Study On Control Performance Of Novel Types Of Track Nonlinear Energy Sinks

Structural control technology is an applied technology that can effectively reduce structural damage,including active control technology,passive control technology,semi-active control technology and hybrid control technology.This paper aims to introduce passive control technology,which has become one of the most common vibration reduction technologies in civil engineering due to its simplicity and economical price.Tuned mass dampers(TMDs)are the most mature passive control technology,which is mainly used in wind and seismic resistance.When the structure vibrates,TMDs can generate resonance at the natural vibration frequency close to the main structure,and rapidly vibrate and consume more energy through the attribute of small mass.However,when the primary structure is damaged or the design of the control device is deviated,TMDs will produce the distuned phenomenon,and the vibration reduction effect of the structural response will degenerate.Nonlinear energy sinks(NESs)are a wide frequency band damping technology,which effectively solves the problem of TMDs narrow frequency band.The track nonlinear energy sinks(track NESs)are a technology to achieve structural vibration reduction through mass' s motion,which generates essential restoring force by adjusting track shape function.The traditional track NESs shape function uses four-order monomial,which has completely nonlinear characteristics.Based on traditional track NESs,this paper proposes new kinds of track NESs – double-terms track nonlinear energy sinks(DT track NESs),vibro-impact track nonlinear energy sinks(VI track NESs)and negative stiffness track nonlinear energy sinks(NS track NESs).In addition,VI track NESs include single-sided vibri-impact track nonlinear energy sinks(SSVI track NESs),single-sided vertical vibro-impact track nonlinear energy sinks(SSVVI track NESs),double-sided track vibro-impact nonlinear energy sinks(DSVI track NESs)and double-sided vibro-impact track nonlinear energy sinks(DSVVI track NESs).NS track NESs include three kinds of NESs without vibro-impact or within vibro-impact(distal-end and near-endvertical vibro-impact)(DEVVI and NEVVI).for this paper,firstly,the motion equations of various vibration reduction technologies are analyzed and derived.Secondly,numerical optimization and simulation are conducted based on the establishment of models.Finally,devices of vibration reduction are verified through experimental study and contrast.1.DT track NESs combine linearity and nonlinearity into one device and are able to solve the issue of weak frequency robustness of linear control devices and weak energy robustness of nonlinear control devices.The equations of motion are constructed.The control parameters of DT track NESs with different polynomial terms are optimized on a three-story steel frame structural model.Investigation shows that the DT track NESs with two-and six-order polynomial terms outperform the DT track NESs with other track shapes.The DT track NESs are compared with tuned mass dampers and track NESs under the impulsive excitation and seismic excitation.The results show that the DT track NESs can effectively reduce structural response under seismic excitation and exhibit high robustness against the change of frequency and input energy.2.VI track NESs are a kind of NESs based on traditional track NESs,with different vibro-impact directions and number of vibro-impact edges as research objects.All kinds vibro-impact track NESs are compared,and the four-order SSVI track NESs are selected as the research objects.Single-sided vibro-impact track NESs(SSVI Track NESs)are configured based on track NESs.With the impacts,SSVI track NESs are of stronger nonlinearity than track NESs and energy in the primary structure can be scattered to higher frequencies where it can be dissipated at a faster rate.Firstly,the SSVI track NESs are theoretically derived and numerically optimized when attached to a three-degree-of-freedom primary structure.Secondly,numerical simulations are carried out on the SSVI track NES system of original structural frequency when subjected to impulsive excitation.Finally,seismic performance of the SSVI track NESs are investigated.The results show that the SSVI track NESs exhibit stronger robustness than tuned mass damper(TMD)against changes of structural frequency and than track NES against changes of input energy.The SSVItrack NESs are overall effective in reducing the structural responses under the earthquakes.3.The vibration absorption performance of traditional track NESs and SSVI track NESs applied to bent high-rise structures is studied.Firstly,the nonlinear restoring force of track NESs and equations of motion for control systems are analytically constructed.Secondly,parameter optimization is carry out when attached to a32-degrees-of-freedom primary structure.The optimized track NESs effectively reduce response and exhibit strong robustness against changes of the device stiffness than the conventional TMD.The track NESs are,however,sensitive to changes of the device damping.To address this issue,single-sided vibro-impact track energy sinks(SSVI track NESs)are proposed.Finally,the control performance of the SSVI track NESs are investigated when changes of device stiffness and damping are considered.The results show the SSVI track NESs are able to effectively mitigate the structural response and exhibit strong robustness against changes of device stiffness and damping in high-rise structures.4.NS track NESs are a kind of vibration absorption device incorporating positive stiffness and negative stiffness,and the displacement generated by movement is small,which are easy to realize.Firstly,theoretical analysis is carried out based on NS track NESs(here is the system equation of motion).Secondly,numerical optimization and performance comparison are carried out,and The NS track NESs which regard the negative equilibrium point as the initial position are determined as the research object.Then,NEVVI-NS track NESs and DEVVI-NS track NESs are proposed based on NS track NESs.Meanwhile,the control performances of NEVVI-NS track NESs,NS Ttrack NESs,traditional track NESs,TMDs and lock system are compared under impulsive excitation and seismic excition.The results show that NEVVI-NS track NESs and NS track NESs can effectively reduce the structural response through negative stiffness effect.In particular,NEVVI-NS track NESs combine the characteristics of negative stiffness and vibro-impact,and both have high energy robustness and frequency robustness.5.The NS track NESs,distal-end vertical vibro-impact NS track NESs and near-end vertical vibro-impact NS track NESs are experimentally studied.Firstly,the experimental design schemes of three types of NS track NESs are carried out.Secondly,the device design and model manufacture are carried out.Finally,experimental results of control systems are compared.