| Submarine pipeline is the most important carrier in the exploitation and transportation of marine oil and gas,however,the working environment of the seabed is extremely complex,causing long-used submarine pipelines to be damaged,and the phenomenon of oil and gas leakage often occurs.At present,the installation process of the existing subsea pipeline connector is more complex and even needs the huge special machine auxiliary operation.Therefore,it is necessary to develop a subsea pipe connector with simple structure,good sealing performance and more convenient installation.This paper proposes a symmetrically structured subsea pipeline connector and its performance is studied.It has important theoretical significance and engineering application value.In this paper,the maintenance technology of submarine pipeline and the technical characteristics of the existing subsea pipeline connector at home and abroad are analyzed synthetically.The structure model of symmetric structure subsea pipeline connector is proposed.According to the technical requirements and design indicators,the overall structure of the connector is determined.This paper designs the key mechanisms of the connector,such as driving mechanism,sealing mechanism,anchoring mechanism,locking mechanism and so on,and the operation process is planned and installed.Based on the statics theory,the mechanical model of the connector anchoring mechanism is established,and the solving formula of the contact stress in the loading process is derived.The relationship between the anchoring performance and the structural parameters of the connector is analyzed,and the multi-abjective optimization mathematical model of the anchoring mechanism is established.The sensitivety and correlation analysis of design variables and objective functions are carried out to get the optimal solution of the main parameters,including the top angle of tooth,the inclination angle of tooth and the inclination angle of the conical surface.The mechanical model for the distribution of the axial force of the pipe and the anchoring teeth is established,and the load taken by the teeth of the force at the end of the force is calculated.According to the variation of the dangerous tooth’s load and tooth number,the optimum range of the tooth number of the anchoring mechanism is determined.Based on the theory of elastoplastic mechanics,the force analysis of the rubber seal ring’s free deformation stage and the constraint deformation stage is carried out,and the contact stress expression of the seal ring is deduced.The stress-strain data of rubber specimens are obtained by uniaxial tensile test.After the ABAQUS software fitting,the material constants of the Yeoh rubber model are determined,and the design basis of the shape and size of the seal ring is proposed.The optimization mathematical model is established by the response surface model method,and the sensitivity analysis of the related variables is carried out.The optimum value of the design variables,such as the thickness of the seal ring,the thickness of the contact surface and the inclination angle of the contact surface,is calculated.Finally,the finite element simulation analysis of the sealing mechanism before and after the optimization is carried out in this paper,and the effect of the optimum design on the sealing performance is proved.According to the designed scheme,the connector test prototype is made.The test on anchor driving force of anchoring mechanism,and the test of ultimate bearing capacity are carried out.the test of the seal performance The results show that the connector has good anchoring and sealing properties.The connector meets the design indicators and validates the feasibility of the design scheme.The symmetrically structured subsea pipeline connector adopts the optimized sealing mechanism and anchoring mechanism,and has good sealing property and load resistance capability,the results have a certain reference for the improvement of the other connector’s performance. |
PDF Full Text Request