic yield surfaces will generate, then these yieldsurfaces evolve (e.g. rotate, shrink, expand, vanish etc.) obeying the rotational kinematichardening rule in the process of loading. a general plasticity formula of rotated yieldsurface or plastic potential surface in the principal stress space is given in this research,which is the basis of the rotational kinematic hardening model. it is also a very integral partto design logical procedures to determine the load mode of soil element during surfaces'evolution. new logical procedures developed by this paper have been successfully usedwithin the framework of lade-kim model; test results and model predictions showed agood consistency in stress reversal triaxial tests, using loose santa monica beach sand.source codes of logical procedures to implement the rotational kinematic hardening modelwithin the framework of lade-kim model are provided at the end of this paper to givereaders a further understanding.