| Based on the rotational energy dissipation mechanism,lead and viscoelastic materials are used for collaborative energy dissipation,and a new rotational lead viscoelastic damper is proposed,which has good energy dissipation capacity and does not need to be replaced after an earthquake.The main research results obtained are as follows: The rotational lead viscoelastic damper can be set in the member in the rotating area of the structure.When the rotating deformation occurs,the shear and axial force of the structure are borne and transferred by the pin shaft,and the energy dissipation is reduced by the plastic deformation of lead and the shear hysteretic deformation of the composite viscoelastic layer,so as to improve the seismic performance of the structure.The dynamic recrystallization characteristics of lead and the strong elastic recovery ability of viscoelastic rubber material and the repeatable ability of rotating lead viscoelastic damper can realize the rapid recovery of seismic capacity of structure after earthquake.Pseudo-static repeated tests were carried out on four specimens of rotational lead viscoelastic dampers,and the bending moment-angle hysteresis curves,skeleton curves,strength degradation,cumulative energy dissipation,equivalent viscous damping ratio and the test results under repeated loading were analyzed.The results show that the rotational lead viscoelastic damper has excellent hysteretic properties,fatigue properties and repeatability.The numerical model of the rotational lead viscoelastic damper was established by ABAQUS finite element analysis software.The accuracy of the finite element model was verified by comparing with the experimental results.The yield mechanism,stress distribution and equivalent cumulative plastic strain characteristics were studied to further analyze the energy dissipation mechanism of the damper,and the finite element rotational lead viscoelastic damper models with different design parameters were established for parameter analysis.The results show that: The simulation results of the finite element model of the rotational lead viscoelastic damper are in good agreement with the test results.The stress distribution and energy dissipation are basically concentrated on the lead core.The working mechanism of the rotational lead viscoelastic damper is simple and effective,and the energy dissipation mechanism is clear.The energy dissipation capacity increases with the increase of the thickness ratio of rubber layer to sheet steel and the decrease of the shear modulus of rubber.Combined with the experimental results and finite element analysis,the deformation mode of the rotational lead viscoelastic damper was determined,the restoring force model of the rotational lead viscoelastic damper was derived,and the semi-empirical and semi-theoretical calculation formula of the rotational lead viscoelastic damper was proposed.Combined with a design example,the detailed design flow of the damper was given. |
