Study On Model And Experiment Of Semi-active Control Of Transmission Tower Based On Piezoelectric Friction Damper

Earthquake has been one of the most severe natural disasters, which causes deathsand economic damages. Building structure damage and collapse is the major cause ofhuman injury and death in earthquakes. As a result, seismic engineering is veryimportant in civil engineering. It is a major concern in engineering world to optimizethe structural design with reasonable cost, while maintaining seismic reliability, so thatthe damage to our society in face of earthquakes could be brought to the minimum.Structural vibration control is one of the means to effectively reduce the earthquakedamage. When earthquake comes, the vibration control device can absorb the inputenergy that would otherwise goes to the building structure, reducing the vibrationresponse of the structure. There are three methods of vibration control: structurepassive control, semi-active control and active control. Semi-active control, havingadvantages of the other two methods, is very promising in the future. As the researchon novel materials develops, there are more and more ways to achieve semi-activecontrol. In this paper, a piezoelectric friction damper with Self-back performance basedon inverse piezoelectric effect is proposed. Research in this paper is including:(1) Analyze the constitutive relations and contribute to the mechanism ofpiezoelectric driver, followed by a design of novel piezoelectric friction damper.Propose the damping force model of the damper, at the same time contribute to thetheoretical calculation. Experiment on the piezoelectric friction damper, includingdesign of configurations, measurement of friction coefficient, and test on the drivingcapability. Compare the experimental results with theories, providing a strong supportto the future research of friction damper. (2) Summarize the working principle of semi-active control system, including thesetup of system motion equations, formation of state space, active optimization in LQRalgorithms, and the realization of the optimal Bang-Bang semi-active control strategy.Use FEM-ANSYS to model the transmission tower, to extract mass and stiffnessmatrices. Use MATLAB to create structural damping matrix and control positionmatrix. Through MATLAB coding, achieve optimization in LQR algorithms, and theoptimal Bang-Bang semi-active control strategy. The simulation results show that thefriction damper can effectively resolve the energy and reduce the vibration response ofthe structure. The optimal Bang-Bang semi-active control strategy is also effective, andit lays foundation to vibration table test.(3) Perform vibration table test on a transmission tower with piezoelectric frictiondamper. In the experiment, piezoelectric friction damper is attached to the structurethrough cables, at different heights. The experiment consists of model design,cable-piezoelectric friction damper system design and setup, sensor arrangement,semi-active control system setup, and earthquake input simulation. Perform modalanalysis to the designed system, and record the data for post-experimental analysis,including analysis of damping effect of friction damper and energy dissipation. Thefollowing conclusions are reached: cable-piezoelectric friction damper system caneffectively dissipate energy in an earthquake, thus has a good damping effect; thesmaller the input energy from the earthquake, the better friction damper works; thehigher the cables are setup, the larger displacement between the two ends of thefriction damper, with better damping effect; friction damping system can effectivelyprotect the weak spot of the system. Through comparison between simulation resultswith experimental results, conclusion can be made that the simulation results arereliable. However, simulation results are smaller due to the difference in stiffness andthe way the force is exerted onto the system.