A Large-Diameter Threaded Connector for Tension Leg Platform Tendons

Abstract

This paper discusses the development of a large diameter threaded connector for tension leg platform (TLP) tendons. The connector is designed to join sections of 48 inch (1.22 meter) outside diameter, 1. 625 inch (0.041 meter) wall thickness pipe that make up the TLP tendons. This work is part of a broader research effort aimed at demonstrating the use of large diameter tendons. Use of large diameter, buoyant tendons results in TLP designs that are relatively insensitive to water depth.Elastic and plastic finite element analyses were conducted on various axially and radially preloaded connector concepts to study ways to reduce stress concentration factors (SCFs), improve static strength and resistance to jump-out, and evaluate sensitivity to machining errors.The results favored a radially preloaded connector concept. The resulting design has a weight of only 2.4 times the corresponding unit weight of the tendon pipe, a low SCF (less than 1.4), and a static strength greater than the tendon pipe. It also can be machined using conventional, computer controlled machines.A comprehensive testing program aimed at verifying the structural and functional performance of the connector was carried out.

Fatigue-Life Predictions for Threaded TLP Tether Connector

“…The life prediction technique presented in this paper was used to confirm the pin/box type assembly of our conceptual tether design [2] is more fatigue resistant than the pipe. This TLP threaded connector is designed to connect sections of the 48-inch O.D.…”