抄録
For elastic-plastic stress analyses, the stress-strain characteristic is one of the most fundamental properties of material. Though S-S curve expressed by multiple linear lines can be easily available for FEM codes, S-S curve expressed as an analytic function is more useful for theoretical analyses. However, formulation of S-S curve using few measured data may be not studied enough. For the Needleman S-S curve, an approximate estimation procedure, using Newton method solving two equations comprised by yield stress and tensile strength, is presented. And two application studies, plastic buckling stress of short column and collapse pressure in the elastic-plastic zone, are performed. The studies show that the estimate of S-S curve can be used for accurate calculation under both stress states, since the failure strengths calculated agree well with ones obtained by experiment.
