ECAL End Cap Dee Assembly, Transport, InstallationCERN January 2006AR / RJSG – 1 Alexandre Riabov (IHEP, Protvino) Justin Greenhalgh (RAL) Finite Element

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Dee Assembly, Transport, Installation CERN January 2006 AR / RJSG – 1

Alexandre Riabov (IHEP, Protvino)

Justin Greenhalgh (RAL)

Finite Element Analysis of Dee with fixed reinforcing beam.

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General IssuesGeneral Issues

• This work is based on the note “Request for calculation of effect of reinforcing beam on Dee backplates” (EE/358/RJSG/2004) by Justin Greenhalgh and preliminary results presented in the note “FE analysis of Dee with reinforcing beam” (EE/445/RJSG+AR/2005)

• Two Extreme variants which can be realized at SC assembly and Dee transportation stages have been considered. Along with the natural gravitation the Dee can be exposed to an additional acceleration of 0.35g in all directions which is equal to the static equivalent seismic load. Maximal braking accelerator allowed is 1g. The worst combined load cases are (X-axis is vertical, Z-axis is perpendicular to Dee plane, Y-axis is in a transportation direction - see pictures for explanation of the global coordinate system of the model) :

E1: Accel=(1.35, 1, +0.35) g

E2: Accel=(1.35, 1, -0.35) g

• At installation stage the worst combination of gravity and seismic loads is described by accelerating load vector (here Y-axis becomes vertical, and X-axis – horizontal):

E3: Accel=(0.35, 1.35, 0.35) g

• Additional load case C7 without seismic loads is also have been considered:

C7: Accel=(0, 1.35, 035) g

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Questions.Questions.

• Displacements and Stresses in the aluminum of the backplate;

• Stresses in the steel of the brackets and reinforcing beam;

• Axial forces in all bolts; Shear forces in all dowels (pins);

• Reaction forces on the reinforcing beam and the brackets bolts from the direction of the OPAL frame;

• Loss of SC clearance. Where does the maximum loss occur?

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The full FE ModelThe full FE Model

Support ring (SR) Brackets (BR)

Reinforcing Beam

Backplate (BP)

Supercrystals (SC)

Global CS (X,Y,Z)

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Backplate detailsBackplate details

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BR details and some definitionsBR details and some definitions

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SC ArrangementsSC Arrangements

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Boundary conditionsBoundary conditions

Beam ends fixed

Brackets fixed

Coupling between the model parts (bolts and pins)

Loading: Acceleration vector A=(αx, αy, αz) g

g

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E1: BP&SC displacementsE1: BP&SC displacements

Result: The maximal displacements of BP are very low ~ 0.9 mm

Assembly/Transp.

A=(1.35, 1, 0.35) g

Beam ends fixed

Last BR removed

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E1: Von Mises Stresses in BPE1: Von Mises Stresses in BP

Assembly/Transp.

A=(1.35, 1, 0.35) g

Beam ends fixed

Last BR removed

Result: The stress concentration is ~ 56 MPa. Overall stress is low

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E1: Brackets displacementsE1: Brackets displacements

Assembly/Transp.

A=(1.35, 1, 0.35) g

Beam ends fixed

Last BR removed

Result: The maximal displacements are low ~ 0.2 mm (reached for -70ºBR)

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E1: Von Mises Stresses in BRsE1: Von Mises Stresses in BRs

Assembly/Transp.

A=(1.35, 1, 0.35) g

Beam ends fixed

Last BR removed

Result: The stress concentration is ~ 40 MPa. It’s very low for steel

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E1: Reinforcing Beam StressesE1: Reinforcing Beam Stresses

L-Beam (LB)

L-Section (LS)

Assembly/Transp.

A=(1.35, 1, 0.35) g

Beam ends fixed

Last BR removed

Result: The stress concentration is ~ 170 MPa. It occurs near LS-LB bolts

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E1: Stresses in Support RingE1: Stresses in Support Ring

Assembly/Transp.

A=(1.35, 1,0.35) g

Beam ends fixed

Last BR removed

Result: The stress concentration is ~ 40 MPa. It occurs at SR-BP bolts

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Result: The maximal displacements of BP and SCs are very low ~ 0.55 mm

Assembly/Transp.

A=(1.35, 1,-0.35) g

Beam ends fixed

Last BR removed

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Result: The stress concentration is ~ 32 MPa. It occurs near BP-BR bolts

Assembly/Transp.

A=(1.35, 1,-0.35) g

Beam ends fixed

Last BR removed

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Result: The stress concentration is ~ 98 MPa. It is not critical for the steel

Assembly/Transp.

A=(1.35, 1,-0.35) g

Beam ends fixed

Last BR removed

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E2: Reinforcing Beam StressesE2: Reinforcing Beam Stresses

Result: The stress concentration is ~ 56 MPa. It occurs in L-section

Assembly/Transp.

A=(1.35, 1,-0.35) g

Beam ends fixed

Last BR removed

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Installation

A=(0.35,1.35,0.35)g

Beam removed

Last BR removed

Result: The maximal displacements of BP are rather large ~ 8.6 mm

Large displacements are due to Z-direction seismic load. This may be dangerous from the point of view loss of SC clearance.

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Installation

A=(0.35,1.35,0.35)g

Beam removed

Last BR removed

Result: The stress concentration is ~ 103 MPa. It occurs near BP-BR bolts

For the Aluminium σyield = 270 MPa.

The safety factor is 0.9*(270/103) = 2.4.

Overall stress is small- it is not greater than 40MPa

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E3: Bracket displacementsE3: Bracket displacements

Result: The maximal displacements is ~ 1.4 mm for the lower bracket.

Installation

A=(0.35,1.35,0.35)g

Beam removed

Last BR removed

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Installation

A=(0.35,1.35,0.35)g

Beam removed

Last BR removed

Result: The stress concentration is ~ 330 MPa. The Steel of BRs should be good

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C7: BP displacementsC7: BP displacements

Installation

A=(0,1.35,0)g

Beam removed

Last BR removed

No seismic

Result: Without seismic the displacements are small: ~ 0.7 mm.

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Loss of CS clearance in DeeLoss of CS clearance in Dee

Result: Variant E3 may be problematic

It was suggested (RJSG) to consider the value of 0.18 mm as a worrying limit for loss of clearance between supercrystals in a Dee. From this one can conclude that a worrying limit for loss of clearance between SCs centers of masses is 0.18/(400/300) = 0.135 mm.

Here: 400mm – length of the SCs, 300mm – the distance of the SCs mass centers from the BP

Next table presents maximal loss of clearance, SC pair for which this maximum occurs, and the number of SCs pairs with Loss ≥ 0.135 mm.

For detailed results see files Case_*.doc.

Case : (accel) Maximal Loss of Clearance [mm] /SCs pair for which it’s reached

Number of problematic SC pairs(Loss ≥ 0.135 mm)

E1 : (1.35,1, 0.35) 0.144 / (B2M, C2M) 1

E2 : (1.35,1,-0.35) 0.019 / (B2, B3) 0

E3 : (0.35,1.35,0.35) 0.353 / (C1, C2) 46

C7 : (0,1.35,0) < 0.075 for all SCs 0

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Forces in BP-BR bolts and pinsForces in BP-BR bolts and pinsCase E1: Acce l=(1.35,1,0.35) g

-2

-1

0

1

2

3

4

5

6

7

8

-80 -60 -40 -20 0 20 40 60 80

Bracket pos ition [degree]

Fo

rce

[k

N]

Lef t Bolt

Right Bolt

Pin

Case E2: Acce l=(1.35,1,-0.35) g

-2

0

2

4

6

8

10

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

Lef t Bolt

Right Bolt

Pin

Case E3: Accel=(0.35,1.35,0.35) g

-25

-20

-15

-10

-5

0

5

10

15

20

-80 -60 -40 -20 0 20 40 60 80

Bracket position [degree]

Fo

rce

[k

N]

Lef t Bolt

Right Bolt

Pin

Case C7: Accel=(0,1.35,0) g

-10-8-6-4-202468

10

-80 -60 -40 -20 0 20 40 60 80Bracket position [degree]

Forc

e [k

N]

Left Bolt

Right Bolt

P in

For bolts: positive value denotes tension, negative – compression. For pins shear forces are given.

Result: For all cases forces are acceptable. Maximal axial force is ~ 9 kN,

maximal shear force is ~ 15 kN

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Forces in LS-BP bolts and pinsForces in LS-BP bolts and pinsCase E2: Acce l=(1.35,1,-0.35)

-10

-8

-6

-4

-2

0

2

4

6

8

10

12

-1600 -1200 -800 -400 0 400 800 1200 1600

Y-pos ition of LS-BP bolts and pins [m m ]

Fo

rce

[kN

]

Bolts

Pins

Case E1: Accel=(1.35,1,0.35)

-20

-15

-10

-5

0

5

10

15

20

-1600 -1200 -800 -400 0 400 800 1200 1600

Y-position of LS-BP bolts and pins [m m ]

Fo

rce

[kN

]

Bolts

Pins

Result: Maximal forces are due to braking and they occur at one of the L-beam ends. Maximal reaction force is about 4.5 tons.

Result: The LS-BP bolts practically do not work. Maximal shear force is about 1.5 tons. It is due to Braking.

Reaction forces [kN] Force Moments [kN∙m]

Case Y-pos RX RY RZ MX MY MZ

E1 1700 -3.81 6.45 -13.98 -15.57 -0.15 7.41

-1700 -19.29 -36.69 -18.69 21.93 -0.31 -29.78

E2 1700 2.53 -9.79 -1.19 -1.47 0.03 -3.15

-1700 -12.95 -20.45 -5.90 7.83 -0.13 -19.21

This table presents reaction forces and moments on the beam ends from OPAL frame

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Case E1: Axial Forces in BR-FR bolts

-5

-4

-3

-2

-1

0

1

2

3

4

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case E1: ShearForces in BR-FR bolts

0

1

2

3

4

5

6

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case E2: Axial Forces in BR-FR bolts

-15

-10

-5

0

5

10

15

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case E2: ShearForces in BR-FR bolts

0

2

4

6

8

10

12

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

E1&E2: BR-OPAL frame boltsE1&E2: BR-OPAL frame bolts

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E3&C7: BR-OPAL frame boltsE3&C7: BR-OPAL frame boltsCase E3: Axial Forces in BR-FR bolts

-40

-30

-20

-10

0

10

20

30

40

50

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case E3: Shear Forces in BR-FR bolts

0

5

10

15

20

25

30

35

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case C7: Axial Forces in BR-FR bolts

-15

-10

-5

0

5

10

15

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

Case C7: Shear Forces in BR-FR bolts

0

2

4

6

8

10

12

-80 -60 -40 -20 0 20 40 60 80


Fo

rce

[kN

]

LW right

LW lef t

UP right

UP lef t

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ConclusionsConclusions• Fixing of the reinforcing beam ends to the OPAL frame fully solves all mechanical problems

which can arise at stages of the Dee assembly and transportations. The deflections and stresses in all parts of the construction are small, the loss of the SC clearance lies within specified limits (0.18 mm).

• At the stage of installation seismic load acting in the direction perpendicular to the backplate plane produces rather large deflections (up to 8.6 mm) and consequently rather large stresses in the backplate (~ 100 MPa) and in the brackets (~ 330 MPa). It should be noted that it is the stress concentration which arises locally. Overall stresses are much less. Nevertheless the mechanical quality of materials of the backplate and the brackets should be good enough. The loss of SC clearance in the Dee can reach 0.47 mm.

• In case of seismic absence (Case C7) the stress concentrations do not exceed 60 MPa in the backplate and 85 MPa in the brackets. The losses of SC clearance in a Dee are negligible - for all SC pairs the losses do not exceed 0.1 mm.

• We can not make true conclusions about the loss of SC clearance between Dees without performing additional calculations. The question is that during the installation of one Dee which is supporting by the brackets the another Dee has already installed in operational position and it is supported by the support flange (on HE). So the Dees are under different boundary conditions and additional calculations should be done for the Dee in the operational mode. We can only present here the maximum displacements of the A-column SCs towards to another Dee: they are ~1.95 mm for the E3 load case and only 0.27 mm for the C7 load case.

Documents

ECAL End Cap Dee Assembly, Transport, InstallationCERN January 2006AR / RJSG – 1 Alexandre Riabov (IHEP, Protvino) Justin Greenhalgh (RAL) Finite Element