Applications of hydraulic actuators for damping and isolation of structural oscillations: Fid-Bau Portal

Applications of hydraulic actuators for damping and isolation of structural oscillations

Försterling, Heino / Furtner, Peter

Apart from offering other advantageous features, hydraulic actuators are first choice if heavy loads have to be moved, lifted, or controlled. This paper presents exemplarily two applications for hydraulic systems which can help to solve problems caused by dynamic excitations and illustrate the potentials offered by electro-hydraulic control systems: On a large-scale cable-stayed bridge mock-up semi-active electro-hydraulic actuators were implemented and tested. The results impressively demonstrate the damping effect that can be achieved in conjunction with the control strategy selected. In a second large-scale mock-up, hydraulic cup-spring actuators were used to uncouple the carriageway for rail-bound vehicles from foundations (vibration isolation). These developments were carried out during CaSCo, a research project within FP 5 funded by the EC. Hydraulic actuators are the right choice for a multitude of tasks in the field of civil engineering. For example, the susceptibility to vibration of cable supported structures can be significantly reduced with the help of semi-active actuators, which are arranged in the coupling point between the rope and the structure, in conjunction with a suitable control strategy. This was demonstrated on a large-scale mock-up of a cable-stayed bridge. When compared with active concepts, the energy requirement is much lower. In another application, hydraulic spring elements were developed for the isolating the vibration on rail carriageways, which allow damping effects without impairing the isolation effect. Another essential advantage of these hydraulic spring elements is the possibility of re-adjusting the natural frequency.