Research On Dynamic Characteristics Of Fluid Pressure Differential Pipeline Robot

Differential in-pipe robot is a kind of on-line scanning testing equipment for oil and gas pipelines,as in the east,China and Russia natural gas pipeline,oil pipeline and other projects completed and put into operation,the safety of long distance oil and gas pipelines has become the important factors that affect our economic development and improve people's livelihood,is of great significance for the research of pipeline robot.The pressure differential pipeline robot is self-driven by the fluid pressure difference between the first and the last,which solves the problem of energy supply.At present,numerical simulation is not enough to study differential pressure pipeline robot in China,and the coupling effect between the robot as a multi-flexible body system and the fluid in the pipe is ignored in the model,so it is difficult to accurately predict the dynamic characteristics of pipeline robot in complex pipelines.Based on the actual engineering background,this paper studies the dynamic characteristics of the robot in the process of running with the euler-lagrange(CEL)method.First,this paper introduces the structure principle of the differential in-pipe robot,choice of polyurethane as the design of the cup material,analyzes the hyperelastic Mooney Rivlin,Neo-Hookean and Reduced Polynomial model strain energy function and uniaxial tension nominal stress and the relationship between the draw ratio,through uniaxial tension experiment to determine the Mooney-Rivlin model to describe the material properties of polyurethane.The fracture characteristics of polyurethane under type I crack were studied by numerical simulation and material tensile test,and the correctness of simulation results was verified.Then,the relevant design parameters of pipeline robot are introduced and the specific parameters are defined.In order to verify the correctness of the analytical model,the finite element model of the pipeline robot moving in the pipeline is established,and the stress and strain of the pipeline robot under different working conditions are compared.After the analysis,the output results of MATLAB softwarewere compared with the finite element results,and it was found that the curves of the two calculation methods were consistent under a certain clamping rate,which verified the correctness of the robot dynamic model and the rationality of parameter setting of the finite element model.Pipe welds and l-type pipeline is the main reason,hinder the robot pass around the issue of speed when the robot through the solder joints and the stress change are analyzed,explores under the different solder joint height working environment,one compartment and the stress situation of the compartment,the robot is obtained in the scope of l-shaped pipe size constraints.The universal joint is also an important factor that affects the passage of the robot.Through the numerical simulation of Abaqus software,the motion state and force condition of the universal joint at 8 typical moments are analyzed.Finally,based on CEL method,established the double compartment of fluid-solid coupling model of pipeline robot,this paper expounds the fluid-structure coupling boundary tracking principle,this paper introduces the flow equation of state,and determine the material parameters of the flow of water,the solder joint height of20 mm straight tube and solder joint height is 15 mm,20 mm and 25 mm of l-type pipeline comparison and analysis,explores the pipeline robot cup in the process of exercise stress,the robot speed,the driving pressure and the change law of friction system.