Triangular Tension Leg Platform Motion Performance Research

Tension Leg Platform has been used widely in the deep water oil and gas developmentfield with its excellent motion performance. Because its work site is far away the seacoast theprobability of encountering severe sea condition for the Tension Leg Platform increase greatlyand its safety is faced with severe challenges, so the hydrodynamic performance of theTension Leg Platform has become the focus of the study of the International MarineEngineering. In this paper, the frequency domain and the coupled time domain method arecombined to study the hydrodynamic performance of the Tension Leg Platform, as follows:Firstly, derive the heave force and tendon tension formula of the four-column ExtendedTension Leg Platform based on the long-wave assumption to research the mechanicalcharacteristics of Tension Leg Platform. Then create parametric model and parametricoptimization process of the Extended Tension Leg Platform, use the minimum tendon tensionas the objective function to optimize the main dimensions of the platform, and to verify theeffectiveness of the optimization process.Next, derive the heave force and surge force formulaof the triangular Tension Leg Platform refer to the force formula of the Extended Tension LegPlatform to study the mechanical characteristics of the triangular Tension Leg Platform.Secondly, use the frequency domain method to analysis the hydrodynamic performanceof the triangular Tension Leg Platform to get its hydrodynamic coefficients of six degrees offreedom, first-order wave force and second-order wave force. Then evaluate the motionperformance of the platform based on the response amplitude operator (RAO).Finally, use the coupled time domain theory to study the motion response of thetriangular Tension Leg Platform and the tendon tension variation under two different tendonlayouts. The results show that changing the number and properties of the tendon has slighteffect on the platform’s motion response of surge, sway and heave, but can significantlyreduce the tension of each tendon with the pre-tension of the platform remains unchanged. Italso notes that the effect of wave-frequency force on tendon tension is much larger than thatof low-frequency force.