Transverse Resonant Vibration of Non-Bearing Structures Caused by Wind

World Multidisciplinary Civil Engineering-Architecture-Urban Planning Symposium - WMCAUS

土木建筑工程

Jendzelovsky, Norbert^1 ; Antal, Roland^1

STU in Bratislava, Faculty of Civil Engineering, Radlinskeho 11, Bratislava

810 05, Slovakia^1

关键词: Bearing structure;    Building construction;    Potential problems;    Resonant vibrations;    Shedding frequencies;    Transverse resonances;    Vortex shedding frequency;    Worst case scenario;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/245/3/032031/pdf
DOI  :  10.1088/1757-899X/245/3/032031

学科分类：土木及结构工程学

来源: IOP

【 摘 要 】

Nowadays, there are increasing use of very thin, subtle and light structures in the field of building constructions. We can find such a structures as part of roofs or design facades. By using these lamellas like, non-bearing structures as a part of architectural design of buildings, it is necessary to consider wind effects on these structures. Subtle structures of this type are prone to vibration in the transverse direction of the wind flow. The fact that the vibration occurs depends on wind parameters (wind velocity, direction of an air flow) and it also depends on the properties of lamella (shape, length, mass, natural frequency, support type). The principal idea of this article is to show susceptibility of lamellae-like structures to transverse resonant vibration caused by the phenomenon called Von Karman effect. Comparison of susceptibility to transverse resonance vibration was analysed on the different shapes of lamellas loaded by different wind speed. Analysis was based on usage of empirically derived equations. Von Karman effect arise from wind flow past an object. Turbulence in the form of vortices are formed at the object and shed into the flowing stream intermittently. The potential problem is that this turbulence can induce vibrations into the lamella itself. In terms of this vibration problem, two frequencies are interesting. Von Karman shedding frequency is the frequency at which the vortices are formed and shed at the object. The vortex-shedding frequency increases with the velocity of the wind flow and decreases with the size of the object. Natural frequency of the object depends on the construction of the lamella itself. Parameters of lamella as a shape, mass, length, elasticity modulus of material and support types are directly involved in the calculation of natural frequency. Worst case scenario in the term of transverse resonant vibration occurs when the natural frequency of lamella is equal to the vortex-shedding frequency. In this case vibration rises and structure can be snapped or deformed permanently. In the long term vibration, fatigue stress can be significant. At the conclusion hazardous wind speed and recommendations for different shapes and parameters of lamellas are shown.