Second-order plastic-hinge analysis of 3-D steel frames including strain hardening effects

A strain hardening rule for 3-D plastic-hinges is proposed in this paper. The linear strain hardening law is modelled as the expanse of the yield surface by two parameters: the effective strain and the plastic modulus. The definition of the effective strain and the method of fixing the value of plastic modulus are described. A conventional second-order elastic–plastic approach accounting for the above hardening rule is presented next. This algorithm has been fully implemented in a computer program. Finally, as the numerical examples, two three-dimensional steel frames are analyzed by the proposed technique.