Vertical torsion two-degree-of-freedom segment model wind tunnel test system

Abstract

The invention relates to a vertical torsion two-degree-of-freedom segment model wind tunnel test system. The system comprises two groups of suspension support devices which have the same structure and are symmetrically arranged at two ends, each group of suspension support device comprises a rigid support, a wind attack angle adjusting plate, a support frame, a vertical flutter measurement assembly and a torsion flutter measurement assembly, the rigid support stands on the ground, the wind attack angle adjusting plate is installed on the rigid support, the supporting frame is installed on the wind attack angle adjusting plate through the vertical flutter measurement assembly and can move in the vertical direction, and the torsion flutter measurement assembly is installed on the supporting frame, connected with the segment test model and can conduct torsional motion together with the segment test model. The vertical flutter measurement assembly provides rigidity in the vertical direction of the segment test model through a vertical spring, the torsional flutter measurement assembly provides rigidity in the torsional direction of the segment test model through a transverse spring, and compared with the prior art, the system has the advantages of being high in measurement precision, stable, reliable and the like.

Description

technical field [0001] The invention relates to a bridge segment model test device, in particular to a segment model wind tunnel test system with two degrees of freedom in vertical torsion. Background technique [0002] In the bridge structure model test, the spring suspension segment model test is the most commonly used and the most economical means to study the wind-induced vibration performance of bridges, and it is also an important wind tunnel test device for the identification of bridge flutter derivatives. [0003] For the traditional spring suspension structure, when the initial angle of attack of the segmental model is too large, the spring axis will obviously deviate from the normal direction of the bridge deck, which will cause the stiffness of the model system to change. In addition, due to the limitation of the height of the wind tunnel and the length of the spring, the linear elastic expansion and contraction range of the spring is limited, and the allowable vi...

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Problems solved by technology

In addition, due to the limitation of the height of the wind tunnel and the length of the spring, the linear elastic expansion and contraction range of the spring is limited, and the allowable vibration amplitude of the model is often small

[0004] However, with the continuous increase of the span of modern long-span bridges, especially after the span exceeds 1,000 meters, the deformation of the bridge under the static force of wind load and the torsion angle of the main girder are becoming more and more significant, and the amplitude of wind-induced vibration is also increasing , resulting in the enhancement of the nonlinearity of the aeroelastic effect of long-span bridges

In the segmental model wind tunnel test, when the torsional amplitude is large, if the traditional spring-suspended segmental model is used, the vertical tension spring will have obvious lateral inclination, and the geometric stiffness of the spring will change nonlinearly, especially in the vertical tension. The torsional stiffness provided by the extension spring produces complex nonlinear characteristics with the amplitude, so the vertical and torsional stiffness of the free vibration system with two degrees of freedom in vertical torsion will no longer remain constant, but are related to the amplitude. At the same time, according to previous test experience, The traditional vertical and torsional two-degree-of-freedom coupling free vibration device has a large amplitude and the vertical tension spring will dance or even fall off, making it impossible to simulate the test phenomenon of large torsional amplitude

It will cause unacceptable method errors to the follow-up test results, and its impact on the flutter and eddy vibration performance of long-span bridges cannot be ignored

[0005] In addition, in the actual wind tunnel test, it is necessary to test the vibration of the segmental model under different wind attack angles. Although the initial wind attack angle of the traditional spring-suspended segmental model is adjustable, its adjustable range is small, which weakens the equipment. Ability to implement different test environments

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