Flow Control By Bionic Travelling Wave Wall Of Wind-induced Vibration

With the increasing of bridge span, the bridge structure becomes softer, and thedamping of the bridge structure becomes smaller. the bridge is more prone to vibrationunder the dynamic loads, so bridges become more sensitive to wind, long-span bridgestructure under the effect of the wind can happen wind-induced vibration easily. Thewind-induced vibration to become one of the controlling factors of long-span bridgedesign cannot be ignored, therefore, to carry out the flow control of wind-inducedvibration is of great significance. This paper use a new-style active flow controlmethods-flow control by bionic traveling wave wall, making a flexible traveling wavewall on the surface of the structure, can cause the suppression of the boundary layerflow separation, and finally cause the suppression of the wind-induced vibration ofstructure. This paper use smart materials/MEMS (Micro-Electro-Mechanical Systems)technology to integrate the bionic travelling wave wall system. First, selecting twokinds of smart material actuators, one is piezoelectric ceramic actuator, another is IPMC(Ionic Polymer Metal Composite) actuator. Wind tunnel tests for flow control of thebionic travelling wave wall system integrated by the piezoelectric ceramic actuator havebeen done to study the effect of this system. The main contents of this article include:First, selecting the THUNDER (THin UNimorph DrivER) piezoelectric ceramicactuator, testing the relationship between drive voltage and the dynamic displacement,calculating theoretically the dynamic displacement of the THUNDER actuator by theconstitutive relation of piezoelectric ceramic, the calculation results with theexperimental results for comparative analysis.Secondly, integrating the bionic travelling wave wall system with a number ofTHUNDER actuators, analyzing the parameters controlling factors of the travelingwave wall system, and studying the wind tunnel tests of the traveling wave wall systemon the suppression effect of boundary layer flow separation, the results show that thebionic travelling wave wall system for flow control has a certain effect.Then, Through some preparation process, preparing a flexible smart materialsactuator: ionic polymer metal composite actuator, with platinum Pt and silver Ag as theelectrode of the IPMC.Finally, testing the dynamic displacement of prepared IPMC actuator, the resultsshow that the dynamic displacement amplitude of the IPMC actuator is10times largerthan the one of the THUNDER actuator, and its desired voltage amplitude is also muchlower than the THUNDER actuator. At last using multiple IPMC actuators to integratethe bionic travelling wave wall system.