Rain\wind induced vibrations of stay cables

Studenteropgave: Speciale (inkl. HD afgangsprojekt)

  • Claus Gadegaard
  • Jesper Jensen
4. semester, Bygge- og anlægskonstruktion, Kandidat (Kandidatuddannelse)
Rain/wind induced vibrations for the most severe natural load on cables used as support will be examined. The theory behind rain/wind induced vibrations on stay-cables will be outlined, based on the present available literature. A numerical quasi-static multi degree of freedom model of a stay cable is developed and a load model is established to implement the rain/wind induced aeroelastic loading on the cable. Four different types of damping mechanisms are considered for mitigation of the rain/wind induced vibrations. Active control of the axial forces by an actuator at the lower cable support point is initially considered. The control in the remaining three types is based on a perpendicular connection between the damping mechanism and the cable, at a constant distance away from the lower cable support point. Here, passive viscous damping is introduced where the damping coefficient is tuned to the first in-plane cable mode of vibration. Semi-active MR-damping is introduced with the objective to reduce the vibration response from passive viscous control. Finally, active control by use of the pole placement method is analysed. Furthermore, the active control by pole placement is supported by integral control in order to remove a static offset of the cable displacement from the applied mean wind. Special attention is brought to evaluate the relative effectiveness of the considered damping mechanisms. Practical considerations, general theory, and control algorithms with regard to the mentioned control strategies are handled.
SprogEngelsk
Udgivelsesdato2009
Antal sider58
Udgivende institutionAalborg Universitet
ID: 17728335