구조용 강재의 Two-Surface 소성모델 = Two-Surface Plasticity Models of Structural Steel

다국어 초록 (Multilingual Abstract)

The task of plastic theory is twofold: first, to set up relationships between stress and strain which describe adequately the observed plastic deformation of metals, and second, to develop techniques for using these relationships in the study of the mechanics of metal forming processes, and the analysis and design of structures. One of the major problems in the theory of plasticity is to describe the behavior of work-hardening materials in the plastic range for complex loading histories. This can be achieved by formulating constitutive laws either in the integral or differential forms. To adequately predict the response of steel members during cyclic loading, the hardening rule must account for the fearutes of cyclic stress-strain behavior. Neither of the basic isotropic and kinematic hardening rule are suitable to describe cyclic stress-strain behavior although a kinematic hardening rule describes the near linear portions of the stabilized hysteresis loops and there is a limited expansion of the yield surface as predicted by the isotropic hardening rule.
According to the existence of a yield surface and a bound surface which represents the maximum stress state the material ever experienced, the plasticity models including two surface model are surveyed. This paper is concerned with the improvement of a plasticity model of the two-surface type for structural steel based on experimentally observed features of steel specimens tested under cyclic nonproportional loading condition at room temperature.