Abstract
Plasticity in steel is characterized by an appreciable amount of plastic flow which precedes strain-hardening. This study is devoted to an evaluation of the modulus in shear of yielded steel plates in the plastic-flow and strain-hardening range at the instance of torsional buckling. Plastic strain is assumed to occur by the slip deformation which depends on Tresca's yieled criterion. Torsional buckling of steel plates uniformly compressed in one direction is examined. Difference of buckling curve between author's result and other researchers' one is shown in the viewpoint of buckling stress. Author's result fairly agree with test result already published.
