Verification Test Research For Subsea Unbonded Flexible Pipe Design And Analysis

Pipeline is one of the essentially ways to transport oil and gas in the ocean. Flexible pipe is widely used in the offshore engineering because it possesses of many merits. In general, flexible pipe can be classified into two kinds according to its structural composition, one is bonded flexible pipe, and the other is unbonded flexible pipe. Unbonded flexible pipe is much easier to add layers to add other functions. However, the mechanics behavior of unbonded flexible pipe is difficult to analyze and its exactly constitutive model is hard to build because of the contact and the friction between the layers in the wall of flexible pipes. Therefore mechanics verification tests are obligatory to guarantee the validity of both the analytical and numerical method especially for the new pipe designs. The objective of this paper is to develop a verification test system to validate the design and analysis methodology of a new unbonded flexible pipe made domestically. The necessary of verification tests and the detailed design of every test are explained in this paper. Two kinds of flexible pipe made domestically with different structures are studied based on this testing system. Meanwhile point out the limitation of the theories, and suggest some possible improvements of experiment methodology to develop the theories. This verification test system has set up and assisted many flexible pipes manufacturers to design and validate, including the first domestic flexible pipe which will be used in JZ9-3W in Bohai Bay. Although the system has been established, it needs more sophisticated research to consummate it. The future work will contain two aspects; one is the enrichment of the established validation system, the other will be concentrate on the dynamic experiments such as fatigue test.