Triplet string test bld 181
F.Micolon (TE-MSC-CMI) – TE-MSC SLM 20.09.19
In this presentation we will aim to:
• Review the latest results of the “additional tie rod” triplet consolidation proposal (overall stiffness gain and realignment issue).
• Review it’s implementability in the tunnel
• Review the proposed consolidation procedure
Bolted to flange (no welds)
Clamped to W-bellow
1x additional rod (top)
2x additional rod (top and bottom – symmetrical)
Building cool down
Radial
realignment of string
-7.4mm
-1.3mm
-5.6mm
-1.0mm -0.7mm
-3.1mm
-4.4mm -1.6mm -2.4mm
Interconnection contraction after realignment:
Q3DFBX = -2.4 mm Q2Q3 = -2 mm
Q1Q2 = -3 mm
Radial realignment of string Building cool down
-7.2mm -4.4mm -2.6mm
Release Q1Q2 extra rod Release Q2Q2 extra rods + radial realignment of string
-10.0mm -5.9mm -2.6mm
Interconnection contraction after realignment:
Q1Q2 Q2Q3 Q3DFBX Total
Without extra rods 4.1 mm 3.3 mm 2.5 mm 10 mm
• By comparing the tie-rod force values with and without the additional tie-rod we see that
• The extra tie-rod of the Q1Q2 interconnection is taking around 2.4t of longitudinal load (~33% of the vacuum load)
• The 2x extra tie-rods of the Q2Q3 interconnection were taking 3.5 t of longitudinal load in total (~45% of the vacuum load together)
• Overall the stiffness gain in the configuration tested is about 25%.
• With the interconnects Q1Q2 and Q2Q3 equipped with 2x extra rods, we would have a Q1 displacement limited to
around 6.5 mm instead of 10 mm.
significant realignment constraint.
• In order to check this, we carried out a series of vertical movement of the Q1 and Q2
magnets. In particular on the jack close to the interconnect (jack B) to see the effect of a
magnet misalignment on the jack load required to realign.
Friction in Jack
Friction in Jack
The current tie-rods add another 50 kg/mm of transverse stiffness (+25%).
The same conclusions applies under vacuum with a similar overall stiffness (~250kg/mm).
Q2B :
• If 2x additional tie-rods are installed on the Q1Q2 and Q2Q3 interconnects, the overall triplet stiffness could improve by up to 35% with a Q1 NIP movement of ~6.5mm
• Realignment is not hindered by the new tie-rod configuration in a measurable way.
The main contributor to the transverse stiffness is the W-bellow.
This solution is significantly improving the triplet stiffness without adding significant
functional constraints. The implementation is relatively easy and reversible.
• This week a general inspection of the LHC triplet was done to see if possible to implement the additional tie-rod solution underground.
The foreseen places where the tie-rod implementation looks possible has been marked directly on the flanges.
A strictly symmetric implementation is not possible – however the installation asymmetry is limited.
Minor design of the bolted ear modifications will be required
Corridor QRL
Bottom
Side flange Tie-rod DN200 flange routing
Q3R5 IP Top
Tie-rod routing zone
Vacuum instrum flange
Wire position system (WPS) routing
Corridor QRL
Bottom
Q2R5 NIP Top
Tie-rod routing zone Vacuum instrum flange
Wire position system (WPS) routing
Corridor QRL
Bottom
Side flange Tie-rod DN200 flange routing
zone
Q3R5 IP Bottom
Corridor QRL
Bottom
Side flange DN200 flange
Q2R5 NIP Bottom
Tie-rod routing zone
Corridor QRL
Bottom
Q2R5 IP Top
Tie-rod routing zone
Vacuum instrum flange
Corridor QRL
Bottom
Q1R5 NIP Top
Tie-rod routing zone Vacuum instrum flange
Corridor QRL
Bottom
Side flange
DN200 flange
Q2R5 IP Bottom
Tie-rod routing zone
Corridor QRL
Bottom
Side flange DN200 flange
Q1R5 NIP Bottom
Tie-rod routing zone
flange and the existing tie-rod on top. We stay clear of the WPS equipment.
• At the bottom, space available is more limited between the accessory flange and the DN200 flange but still looks feasible.
In order to accommodate this, the new ear must be redesigned to use 2x (or 4x) flange screws with tie-rod in the middle
• However in the LSS5L, we may have an implementation problem.
Corridor QRL
Bottom
Q1L5 NIP Top
Short M10 stud
This is visible on Q1NIP and Q3IP (because of cold mass cartridges welding which deformed the flanges) This consolidation might not be
implementable at all on LSS5L in this case.
triplet LS2
F.Micolon – 16/09/2019
• Cette procedure decrit la marche a suivre pour implementer les
consolidations prevues suite aux problemes de realignement des aimants triplets pendant le run 2.
Pre-requis a l’intervention:
• Les triplets sont a la pression atmospherique
• Les bumpers ne sont pas en contact
• La distance longitudinale entre la position actuelle et la position cible est connue (donnee par les geometres).
Il est conseille de commencer par renforcer les point 2 et 8 pour ensuite proceder vers les point 1 et 5 qui sont plus actifs au niveau du rayonnement.
Liste non-exhaustive :
• Cle dynamometrique (Max≥200Nm)
• Douille de 36mm
• Embout CHC 10mm pour cle dynamo (pour vis M12)
• Cle de 46mm
• Embout 5 pans specifique pour realignement Jack LHC (contacter geometres si besoin)
• Cle et douille de 19mm
• Douille rallongee de 17mm (pour ecrou M10).
doivent toutes etre resserrees.
Avec la douille de 36 (M24) et la cle
dynamometrique, serrer les coupelles au couple de 200Nm ( ou superieur si
possible).
Visser l’ecrou de jack dans les jacks D (jack longitudinaux) jusqu’en butee.
Attention, une butee a bille (visible sur la photo) doit se trouver de chaque cote de l’ecrou pour un fonctionnement normal du systeme de realignement.
Attention une butee a bille doit se trouver entre l’ecrou et le contre- ecrou.
• Devisser les ecrous de tie –rod au niveau des
oreilles d’environ 10mm de chaque cote pour
liberer les interconnections.
En agissant sur l’ecrou de realignement, remettre l’aimant dans la position longitudinale initiale donnee par Survey.
(Sens inverse des aiguilles = deplacement vers IP).
L’utilisation d’un comparateur (visible sur la photo) est
conseillee. Au besoin il peut etre positionne sur le corps de jack.
Attention – le realignement se fera dans l’ordre Q3 – Q2 – Q1 pour eviter a tout moment un ecart trop grand entre les aimant qui pourrait endommager les elements d’interconnection
(PIMS).
Retirer les 3x vis M12 inox situees sous chaque oreille.
Certaines oreilles sont fixees avec des goujons M10 (aimant Q3 et Q1)
– dans ce cas ignorer cette etape pour les goujons M10 uniquement.
• Visser des vis M12 CHC de classe 12.9 (longueur 40mm) a la place des vis inox precedentes (Lien Bossard)
• Veiller a utiliser des rondelle large de durete ≥200Hv (lien Bossard)
• Veiller a graisser les vis avant insertion (graisse lien EDH)
• Serrer au couple de 120 Nm
• Les goujons M10 mentionnes a l’etape precedente devront etre
resseres au couple de 40Nm a l’aide de la douille de 17mm rallongee.
• Positionner les ecrou de part et d’autre de chaque tie-rod au contact a la main
• Une fois au contact, serrer de 1/8 tour avec la cle de 46mm
• Au niveau des marques sur la contre- bride, retirer les vis des contrebride inox et deplacer les clamps
d’interconnection.
Note: si des goujons M10 sont present au lieu des vis inox M12, essayer de les retirer. Si impossible a retirer, pas de consolidation possible.
• Visser des vis M12 CHC de classe 12.9 (longueur 70mm) a la place des vis inox precedentes (Lien Bossard)
• Veiller a utiliser des rondelle large de durete
≥200Hv (lien Bossard)
• Veiller a graisser les vis avant insertion (graisse lien EDH)
• Serrer au couple de 120 Nm
• Visser l’oreille additionnelles sur les manchette
d’interconnection a l’aide d’un clamp modifie et d’une vis CHC M12 de longueur 110mm (lien Bossard)
• Veiller a utiliser des rondelle de durete ≥200Hv (lien Bossard)
• Veiller a graisser les vis avant insertion (graisse lien EDH)
• Serrer au couple de 60 Nm.
• Utiliser la partie femelle de clamp d’interconnection.
Attention cette partie doit etre modifiee avant montage. La partie arriere doit etre decoupee sur une distance d’environ 15mm.
--> Attention cela ne fonctionne que si les tie-rod sont decoupes a la longueur de l’interconnection +20mm
• Positionner les ecrou de part et d’autre de chaque tie-rod au contact a la main
• Une fois au contact, serrer de 1/8 tour avec la cle de 46mm
• Lors de cette operation, la position de l’aimant ne doit pas varier de plus de 0.05mm par rapport a la position theorique fixee a l’etape 3 (utiliser un comparateur – idem etape 3).
• Tous ecrous de tie-rod sont en contact avec les oreilles et ne se devissent pas a la main.
• Les tubes raidisseurs sont monte serres sur leur tige-filetees
• Vis de contrebride M12 @120Nm (M10 @40Nm)
• Les noix des 3x jack D sont enlevees
• We have designed and proposed a solution that stiffens the triplet without adding any foreseeable detrimental effects.
• The implementation, although maybe not possible on every LSS, looks feasible with a limited intervention time.
• A draft of implementation procedure has been proposed herein
Q1 Q2 Q3 DFXB
IP side
Legend
Tie rods
Tie rod ears
Bellow (flexible)
Spiders(considered free longitudinally for small disp) Jacks (based on a tilting column principle -
free in the longitudinal direction – motorized In the radial/vertical direction)
Vacuum vessel
Magnet cold mass
Fixed point
Cartridge (rigid link between the CM and Vvessel)
Q1 (2,3)
Vertical
Longitudinal
Non-IP side
Beam axis
Beam axis
Q1 Q2 Q3 DFXB
IP
1) When the insulation vacuum is emptied, a vacuum force of 8T is applied on the end of Q1 (and on the DFBX) and is transmited to the DFBX through the tie-rods (leads to a cumulative motion of the cryostats).
Q1 He pressure
22 kN* Q3 He pressure
4 kN*
* Force values corresponding to the operational conditions
** Valid for point 1 and 5 (no superconducting D1)
Q1/Q2
IP
Vacuum force
80 kN Q1 net force = ~0 kN Q2 net force ~0 kN Q3 net force = -8kN 80 kN
Vacuum force 80 kN**
2) Cooling down the magnet will shrink the cold mass – which stretches the interconnection bellows – and produces a pulling force.
3) When the cold mass are filled with liquid Helium under pressure (nominal) pressure forces are generated when the cold mass flanges are not symmetrical (this is the case on Q1 & Q3).
Summing up the operational forces :
Q1 non-IP
motion Q2 non-IP
motion
Q3 non-IP motion
‘DFBX’ skeleton (fixed point)
Q3
Q2
Q1
WPS structure
Q3
Q2
Q1
Q1 WPS
Q2 Q1Q2 IP
Tie rod ear
Q1Q2 NIP Tie rod ear
Jack Q1D in contact @12.1 mm Margin ~2.6 mm
-9.5 mm
-5.8 mm -2.3 mm
The next morning
- vacuum has slightly degraded
-0.9 mm -0.3 mm
56
Q1 longi position Q2 longi position
Q3 longi position
~31C
~26C Back of envelope calculation:
The triplet is ~30m long – made of carbon steel (α=12um/m/K) Δx=12E-6*30*5=1.8mm
We observe ~1.5mm
-9.5 mm
During a radial realignment sequence, all magnet move further back…
After a radial realignment sequence +/-2mm radial for each magnet :
-0.9 mm -0.4 mm
-7.5 mm -3 mm
magnet has been carried out (without the tie-rods) in Bld 181 with measurement of the force required.
The friction load in the supporting system is in the order of 700kg for Q1.
When the vacuum force is on, a radial realignment will release some of the friction load and lead to an additional magnet backward displacement.
Venting
Load Q1D
Height vacuum vessel
2.87 T
-440 kg
2.42 T 3.23 T
2.49 T
3.16 T
Variation of ~750kg between the upward/ downward realignment
This is not stick slip but friction (magnet position always under control).
Very similar to the pattern seen in the tunnel.
-1.2 mm -1.2 mm -0.8 mm
Jack Q1D in contact
-2.1 mm -2.2 mm -1.3 mm
offset to their neutral position (=bump).
Thus many magnets had less than their design jack range before
coming in contact with their jack body.
A Q3 B A
C B A Q1
B Q2
BUMPER TIE-ROD A JACK
3.62T
8.973mm
8.988mm 8.984mm
3.42T
3.16T
2.36T -62um +62um
+32um +32um
-24um
-24um
-10um -5um
5L – Q1D
Courtesy of M.Sosin (EN/SMM)
Cryostat vertical motion
Load on the jack piston
The aim was to lower the cryostat by 0.011mm.
The loss of load was above 1T and no downward movement of the cryostat was seen.
IP
Jack reached the limit
position
5L – Q1D
Courtesy of M.Sosin (EN/SMM)
The jack in question is found blocked against its frame
No longer free longitudinally
Some load is transmitted to the frame (magnitude unknown)
Gap opened (~20mm)
IP
? What are the main contributors to the triplet longitudinal Stiffness
? Why did we see a drift in the longitudinal position (if any)
? Why do we see high load variation during realignment ?
? How can we consolidate the triplet so they can be realigned in the future
We make a string test to try to answer the following questions :
‘DFBX’ skeleton (fixed point)
Q1
Q2 WPS/DOMS
structure
End cover (Vacuum enclosure)
The DFBX skeleton deflection will be measured with DOMS
It allows the position control in the vertical direction and one transverse direction (the other transverse direction is free by design – see next slide).
Tilting is controlled by tightening the side nut
Top bearing
Tilting column
Bottom bearing Jack piston
Jack frame
Back to slide
Top bearing
Tilting column
Bottom bearing Jack piston
Jack frame
Tie-rod
W bellow
IP direction).
Back to slide
on each tie-rod the resulting stress is marginal but still within the plastic domain (650 MPa vs. 700 MPa for the ultimate strength).
The tie-rod displacement in this case is ~20mm.
The highest stress is found on the heavily plasticized M12 flange screws.
The risk at this stage is to lose the compression of the vacuum seals however.
Note : The stiffness predicted by the FE model was 25% higher than in reality. So the actual situation may be more marginal even.
Note 2: Some tie-rod ear flange were found to be assembled with
The additional tie-rod does not add a significant additional contribution to the overall stiffness.
Zone where Q2C becomes slightly loaded (~0.2t @0mm)
Under vacuum
