Study On Dynamic Characteristics Test And Deformation Analysis Of Ying County Wooden Pagoda

Yingxian Muta was built in 1056 AD,has a history of more than 900 years.It is one of the most brilliant masterpieces of Liao Dynasty architecture,and is also the highest existing wooden structure in the world.Its excellent construction technology is worth learning and studying.Due to the age,the Yingxian wooden tower is now damaged and deformed,and it needs to be repaired and reinforced.This paper mainly analyzes the dynamic characteristics of the county wooden tower in response to the in-situ dynamic test of Yingxian wooden tower,and combines the large-scale finite element software ANSYS to establish the overall model of Yingxian wooden tower,and analyzes its modal parameters and static load.Deformation and internal forces.At the same time,through the investigation of the deformation of the wooden tower,the inclination and torsion status of the columns of the wooden tower are analyzed,and the inter-layer displacement angle values of the current layers of the wooden tower are calculated,and the damage status of the wooden tower is made based on this.A preliminary assessment.Through the in-situ dynamic characteristics test of the corresponding county wooden tower,the pulsation signals of the stigma and column roots of the various layers of the Yingxian wooden tower under the environmental pulse action were collected.Through the time-domain analysis of the peak acceleration response of the column heads in the various columns of the wooden tower,the distribution of the acceleration response of the column heads in each layer of the wooden tower is obtained.The results show that the acceleration response of the column root is generally higher than the peak response of the column head,and the peak response of the outer groove column is greater than the peak value of the acceleration response of the inner channel column.The natural vibration frequency,damping ratio and vibration mode of the wooden tower in the east-west direction and the north-south direction are studied by the combination of the peak picking method and the random subspace method.The seventh-order translational and torsional modal parameters of the wooden tower are obtained.Using the large-scale finite element analysis software ANSYS,the finite element analysis model of the residual deformation of Yingxian wooden tower was established.The spring element was used to simulate the semi-rigid characteristics of the bucket and beam-column joints,and the modal parameters were analyzed.The simulation results and experiments were carried out.The test results are more consistent.The results show that the first-order translational frequency of the wooden tower is 0.601 Hz(north-south direction),the second-order translational frequency is 0.635 Hz(east-west direction),the third-order translational frequency is 1.660 Hz(north-south direction),and the fourth-order translational frequency is 1.671Hz(east-west direction),the fifth-order translational frequency is 2.735Hz(north-south direction),and the sixth-order translational frequency is 2.778Hz(east-west direction).The first order twist frequency is 0.927 Hz.The first and second order damping ratios are 3.29%,the third and fourth order damping ratios are 2.08%,and the fifth and sixth order damping ratios are 1.99%.The first-order damping ratio was reversed to be 2.41%.Through the Ying County wooden tower deformation measurement test,the tilt and torsional deformation of each layer of the wooden tower were studied and analyzed.The results show that the second and third layers of the wooden tower have the largest inclination,the maximum inclination of the second layer is 583 mm,the maximum inclination of the square column is 578 mm,and the whole of the second layer is inclined to the north.The maximum tilt value of the three-layer cylinder is 803 mm,and the maximum tilt value of the square column is 603 mm.The three layers of the entire layer are inclined to the southeast direction,and the flat layer is inclined to the southwest.The torsional deformation of the second layer reaches a maximum of 581 mm,and the torsional tendency of the outer groove and the inner groove of the other layers is polarized.The ANSYS was used to simulate the wind load and the self-weight load of the wooden tower,and the static deformation and internal force of the wooden tower were analyzed.Based on the tilt deformation of each column of Yingxian wooden tower,based on the displacement angle between layers,the damage status of each layer of the wooden tower was evaluated.The results show that the damage of the two-layer bright layer,the threelayer flat layer and the three-layer clear layer is the most serious.