BV develops new tools for assessing ice loads

SEPTEMBER 24, 2013 — “All eyes are on the Arctic sea routes and on the opening up of the Arctic mineral and energy resources,” says Pierre Besse, Director of Innovation, Bureau Veritas. “We have to ensure the vessels and offshore units that operate in those extreme conditions are safe. That is why we have invested heavily in research into ice loads on structure and the effects of cargo sloshing caused by collisions with ice for LNG carriers and oil tankers. That investment gives us powerful tools which we are using to shorten the time needed to assess designs for key Arctic projects and routes.”

Image: Nordic Yards

The Paris headquartered classification society has developed new high-level tools to assess cargo sloshing in ice conditions. It has also developed a probabilistic method for assessing ice loads on structure that will reduce the time and data needed to assess the structure of vessels and units designed for heavy ice operation.

A new module for Bureau Veritas’ IceSTAR ice load calculation tool will calculate the kinetic energy imparted to the cargo by a collision with ice. The kinematics derived from IceSTAR can then be used together with CFD analysis to determine how the cargo will slosh and the extra loads this will impose on the ship’s structure and the LNG containment system.

“When gas and oil cargoes begin moving regularly through the Arctic it is certain that ships and ice will interact,” says Mr. Besse. “The energy from those collisions will cause the cargo to move violently, and we have to make sure the ships and especially LNG containment systems are built to withstand that. It is a complex calculation requiring high level modeling but we can do that, and do it in a commercially acceptable time frame. BV is working on a number of high Arctic projects such as Shtokman and Yamal and these tools will make them safe and ready more quickly.”

A research collaboration with the State Maritime Technical University of St Petersburg has led to BV upgrading IceSTAR to include the use of probabilistic methods to calculate ice loads.

“Ice properties vary widely,” explains Mr. Besse. “There are always issues with input data. This research has proven that using stochastic methods we can overcome limitations in the input data to produce safe and robust outputs for the loads which ships and offshore structures may expect from Arctic ice.”