Mechanical Performance Of A Novel Arc-surfaced Frictional Damper And Its Application In Container Crane For Vibration Control

Frictional energy dissipation technology is a very important part of structural vibration control and has been developed rapidly in engineering application.Frictional damper is one type of such devices which dissipates the energy through frictional sliding between two solid bodies.However,in most traditional frictional dampers,the frictional force is pre-determined as constant value once the configuration and materials are selected by designers,and its frictional force and initial sliding force are also determined.Due to the uncertainty of seismic load,the conventional friction damper cannot be controlled to adapt to this situation.For this purpose,a novel arc-surfaced frictional damper(AFD)is proposed.The major advantages of AFD,with improved adaptive ability and energy dissipation ability,are that its frictional surfaces are curved so that the damping force varies with displacement.A series of research on mechanical model,performance tests and its application in container crane for vibration control are conducted by combination of theretical analysis,test and numerical simulation.The main works are listed as follows:(1)A novel arc-surfaced frictional damper with variable damping force and great energy dissipation capacity is developed.The structural preporties and working principle of arc-surfaced frictional damper are introduced,and its formula is given.MATLAB was used to simulate the mechanical performance of this damper,and compared with the conventional friction damper,the energy dissipation capacity is greater.(2)Experimental tests on mechanical properties of AFD were carried out.After cyclic loading,the hysteretic characteristics of the damper such as saddle-shaped curve with stable hysteresis loops,stable damping and stiffniss,great energy dissipation capacity under the same displacement,are obtained.It is verified that the theoretical results agree well with the experimental results and the proposed mathematical model can be used to predict the hysteretic behavior of AFD.It can be used to design the damper.(3)Application of AFD in container crane for vibration control is conducted.The proposed damper is applied in container crane for vibration control based on a seesaw mechanism and a diagonal brace device.A simplifed trilinear force-displacement model on the basis of experimental results is adopted to represent the hysteretic behavior of AFD.A method based on the displacement and energy dissipation ratio is proposed to find the optimum slip force for seesaw damping system.Analysis on the damping effect of AFD control system is conducted.Simulation results prove a feasible application of AFD control system to absorb large amounts of seismic energy and significantly reduce the structural responses,especially for seesaw damping system.The displacement is reduced by up to 61%.