Research On Mechanical Properties Of Lead Viscoelastic Damper Based On Lever Principle

China is a country with severe earthquake disasters.The deficiency of traditional seismic methods leads to the continuous emergence and improvement of various new damping technologies,of which energy dissipation is one.Efficiency damping technology uses energy dissipation by installing energy dissipators to increase internal damping of structures.Most dampers need large displacement to give full play to their energy dissipation capacity.However,due to the small relative displacement and rotation angle at beam-column joints,the energy dissipation capacity of dampers installed at this position cannot be fully exerted.Therefore,this paper independently developed a lead viscoelastic damper based on Lever.The damper can amplify the small displacement and rotation angle generated by the structure,so that the damper can give full play to the energy dissipation effect.The finite element numerical analysis method is adopted to analyze the damper,analyze its relevant energy dissipation structural parameters,and clearly define the mechanical model applicable to the damper,which mainly includes the following contents:(1)A lead viscoelastic damper based on Lever is proposed.According to the shortcomings of the existing damper,a lead viscoelastic damper based on Lever is proposed.The dimensions of different components in the damper are designed.The structural characteristics,amplification principle,installation and application in engineering and advantages of the lead viscoelastic damper based on Lever are elaborated.(2)Quantitative analysis of the energy dissipation superiority and stress distribution of the lead viscoelastic damper based on Lever by establishing a model without amplification capability shows that the energy dissipation effect of the lead viscoelastic damper based onLever is very obvious,resulting in large shear displacement;And that energy dissipation capability is 9 time that of a damper without amplification capability.(3)The energy dissipation capacity and stress distribution of the damper are studied by establishing a lead viscoelastic damper model based on Lever.The results show that the energy dissipation effect of the lead viscoelastic damper based on Lever is very obvious and the shear displacement is large.The hysteretic curve of the damper presents a parallelogram shape,with large envelope area,strong energy dissipation capacity and full hysteretic curve.The stress distribution of the damper is uniform and reasonable on the whole,and there is no yield failure of the member.The hysteretic curve and skeleton curve obtained by analysis can clearly use bilinear mechanical model to describe the mechanical model of the damper.(4)Through the establishment of 17 damper models with different structural parameters,the influence on the energy dissipation characteristic parameters and energy dissipation capacity of the damper is studied,and the reference is provided for the optimal design of the damper.The results show that with the increase of the number of lead cores,the energy dissipation capacity increases,and the equivalent double lead core arrangement is the best one.The rubber shear modulus of the damper is between 0.4MPa and 0.5MPa,which is the most suitable.The thickness of steel sheet and rubber is more reasonable than that of delta value between 0.5 and 0.6.The stress distribution of the corresponding composite elastomer is more uniform.It is suggested to arrange 4 thin steel plates with a thickness of 2mm in the composite elastomer.