Seismic Performance Evaluation Of Frame Structures With Additional Enlarged Friction Dampers

Earthquake is a sudden natural phenomenon that threatens people’s life and property safety for a long time.In order to deal with earthquake disasters,the commonly used method is energy dissipation and shock absorption,that is,by attaching energy dissipation and shock absorption devices to the structure,and using the energy dissipation device and the structure to resist the earthquake action together to improve the seismic performance of the structure.Friction dampers are widely used in the field of energy dissipation and shock absorption due to their simple structure,low cost and large energy dissipation capacity.However,the commonly used ordinary friction dampers do not consume enough energy under the action of small earthquakes,and it is difficult to achieve the expected earthquake resistance target.In order to better play the role of friction damper and ensure that the structure can effectively dissipate seismic energy under the action of small earthquakes,this paper proposes an Amplified Friction Damper(AFD)device based on the principle of leverage.The input seismic response can give full play to the energy dissipation effect.The main research work is as follows:(1)Expound the research background,purpose and significance of the subject,systematically summarize the current research progress of energy dissipation and shock absorption,the research status of domestic and foreign friction dampers and the research results of amplification mechanism,and finally put forward the research content of this paper.(2)Theoretical analysis of the lever-amplified friction damper AFD device: The components and working principle of the AFD device are described in detail.According to the force characteristics and motion relationship of the device,the restoring force model of the device is established on the basis of related research.Perform hysteretic energy dissipation,displacement,preload and other related parameter analysis.(3)Secondary development and verification of the AFD device of the lever-amplified friction damper: According to the secondary development function provided by ABAQUS,the UEL and VUEL unit subroutines based on the implicit algorithm principle and the explicit algorithm principle are compiled using the FOTRAN language.Comparing the corresponding program in MATLAB with the UEL and VUEL unit subprograms to verify the correctness of the ABAQUS unit subprograms.(4)Analysis of the shock absorption control effect of the steel frame structure: The high-rise steel frame structure model is established by ABAQUS finite element software,and the modal analysis of the structural model is used to verify the rationality of the model establishment.For the structures without control,with ordinary friction damper FD,and with lever amplified friction damper AFD(AFD-2,AFD-3,that is,AFD with magnification of 2 and 3),the seismic and rare earthquakes are respectively fortified.Time-history analysis to compare the dynamic response of the uncontrolled original structure and the shock-absorbing structure.The analysis results show that under the fortified earthquake,compared with the uncontrolled structure,the average shock absorption rate of the maximum interstory displacement angle of the FD model is 20.9%,and the average shock absorption rate of AFD-2 and AFD-3 is 42.5%and 52.1%;Under the earthquake,the average shock absorption rate of the maximum interstory displacement angle of the FD model is about 24%,and the average shock absorption rate of the AFD-2 model and the AFD-3 model is about 39% and 54%.(5)Seismic vulnerability analysis of steel frame structures: Select appropriate ground motion records according to site characteristics,select reasonable seismic strength indicators and structural damage indicators,and divide structural performance levels of different grades according to specifications.The seismic vulnerability analysis based on the IDA method was carried out for the steel frame shock absorbing structure,and the transcendence probability of the structure reaching the ultimate failure state at all levels under different strength PGA was calculated from the perspective of probability statistics,so as to study the seismic performance of each structure.Compared with the FD model,the PGA of the AFD-2 and AFD-3 models reaching the ultimate failure state at all levels increased by 26.6% and 51.1%,respectively,and the large earthquake anti-collapse safety reserve factor CMR increased by about 21.3% and 38.2%,respectively.