| In recent years,the fabricated light wood structure has been developing rapidly in China.With the improvement of people's living standard,more and more people put forward higher requirements for the comfort of buildings besides the safety requirements for buildings.In wooden structure residential buildings,the roof,floor and wall are three major structural systems,in which the wooden floor cover is a system that is in contact with the user's body.In the process of use,the structural system of wooden building covers a significant dynamic vibration response to the external effect.It often brings discomfort to people,affects its environmental quality,reduces work efficiency and life comfort.At present,the quality inspection of the vibration performance of the floor of the wooden building in China is in the initial stage.Only the GB/T51226-2017"multi high rise wood construction technical standard"has mentioned the requirement of the floor vibration performance index,which is urgent to make a breakthrough and development.It is obvious that in order to meet the objective requirements of the safety of the structure of the wooden structure assembly building and the comfort of the user,it is one of the key targets in the wood structure building industry in China to strengthen the testing and analysis of the vibration performance of all kinds of wooden structure buildings.In view of this,based on the research status of the structural vibration of the wooden building cover at home and abroad,the vibration performance test and analysis of the floor structure of a two story light wood structure building are carried out.The main contents include the finite element analysis and calculation,the static load test and analysis of the floor structure,and the modal test of the floor structure.And analysis,vibration test and analysis of floor structure's environmental excitation and impact excitation.In the finite element analysis and calculation,through the field mapping and the dynamic measurement of the elastic modulus of the floor members,the ANSYS software is used to simulate the modal analysis of the floor structure,the concentrated load of the floor structure and the displacement of the uniformly distributed load,and the first order resonance frequency simulation of the building whole mode.Secondly,in the test and analysis of the static load of the floor structure,the test values obtained by measuring the load deflection of the floor structure and the deflection of the concentrated load are compared with the simulated values of the ANSYS software to analyze the coupling of the vibration performance of the floor structure.Thirdly,the modal test of the floor structure is carried out,and the vibration mode of the floor structure system is obtained,and the vibration modes obtained from the finite element simulation analysis are compared and analyzed.Finally,dynamic test and analysis of floor structure's environmental excitation and impact excitation are carried out.The dynamic vibration test of the floor structure is carried out by means of environmental excitation and shock excitation(ball incentive,pedestrian excitation and rhythmic movement).The peak of acceleration and its effective value,its peak value and its effective value and structural damping ratio are analyzed in the dynamic environment.A comparative study.The main conclusions of this paper are as follows:(1)through the simulation and analysis of the ANSYS software,the maximum value of the maximum simulated deflection of the uniform load is 1.47383mm,which is used to calculate the natural frequency of the floor.The calculation value is 17.436Hz,which conforms to the natural frequency standard of the floor,and the uniform load 0.566kN/m is designed according to the floor design.The maximum displacement value of 2 is 2.2659mm,which is in line with FHA standard.The concentrated load of 1kN mainly simulates nine measuring points,the maximum deflection of the nine points is 0.58041mm-1.47383mm,and the maximum deflection value of the middle point in the nine points is 1.47383mm,which is in accordance with the regulations of the Canadian national architecture.The first three natural frequencies are respectively 13.7Hz,13.824Hz and 16.688Hz for the overall analysis of the building.In the modal analysis of building floor,the first three natural frequencies are 16.413Hz,31.847Hz and 48.921Hz.The study of the natural frequency of the building can not be replaced by the study of the natural frequency of the building,and the simulation value of the floor is in accordance with the standard requirements.(2)deflection test is mainly divided into uniform load test and concentrated load test.On the one hand,the uniform load of the floor is simulated by ANSYS software,and the displacement value is 2.2659mm,which is in line with the FHA standard.On the other hand,the floor concentrated load is used to test the displacement deflection values of 9 test points and 6 test lines(x to 3 and y to 3)under 1kN concentrated load.The maximum deflection of the nine test points is0.620mm-1.256mm,and the average error of the simulated value is 13.5%.In the test point,the maximum displacement value is at the middle point of the floor,the value is 1.256mm,the average error is 14.8%,the error of the simulated value is 14.8%,and the six line displacement changes are basically all parabola.Symmetric.(3)the modal test is mainly used to test the vibration performance of the floor structure by one-way and two-way modal test.One way test is x,y,Z three groups,two-way test XZ and YZ two groups.Through the comparison and analysis of the results,the first order natural frequency of the building is 17.25Hz,the first order bending vibration of X,which is in line with China's"combination building".The second order natural frequency is 26.75Hz,which is the second-order bending mode of X direction.The two-way modal test is more stable than the unidirectional modal test.Through the finite element simulation and the theoretical calculation,the estimated frequency is 16.413Hz,17.436Hz,compared with the test value 17.25Hz,the error is small,and the theoretical calculation value is more reasonable and reliable.(4)dynamic test of floor vibration by means of environmental excitation and impact excitation.By comparing the position of six different measuring points,the three natural frequencies of the test buildings are 17.55Hz,26.61Hz and 32.10Hz respectively.The test points are found through the spectrum identification,the data stability and the accurate two conditions.The first order frequency test is relatively stable,when it is in the wall bone column.To avoid vibration nodes,such as 1/4,1/3,1/2 and other nodes,the test results are obvious and accurate.The test excitation is divided into ball excitation(single excitation,multiple excitation),human excitation,and rhythmic motion excitation.The damping ratio of the floor structure is 6%and the damping ratio calculation value is 6%.The maximum value of the peak value of the acceleration is 407.2mm/s~2,the maximum of the peak speed is 5.606mm/s,acceleration under the dynamic condition.The maximum value of the RMS value is 75.3mm/s~2,the maximum value of the speed RMS is0.967mm/s,and the first order frequency is 16.41Hz,which is smaller than the environmental incentive and modal test.The reason is that the quality of the floor can not be ignored,the natural frequency of the floor is affected by the stiffness and quality of the floor,and the value is small.The maximum peak value of acceleration is tested in accordance with the Canadian Standards Committee comfort standard.To sum up,this research provides the basis and reference for the research and development of the assembled light wood structure building in China by testing and analyzing the vibration of the assembly type light wood structure building floor.Engineering value and practical significance. |
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