Seismic Response Analysis Of Buried Water Supply Pipeline Baesd On Fluid-Solid Interaction Theory

As the main artery of the city,the buried water supply pipeline is related to every aspect of the city’s daily production and life,and the importance of ensuring its safe operation is self-evident.China is a country with frequent earthquakes.Once the city suffers earthquake damage,the buried water supply pipeline is prone to deformation or even damage under the influence of the earthquake,resulting in secondary disasters in the earthquake area.In the past,the research on seismic model of buried pipeline mainly focused on the interaction between pipe and soil,but ignored the influence of the interaction between fluid and pipeline on the seismic performance of pipeline.In view of this,based on the fluid-solid interaction theory,this paper establishes the fluid-solid interaction model of buried water supply pipeline,analyzes the seismic response of the model,and the main research works are as follows:(1)Firstly,through the induction and analysis of the static model and the dynamic model of the buried pipeline under the seismic action,combined with the theory of fluid-solid interaction,based on the quasi-static method and the seismic wave theory,the mathematical calculation model of the axial stress,the transverse stress and the combined stress of the buried water supply pipeline under the seismic action without considering the fluid-solid interaction is derived.Based on this model,combined with the fluid-solid interaction vibration equation,the simplified additional mass method is used to deduce the fluid-solid interaction displacement response equation related to the natural vibration frequency of the water supply pipeline,and the basic control equation of the fluid-solid interaction finite element of the water supply pipeline is derived by using the variational principle.(2)Secondly,according to the fluid-solid interaction finite element theory,the fluid-solid interaction model of buried water supply pipeline under earthquake is established by using ANSYS Workbench software,and the tetrahedron element is used instead of hexahedron element to generate the fluid area grid in the pipeline.The post-processing results of the model show that when the local seismic acceleration reaches the peak value,the total deformation and stress of the pipeline reach the maximum value:the maximum value of the total deformation is 1.1251 mm,which is located in the middle of the pipeline;the maximum value of the equivalent stress is 45.45 MPa,the maximum value of the axial stress is 67.652 MPa,and the maximum value of the transverse stress is22.128 MPa,which are located at the outlet of the pipeline..(3)Finally,the comparison results of the maximum stress of water supply pipeline without water,water supply pipeline without considering fluid-solid interaction and water supply pipeline model with fluid-solid interaction are analyzed by examples.Based on the model,the equivalent stress response of water supply pipeline under different parameters such as velocity,working pressure,buried depth,pipe diameter and wall thickness is explored.The results show that the existence of water will make the pipeline When the equivalent stress increases 1.97 times,the equivalent stress of the water supply pipeline will be reduced by 154% due to the fluid structure coupling effect.The equivalent stress of the pipeline increases with the increase of the buried depth,wall thickness and working pressure of the pipeline.It is not affected by the flow velocity of the fluid in the pipeline.It first increases and then decreases with the increase of the pipe diameter.Under the same conditions,the equivalent stress of the DN800 pipeline is the minimum,the minimum value is 34.711 MPa,and the seismic performance is the best.