Non-contact pneumatic excitation device

Abstract

The invention discloses a non-contact pneumatic excitation device which is used for pneumatic excitation on flexible structures such as an aeroelastic model and the like. The non-contact pneumatic excitation device mainly comprises an air pump, pipelines, air nozzles and electromagnetic valves, wherein an air cylindersupplied with air by the air pump is connected with branch air pipelines through an air pipeline brancher; the air nozzles controlled by the electromagnetic valves are arranged at the end parts of the branch air pipelines; the electromagnetic valves and the air nozzles are integrally arranged and supported below the aeroelastic model by tripods; the electromagnetic valves are electrically connected with a control unit; the air pump inputs compressed air into air inlet ends of the electromagnetic valves through the branch air pipelines, and the electromagnetic valves receive pulse signals sent by a control unit to realize periodic opening and closing and output pulse airflow for excitation on the aeroelastic model. The device is not contacted with a model, influence of additional rigidity and additional quality of an excitation device and a displacement measurement device on dynamic characteristics of the aeroelastic model is eliminated, and the device is simple, convenient and low in cost; the non-contact pneumatic excitation device can be used for modal testing on various flexible aeroelastic models of a cable-stayed bridge, a suspension bridge and the like.

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 cable-stayed bridges and suspension bridge aeroelastic models. Background technique [0002] At present, many long-span suspension bridges or cable-stayed bridges are designed with wind tunnel tests. An important part of wind tunnel testing is to measure the modes of aeroelastic models of cable-stayed or suspension bridges. In the traditional method of testing the mode, it is necessary to use a hammer or an exciter to contact the model structure, apply a load, and use free vibration or forced vibration to obtain the dynamic characteristics of the model. [0003] The aeroelastic models of cable-stayed bridges and suspension bridges are mostly flexible structures with low stiffness. The accuracy of the test results obtained by directly acting on the model with the vibrator is...

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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