The commonly used failure models of structural members have the following shortages: 1) steel members' damaged status under different plastic deformations cannot be precisely reflected; 2) their ultimate hysteresis energy dissipation capacity is underestimated; 3) the effect of nonpeak deformation on damage of steel members cannot be indicated. As a result, study on steel structures' failure mechanism under strong dynamic loading is hindered. A modified two-parameter failure model based on deformation and energy dissipation of steel members was proposed here. The authors of the proposed model adopted a nonlinear failure model of deformation and energy dissipation derived with the low cycle fatigue theory in small plastic strain range and a linear failure model modified on the basis of Park-Ang damage model in large plastic strain range. By combining these two stages, the model could be used to describe the failure mechanism of steel members at different levels of plasticity. Low cycle fatigue tests were conducted for a group of steel members to verify the model. The results showed that the proposed model can well reflect the failure mechanism combining the effects of the first passage and the accumulated energy dissipation; it has significant theoretical and practical values for studying working states and damage mechanism of engineering structures subjected to strong wind or earthquake.
Journal of Vibration and Shock