IDAC Undertakes Indentation and Torque Transmission Analysis for First Subsea Tools

08 November 2012

UK-based provider of engineering analysis Integrated Design and Analysis Consultants (IDAC) undertook Finite Element Analysis (FEA) to determine the degree of indentation in relation to differing pull loads on a Ball and Taper Connector for First Subsea tools.

The study was carried out to ascertain the torque the tool can resist before the indented balls start creating a channel of yielded material.

IDAC undertook the evaluation and research process in two phases - Ball indentation and Torque transmission - within ANSYS, which is a general purpose FEA program.

In the first step, the tool was pre-loaded and pipe was indented, while the indent varied depending on the pre-load.

During the step, which continued for eight different indentation depths, the pocket component was completely fixed on the outside diameter with the pipe component to be pulled so that the ball starts to roll and create an indent on the pipe.

Subsequent to pre-loading and reaching the required indentation, the torque was applied to the tool.

The study found that the pulling force necessary to produce the initial indentation did not display any signs of linear behaviour and followed a 3rd order polynomial curve.

It was also found that pulling forces have a tendency to be constant if indentations were greater than 1.2mm.

The analysis carried out by IDAC for First Subsea on different tools designed by them, provides the design engineers at First Subsea an insight into the performance of new designs.

The study enabled First Subsea to accurately identify the loading capability of 'special' tools that are required to carry out outside normal operating conditions.