Analysis Of Micro Vibration Response And Control Measures Of Electronic Workshop Under Environmental Excitation

With the rapid development of the domestic electronic industry,large-scale electronic plant projects have higher and higher requirements for micro vibration control.In the project planning and site selection stage,the environmental vibration dominated by road traffic has an important impact on the plant structure selection,scheme layout and even process selection.In extreme cases,it even has too much impact due to environmental vibration,The situation that affects the production after the completion of the project.Therefore,based on the influence of environmental vibration,the research on micro vibration control of electronic plant has important engineering application value.Based on the engineering background of an electronic plant in Jinan,Shandong Province,this paper establishes the overall model of the electronic plant structure by using SAP2000,and studies the vibration response of the electronic plant structure under environmental vibration excitation.The main work of this paper is as follows:(1)Due to the process requirements,the plane scale of the structural unit without joint can reach hundreds of meters.To explore the influence of traveling wave effect of this kind of electronic plant under environmental excitation is the premise to determine the input mode of micro vibration analysis.By comparing the time history response of multipoint input under three kinds of apparent wave velocities with that under uniform input,this paper analyzes the necessity of considering the traveling wave effect of typical electronic factory buildings under environmental excitation.(2)The vibration characteristics of the floor structure located in the cleanest floor of the plant are analyzed based on the excitation time history of the VC / vibration standard,and the vibration characteristics of the floor structure located in the cleanest floor of the plant are evaluated through the analysis of the excitation time history of the project.(3)By comparing the effects of changing the whole floor component parameters and changing the local component parameters of the clean area on the vertical velocity response of the floor,the modeling scheme of structural parameter adjustment is determined;The influence laws of structural parameters such as floor thickness,column section,beam section,concrete strength grade,number of shear walls and length of shear walls on floor fundamental frequency and micro vibration control are discussed,which provides suggestions for the selection and optimization of structural scheme of large electronic workshop.The main conclusions are as follows(1)For typical electronic factory buildings,the influence of traveling wave effect on the vertical velocity response of floor slab is controlled by two factors: apparent wave velocity and floor position.The overall law is as follows: the influence of traveling wave effect increases with the increase of apparent wave velocity;With the rise of the floor,the influence of traveling wave effect is more significant.When the apparent wave velocity is 500 m / s,the floor velocity response considering the traveling wave effect is less than the consistent input;When the apparent wave velocity increases to 1500 m / s,the floor velocity response of the lower floor(first floor of the structure)is roughly the same as that of the consistent input,and the response of some floor nodes of the upper floor(second floor and above of the structure)is greater than that of the consistent input.To sum up,when the clean room of a typical electronic plant is located on the first floor of the structure,it is safe to conduct micro vibration analysis according to consistent input.(2)Under the excitation of vehicle driving environment,the floor speed response increases with the increase of floor,and the area with micro vibration control demand should be set on the low floor if feasible;Based on the 1 / 3 octave analysis,the velocity response of the first floor clean area floor of the background project structure in X direction and Y direction meets the VC-C limit,and the velocity response of some nodes in Z direction exceeds the VC-C requirements,so the anti micro vibration optimization design is required.(3)The anti micro vibration design can be implemented by changing the component parameters in the local area,so as to simplify the model and improve the analysis efficiency.Among the six structural parameters discussed in this paper,the most efficient parameter for controlling the vertical velocity response of the floor is the beam section height.It is preferred to control the vertical velocity response of the floor by increasing the beam height;Increasing slab thickness,increasing the number of shear walls and increasing the length of shear walls have a certain effect on reducing the vertical velocity response of floor slab,but the change rate of velocity response per unit concrete dosage is relatively small,that is,the control efficiency of the above three methods is not high;The methods of increasing concrete strength and column section depend on the frequency of input excitation,which may increase or decrease the speed response.From the perspective of ensuring the control reliability,the above two schemes are not recommended.