Based On ANSYS Workbench Finite Element Analysis And Optimization Of Shallow Buried Pipe Behind Dam Of Hydropower Station

Based on the numerical simulation method,this paper takes the shallow buried pipe of the Lijiaxia Hydropower Station at the intersection of Jianzha County and Hualong County in Qinghai Province as the research object.By using ANSYS Workbench large-scale finite element analysis software,the shallow burial of the Lijiaxia Hydropower Station is established.Tube 3D solid model and finite element model,static analysis and modal analysis of shallow buried pipe,analysis of stress,strain and vibration characteristics of shallow pipe body.Secondly,combined with the analysis of the stress,strain and vibration characteristics of the pipe body,the steel lining thickness and the steel bar thickness are taken as the design variables,and the optimal equivalent stress,the maximum deformation,the steel lining and the total volume of the steel bar are used as the objective function to establish the optimal design.Mathematical model,the response surface optimization analysis of shallow buried pipe,verify the reliability of the improved design,compare the engineering quantity and cost before and after optimization,and analyze its economics.The main research contents and conclusions of this paper are as follows:(1)This paper introduces the basic concepts of finite element analysis,the unique characteristics of finite element analysis and the specific analysis process of finite element method.It summarizes the introduction,characteristics and basic process of ANSYS Workbench software,and correspondingly in ANSYS Workbench software.The method of selecting materials and the three treatment methods of steel bars in the finite element model of reinforced concrete.(2)Based on the actual situation of the shallow buried pipe behind the dam,three working conditions of the construction period,the normal operation period and the calibration condition were determined.The three-dimensional nonlinear finite element simulation analysis of the pressure pipe body was carried out.According to the analysis of the calculation results-tube stress and strain cloud map,referring to the force of each part of the shallow buried pipe body under different working conditions,it is concluded that the maximum tensile and compressive stress of the shallow buried pipe body is far beyond its The design value has a large surplus,and the pipe body appears in the normal operation period under the unfavorable working condition.(3)The modal analysis of the pressure pipeline under normal operating conditions of the hydropower station shows that the pressure pipe diameter does notproduce severe vibration when the hydropower station is operated under the same unit type and number of starting conditions.The second-order frequency of the pressure pipe is 26.2152 Hz.The natural frequency of the pressure pipeline is 30.239 Hz,and the natural frequency is greater than the second-order frequency.Although the pressure pipeline does not resonate,the two are very close together,so the natural frequency of the pressure pipeline is increased as much as possible in the later optimization design,but also It should be kept away from its third-order natural frequency of 42.516 Hz,preferably around the weighted average of the two,that is,the natural frequency of the pressure pipe is designed to be around 34.000 Hz.(4)Combined with the stress value and vibration characteristics of the pipe body simulated by ANSYS Workbench,the initial structural section of the shallow buried pipe behind the dam is optimized.By comparing and optimizing the engineering quantity and cost of the pressure pipe before and after the design,the optimized shallow pipe can be found.The structure is safe,and it can greatly reduce the engineering quantity and engineering cost,and the economic benefits are very considerable.