Dimitrios S. Sophianopoulos

The effect of joint flexibility on the free elastic vibration characteristics of steel plane frames

Abstract The present work offers a simplified approach for establishing the effect of joint flexibility on the free vibration characteristics of steel plane frames. Based on the beam-to-column model of Eurocode 3, the presented analysis shows that within the elastic range and under certain combinations of the parameters involved, a transition to a higher vibration mode may occur, a finding of great importance for structural design purposes. Numerical results of an L-shaped steel frame, considered either rigid or semi-rigid, in tabular and graphical form, reveal the pronounced effect of the joint’s stiffness and its specific role especially on higher vibration modes, implying that the actual flexible joint behavior should be accounted for, even in the elastic range.

A New Rate-Dependent Constitutive Model of Superelastic Shape Memory Alloys and Its Simple Application in a Special Truss Moment Frame Simulation

In this work, a new constitutive model of the behavior of shape-memory alloys is presented, based on earlier models, showing a very good agreement with the existing experimental results. A simple approximate application concerning the use of these alloys modelled as dissipation devices in a special truss-moment frame is demonstrated. The results obtained are considered sufficiently encouraging as a motivation for the ongoing work.