Sliding Mode Control for Semi-Active Damping of Vibrations Using on/off Viscous Structural Nodes

Structural vibrations have adverse effects and can lead to catastrophic failures. Among various methods for mitigation of vibrations, the semi-active control approaches have the advantage of not requiring a large external power supply. In this paper, we propose and test a sliding mode control method for the semi-active mitigation of vibrations in frame structures. The control forces are generated in a purely dissipative manner by means of on/off type actuators that take the form of controllable structural nodes. These nodes are essentially lockable hinges, modeled as viscous dampers, which are capable of the on/off control of the transmission of bending moments between the adjacent beams. The control aim is formulated in terms of the displacement of a selected degree of freedom. A numerically effective model of such a node is developed, and the proposed control method is verified in a numerical experiment of a four-story shear structure subjected to repeated random seismic excitations. In terms of the root-mean-square displacement, the control reduced the response by 48.4-78.4% on average, depending on the number and placement of the applied actuators. The peak mean amplitude at the first mode of natural vibrations was reduced by as much as 70.6-96.5%. Such efficiency levels confirm that the proposed control method can effectively mitigate vibrations in frame structures.

Automated summary

The paper proposes and tests a sliding mode control method for semi-active vibration mitigation in frame structures. Control forces are generated in a dissipative manner using controllable structural nodes. Numerical experiments on a four-story shear structure showed an average reduction of vibration response by 48.4-78.4% depending on the number and placement of actuators. The proposed control method effectively mitigates vibrations in frame structures, reducing the peak mean amplitude at the first mode by up to 70.6-96.5%.