Theoretical And Experimental Study On Vibration Reduction Of High-rise By Composite Damping Cable

The high-rise structures are prone to large-scale vibration under the strong wind due to the their high flexibility and low damping.It also endangers the safety of the structure.The existing vibration-damping technology is difficult to meet the vibration-reduction requirements of multi-mode and ultra-low-frequency vibration of high-rise structures.Model test studies have proved that the composite damping cable has good damping effect.In this paper,the damping mechanism of the composite damping cable and the tower-type structure is studied,and the accuracy of the analytical formula is verified by experiments.1.A damping model of the discrete system of the tower-type structure is established.The composite damping cable is suspended at the top of the structural column.Firstly,the differential equation of the system is derived and the general solution of the characteristic equation is solved by the Shengjin formula.Then the analytical expression of the damping ratio is obtained,which is a quantitative index of the effect of the composite damping cable on the vibration reduction of the tower-type structures.The experiments have verifies the accuracy of the analytical solution under the discrete system.2.The parameter analysis of the damping ratio of the discrete system is analyzed.The single-parameter and double-parameter accurate calculation and the trend research are carried out.With the stiffness of the reset spring is increased,the additional damping ratio of the structure is decreased.The additional damping ratio of the structure increases with the increase of damping coefficient.And with the diameter of the main cable is increased,the additional damping ratio is increased slowly.Moreover,while the inclination of the main cable increases from 0° to 90°,the additional damping ratio increases to the maximum and then decreases,which provides a theoretical basis for the optimal design of the structure.3.Based on the composite damper cable of the high-rise structure discrete system,the vibration reduction model with continuous system of the high-rise tower-type structure with composite damping cable is established.The composite damper cable is hung to any position of the structural column.The differential equation of the system motion is established through the Lagrangian equation.The eigenvalue equation and the analytical solution of damping ratio are solved by Shengjin formula.When the composite damper cable is suspended at the top of the tower,the damping ratio between the continuous system and the discrete system is compared,and the relative error is within 2.2%.By comparing and analyzing two different first-order modes of the high-rise tower-type structure,the relative error of damping ratio is within 1.0%.Finally,by changing the damping coefficient,the ground dip angle and the position of suspension point of the composite damper cable and the towering tower structure,the analytic solution of the damping ratio and the fitting performance of the experimental damping ratio of the tower structure continuous system are proved to be better.The relative error is small and the analytical solution is accurate.It provides a theoretical basis for further optimization of the structure.