A non-contact pneumatic vibration device

Abstract

The invention discloses a non-contact pneumatic excitation device, which is used for pneumatic excitation of flexible structures such as aeroelastic models, and is mainly composed of an air pump, a pipeline, a gas nozzle and a solenoid valve; the air cylinder supplied by the air pump passes through the air circuit The branch is connected with the branch gas circuit; the end of the branch gas circuit is provided with a gas nozzle controlled by a solenoid valve; the solenoid valve and the gas nozzle are integrally arranged, and are supported by a tripod under the aeroelastic model; the solenoid valve and the control unit Electrical connections. The air pump inputs compressed air to the inlet end of the solenoid valve through the branch air path, and the solenoid valve receives the pulse signal from the control unit to realize periodic opening and closing, and outputs pulsed air flow to excite the aeroelastic model. The invention does not contact with the model, eliminates the influence of the additional stiffness and additional mass of the excitation device and the displacement measuring device on the dynamic characteristics of the aeroelastic model, is simple and convenient, and has low cost; it can be used for various flexible aeroelastics such as cable-stayed bridges and suspension bridges Modal testing of the model.

Description

technical field [0001] The invention relates to a non-contact pneumatic vibration excitation device, in particular to a novel vibration excitation device for modal testing of flexible structures such as aeroelastic models of cable-stayed bridges and suspension bridges. Background technique [0002] At present, many long-span suspension bridges or cable-stayed bridges are designed with wind tunnel testing. An important part of wind tunnel testing is the measurement of the modes of a cable-stayed or suspension bridge aeroelastic model. In the traditional method to test the modal, it is necessary to use a hammer or a vibration exciter to contact the model structure, apply a load, and obtain the dynamic characteristics of the model by free vibration or forced vibration. [0003] The aeroelastic models of cable-stayed bridges and suspension bridges are mostly flexible structures with low stiffness. The results obtained by directly acting on the model with an exciter are less ac...

AI Technical Summary

Problems solved by technology

Because when the hammer or the exciter acts, the contact with the model brings greater additional stiffness and additional mass, which changes the dynamic characteristics of the structure, causes errors in the modal test results, and further affects the accuracy of subsequent wind tunnel tests

In addition, traditional excitation methods are mostly single-point excitation, which can only excite low-order modes, and it is difficult to excite high-order modes that are important for wind-induced vibration analysis such as bridge flutter.

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