拉索风雨激振机理及减振措施的研究

THE ANALYSIS OF THE MECHANISM OF RAIN-WIND-INDUCED VIBRATION AND DISPLACEMENT-RESTRICTION DEVICE

该文在已有理论的基础上,提出了一种新的拉索风雨激振的理论解释,并针对拉索的风雨激振提出了一种新型的减振装置——限位装置。运用解析法和数值法模拟了拉索的风雨激振现象,所得结果与以往研究者得到的解析结果及试验现象相一致。在此基础上,运用有限元方法模拟了限位装置,研究了其对拉索风雨激振的抑制作用。从能量原理和致振机理两个角度,阐明了限位装置的减振机理。讨论了间隙和限位位置对减振效果的影响。结果表明:斜拉索发生风雨激振时,可以将风雨对拉索的作用简化为上水线绕拉索周向振动时,作用在拉索上的离心力,以此解释风雨激振的机理;限位装置能显著减小拉索风雨激振的振幅;限位装置减振机理明确,能够从根本上抑制风雨激振的发生;减小间隙或将限位位置向拉索中间靠拢,会使减振效果更加明显。

Based on available analytical and experimental results,a new explanation for the mechanism of the rain-wind-induced vibration was introduced.Meanwhile,a device designed to restrain the larger displacement of a stayed-cable was proposed to mitigate the rain-wind-induced vibration.Analytical and numerical methods were used to simulate the phenomena of the rain-wind-induced and the results were in good accordance with available analytical or experimental ones.Further,the influences of the gap and the location of the device,which may affect the efficiency of the device,were studied.It concluded that the mechanism of the rain-wind-induced vibration could be explained as the action of the centrifugal force of the water around the circumference of the cable＇s surface.And the effectiveness of displacement-restriction device on mitigating large-amplitude vibration could be explained by both the theory of energy and the mechanism of rain-wind-induced vibration.With regard to the efficiency of the device,it was found that the smaller the gap between the device and the cable,and the further the location of the device from the end of the cable;that the more significant effect could be achieved to mitigate the vibration of the cable.