Optimal Design Of Passive Dampers Based On Pole Assignment

The passive damper has been widely used in the field of structural vibration controlbecause of high reliability, simple installation, easy maintenance and low cost. However,there is still no practical method for design of various passive dampers according todamping characteristics. Therefore, the research about optimal design of passivedampers is particularly important. This paper studies the optimal design of passivedampers based on the pole assignment method. The main content is as follows.The placement of poles and the pole assignment mehod are studied. Based on theenergy, the influence of LQR control on poles of the system with the weight matrixchanging is analyzed. Thus it provides a reference for the placement of poles. And thespecific recommendation is given for the placement of poles including damping ratio,frequency and the number of pairs through the numerical simulation. After analyzingthe limitation of commonly used pole assignment methods, the pole assignment methodbased on decoupled real modal is proposed in this paper. The feedback gain matrixobtained by the given pole assignment method matches the characteristics of varioustypes of dampers. And it is better to be applied in the optimal design of passivedampers.Optimal design for parameters of passive dampers is studied. After comparing thedirect solving method, the equivalent optimal control method and the least squaresmethod, the equivalent optimal control method is applied in optimal design forparameters of viscous dampers, viscoelastic dampers and metal dampers in the firststage. The method based on the equivalent dissipated energy that was used in optimaldesign for parameters of metal dampers in the second stage was proposed. The results ofsimulation show that this method is feasible and effective, so that it makes optimladesign for parameters of metal dampers based on pole assignment possible.Optimal design for location of passive dampers is studied. The method based onthe damper’s dissipated energy was proposed. The damper whose dissipated energy isthe least is gradually removed or replaced for viscous dampers and metal dampers. Andit is necessary for the viscoelastic damper to revise the optimal design for locationaccording to the story drift due to ignore of its stiffness.The process of optimal design for viscous dampers, viscoelastic dampers and metal dampers is conducted. The numerical simulation of a20-story steel frame structureinstalled with passive dampers is used to verify the reach of the expected control effect.It proves that the process of design is effective and rational.