Abstract
In order to study the influence of rainfall on the critical wind speed of flutter of long-span suspension bridges in mountainous area, the impact of rainfall on stiffening girder is analyzed based on the main characteristics of rainfall and the movement speed in all directions. The mechanical equation under the joint action of wind and rain is established and the impact force is transferred, the damping effect of rainfall is then derived, and the element damping matrix form of rainfall is obtained by combining the integration of shape function. Furthermore, the flutter motion equation of wind-rain-bridge coupling system is derived, and the finite element analysis method for critical wind speed of structural flutter considering the influence of rainfall is established. Finally, taking a large-span suspension bridge in mountainous area as the research object, the influence of rainfall on the critical wind speed of flutter is analyzed, the results indicate that the critical wind speed of flutter will be accordingly increased due to the existence of rainfall damping, whereas the mass of raindrops is too light and the final velocity of raindrops in the falling process is low, the critical wind speed of flutter increased by only 5.54% in the case of heavy rainstorm. Therefore, when the rainfall intensity is general, the influence of rainfall on the critical wind speed of flutter can be ignored.
Highlights
In order to study the influence of rainfall on the critical wind speed of flutter of long-span suspension bridges in mountainous area, the impact of rainfall on stiffening girder is analyzed based on the main characteristics of rainfall and the movement speed in all directions
The flutter phenomenon of long-span bridges has been studied by researchers at domestic and foreign[4], there are few studies on the effect of rainfall on the critical wind speed of flutter
Wang Liang[6] found that the aerodynamic derivatives were greatly affected by rainfall, and the critical wind speed of flutter at the positive attack angle was smaller than that at the negative attack angle based on the study on the stability of flutter induced by wind and rain of long-span bridges
Summary
And it is assumed that the motion speed of cross section is far less than that of raindrops, and moves along the Y axis and Z axis in Fig. respectively and torsional movement is carried out at speed θx,the. Y 2 、 Z 2 and θ x are ignored,when rainfall impact load of cross section can be obtained by its square values integrating the surface load of rainfall, as shown in Formula (2) is expanded, the impact of rainfall is further. ; rainfall damping is considered in flutter analysis. N of spatial beam element and the principle of virtual work, the unit into the impact force P and damping of rainfall C, namely: damping matrix of rainfall can be expressed as:. And the result after integration is shown in Formula (4). . The impact of rainfall only has a static displacement effect on the structures, and
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