000022634 001__ 22634
000022634 005__ 20170724144658.0
000022634 04107 $$aeng
000022634 046__ $$k2017-07-04
000022634 100__ $$aMacdonald, John
000022634 24500 $$a3DOF galloping analysis based on quasi-steady theory with reference to the aerodynamic stiffness

000022634 24630 $$n7.$$p7th European and African Conference on Wind Engineering 
000022634 260__ $$bl'Association pour l'Ingénierie du Vent
000022634 506__ $$arestricted
000022634 520__ $$2eng$$aGalloping has been a continuous problem for power transmission lines, bridge towers and cable stays. Although the classical Den Hartog criterion can provide reasonable predictions of galloping and is still being used in a variety of practical situations, it is limited to only acrosswind galloping, which is not always realistic. Recently, there is increasing awareness of the importance of including all three degrees of freedom (3DOF-sway, heave and torsion) for galloping analysis. Therefore, it is necessary to take into account the couplings between the degrees of freedom, especially when the structural natural frequencies are close to each other. A conventional way of conducting stability analysis about the static equilibrium for a 3DOF system is to solve an eigenvalue problem, where the coupling terms can be derived by linearising the change of forces due to the motion. There are two aerodynamic couplings, namely the aerodynamic damping and stiffness. While aerodynamic damping is widely acknowledged to play a pivotal role in galloping, the aerodynamic stiffness has been normally neglected since it is generally considered to be insignificant compared to the structural stiffness, especially for structures with a compact section. However, there seems to be limited research to confirm this impression. Thus, the present work will focus on the significance of the aerodynamic stiffness for a 3DOF system with perfectly tuned and detuned structural natural frequencies. Firstly, a numerical eigenvalue approach will be employed to show the effects of including aerodynamic stiffness along with aerodynamic damping, the results of which will be compared with those of the same 3DOF system but coupled only by aerodynamic damping. Secondly, a case study will be given to stress the necessity of including the aerodynamic stiffness using a full-scale galloping incident reported in the literature.

000022634 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000022634 653__ $$a

000022634 7112_ $$a7th European and African Conference on Wind Engineering$$cLiège, BE$$d2017-07-04 / 2017-07-07$$gEACWE2017
000022634 720__ $$aMacdonald, John$$iHe, Mingzhe
000022634 8560_ $$ffischerc@itam.cas.cz
000022634 8564_ $$s21373$$uhttps://invenio.itam.cas.cz/record/22634/files/197.pdf$$yOriginal version of the author's contribution in proceedings, id 197, section .
000022634 962__ $$r22493
000022634 980__ $$aPAPER