| Paper |
Title |
Page |
| WEPKF037 |
Structural Analysis of an Integrated Model of Short Straight Section, Service Module, Jumper Connection and Magnet Interconnects for the Large Hadron Collider
|
1684 |
| |
- S. Dutta, J. Dwivedi, A. Kumar, H.C. Soni
CAT, Indore (M.P.)
- B. Skoczen
CERN, Geneva
|
|
| |
The Short Straight Section (SSS) of the Large Hadron Collider (LHC) houses a twin quadrupole.The cryogens are fed to the SSS through a Jumper Connection between service modules of Cryogenic Distribution Line (QRL) and SSS.A Finite Element analysis has been performed in collaboration with CERN for the unified model of SSS of LHC,consisting of cold mass, cold supports,vacuum vessel and its bellows, interconnects, jumper connection and alignment jacks. The model has been developed to understand coupling between the quadrupole magnet and the service module due to ground motion and during the realignment or global smoothening of the LHC arc. The model incorporates experimental stiffness values for support posts, internal pipes and jacks and calculated stiffness for magnet-to-magnet interconnects. The computation space and time has been reduced by executing a two step linear static analycal approach with an initial trial analytical approach cycle in which the program estimates the behavior of the flexibles. A special routine is developed within ANSYS,using APDL which selects the correct secant stiffness of flexibles(by applying a user interactive logical algorithm)from their non-linear force displacement characteristics.
|
|
| WEPKF038 |
The Alignment Jacks of the LHC Cryomagnets
|
1687 |
| |
- J. Dwivedi, S.G. Goswami, A. Kumar, V. Madhumurthy, H.C. Soni
CAT, Indore (M.P.)
- V. Parma
CERN, Geneva
|
|
| |
The precise alignment of the some 1700 cryomagnets of the LHC collider, requires the use of some 7000 jacks. The specific requirements and the need for an cost-effective solution for this large production, justified the development and industrialisation of a dedicated mechanical jack which was developed, and is now being produced, in the framework of a collaboration between CERN and the Center for Advanced Technology in India. Three jacks support each of the 32-ton heavy, 15-meter long cryo-dipoles of LHC, and provide the required alignment features. The main requirements are a setting resolution of 0.05 mm, and a range of movement of 20 mm in the horizontal and 40 mm in the vertical direction. Each jack has two degrees of controlled movement in the horizontal and vertical direction, whereas the remaining horizontal movement is left free. By a suitable choice of the layout of the three jacks, the full range of alignment of a cryo-magnet can be obtained. The design of the jacks evolved from a preliminary value analysis between various concepts, towards the complete engineering of the retained concept, selection of the most appropriate and cost-effective industrial production processes and setting-up of an effective quality assurance policy. Building and testing of 36 prototype jacks allowed an extensive experimental validation of their performance at CERN, where they were operated in the String 2 facility, and yielded an improved understanding for cost-effective steering of the production processes before launching the series production. Presently, the mass production of the jacks is in progress with two Indian manufacturers, and some 1500 jacks have already been delivered to CERN. Considering the successful performance of the jacks, it is now envisaged to extend the use of the same type of jacks to provide the even higher-demanding alignment of the low-beta quadrupoles of LHC.
|
|