Development And Test Study On Double-body Connector Of Submarine Pipeline

Submarine pipeline is an important carrier of offshore oil and gas resources transportation to land. Once the leak occurs, not only will it destroy the marine environment, but also it causes huge economic losses. Therefore, submarine pipeline repair technology is attracting more and more attention. In this paper, the author makes a detailed study and design of a double-body 2-inch submarine pipeline connector, which can achieve rapid repairing of damaged pipeline without divers' operating and then conducts a prototype testing.Basing on synthetic analysis of various existing submarine pipeline repair technologies with focusing on mechanical connector repair technology, the author introduces repair process,required equipment, use limitations of the technologies, and divides the connector into four mechanisms for detailed study. After comparison and analysis of different forms of the mechanisms,the author determined the connector's partial,overall structure, and the installation process.For anchoring mechanism, firstly, the author studies the driving force: solves the desired radial pressure when embeds single anchoring tooth into pipe, and determines the number of anchoring teeth being embedded into pipe simultaneously. Then the maximum driving force of anchoring mechanism with different numbers of anchoring teeth is obtained; The calculation results are verified by experiments. Secondly, the author studies the carrying capacity:establishes a mechanical model of the axial force distribution in pipe anchoring section, in which obtains load distribution among different anchoring teeth; Theoretical model is verified by finite element simulation; The model is applied to determine the optimal number of anchoring teeth, and calculate the required driving force. Ultimate bearing capacity is obtained by tests, and the force distribution is verified.For sealing mechanism, its deformation under load process is divided into two stages. The author carries out mechanical analysis for each stage separately and establishes mechanical model of the driving force and contact stress between the sealing surfaces. Conducts parametric analyses of sealing mechanism, it also studies the effect of sealing mechanism parameters on properties of sealing mechanism. Moreover, the author Comprehensively considers driving force, the sealing performance and control difficulty of compression volume, determines the optimum parameters of sealing mechanism, carries out finite element analysis to analyze driving process, obtains the compression distance, and provides design basis for the driving mechanism and the locking mechanism.Finally, according to the driving force of the anchoring mechanism and sealing mechanism,the paper determines the size of the driving mechanism and the locking mechanism and processes experimental prototype. Through the functional test, it verifies the feasibility of the connector structure scheme and meets the design specifications. Comparing the test of different sealing mechanism by prototypes,the paper obtains driving force and sealing ability of different forms of sealing mechanism.