Pre-compression rings
An iron fist - in reverse
10 Sep 2018
Knowing that the large electromagnetic forces at work during machine operation would cause stress over time to °ÄÃÅÁùºÏ²Ê¸ßÊÖ's largest magnet set, engineers devised a compression system to "push back." The resilience of the solution—large composite "pre-compression" rings that will encircle the tips of the toroidal field coil cases at top and bottom—is about to be tested at a dedicated facility.Â
This unusual test bench has 36 actuators exerting a force of 1,000 tonnes each. They will operate simultaneously to subject the toroidal field coil magnet system's pre-compression rings to °ÄÃÅÁùºÏ²Ê¸ßÊÖ-like forces in order to test their resistance and durability.
At a brand-new facility at CNIM (La Seyne-sur-Mer, France) everything is ready for the arrival of an exceptional test bench, capable of applying stresses similar to those of °ÄÃÅÁùºÏ²Ê¸ßÊÖ operation to the toroidal field coil pre-compression rings and measuring millimetric deformation.
The tool, developed by Douce Hydro (France) in collaboration with CNIM, will subject the rings to a combined circumferential force of 36,000 tonnes while maintaining a positional accuracy of 0.1 mm. The test on each ring will last a few hours and will be supplemented by other tests to confirm creep and fatigue performance.
The °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization is procuring the test facility and tooling through a contract awarded to the CNIM/Douce Hydro consortium, while the European Domestic Agency has developed the conceptual design of the test facility and is responsible for technical progress.
Neil Mitchell, °ÄÃÅÁùºÏ²Ê¸ßÊÖ Magnet Division head, cites the collaboration as "an excellent example of °ÄÃÅÁùºÏ²Ê¸ßÊÖ Organization and the European Domestic Agency working as a single team to construct the facility within budget and to schedule."
At a newly created facility at CNIM, representatives of °ÄÃÅÁùºÏ²Ê¸ßÊÖ, the European Domestic Agency, manufacturer Douce Hydro and host CNIM stand before the test bench where nine pre-compression rings will be tested (three upper, three lower and three spare).
The European Domestic Agency is responsible for the fabrication of nine pre-compression rings (three top, three bottom and three spare). Weighing roughly 3 tonnes each, with an inner diameter of 5 metres, they are made of a fiberglass composite that consists of more than one billion minuscule glass fibres glued together using epoxy resin. This material—the result of an in-depth R&D program—has proved to be the best material for withstanding high loads and avoiding the circulation of current.
The first full-scale prototype should be delivered to the test facility by the European Domestic Agency before the end of the year. Eventually all nine of the pre-compression rings will be proof tested before installation.
Read the original report on the European Domestic Agency .
The first full-scale prototype should be delivered to the test facility by the European Domestic Agency before the end of the year. Eventually all nine of the pre-compression rings will be proof tested before installation.
Read the original report on the European Domestic Agency .