HQ test at CERN:

strain and stress measurements

H. Bajas, A. Chiuchiolo

02/09/2012 Hi-Lumi special session on HQ test results

I. Summary of the HQ01-e mechanics during its service life

II. Detail analysis of the stress/strain behaviour during operation

OUTLINE

I. Summary of the HQ01-e mechanics during its service life

II. Detail analysis of the stress/strain behaviour during operation

OUTLINE

H. BAJAS | Hi-Lumi special session on HQ test results 4

I. Summary of the HQ01-e mechanics during its service life

Good agreement with measurement from [Ferracin 2012] and coherence from expectation.Low spread from SGs of different positions.

02/09/2012

STRESS history

Az Ax Ax Az Ax Az Ax Ax Az Ax Az Ax Ax Az Ax Az Ax Ax Az Ax

ShellRod Pole Shell

Rod Pole Shell

Rod Pole Shell

Rod Pole

Warm 1st Cooldown 2nd CooldownLast quench @ 1.9

K

-175-150-125-100

-75-50-25

0255075

100125150175200

LBNLT, A, or 9R, B, or 8B, C, or 7L, D, or 5st

ress

[Mpa

]

H. BAJAS | Hi-Lumi special session on HQ test results 5

Az Ax Ax Az Ax Az Ax Ax Az Ax Az Ax Ax Az Ax Az Ax Ax Az AxShell Rod Pole Shell Rod Pole Shell Rod Pole Shell Rod Pole

Run 1 @ 4.2 K Run 1 @ 1.9 K Run 2 @ 4.2 K Run 2 @ 1.9 K

-30

0

30

60

90

120

150

180

210

T, A, or 9R, B, or 8B, C, or 7L, D, or 5

stre

ss [M

pa]

Good stability of the stresses for SHELL and RODS for the 55 quenches.Critical positive stress measurements at the POLES.

02/09/2012

I. Summary of the HQ01-e mechanics during its service lifeSTRESS at quenches

I. Summary of the HQ01-e mechanics during its service life

II. Detail analysis of the stress/strain behaviour during operation

OUTLINE

H. BAJAS | Hi-Lumi special session on HQ test results 7

0 50 100 150 200 250 300600

800

1000

1200

1400

1600

1800

2000

2200

Temperature [K]

stra

in[

st

rain

]

Cooldown 300K - 1.9KRods axial

RAZRBZRCZRDZ

0 50 100 150 200 250 300600

800

1000

1200

1400

1600

1800

2000

2200

Temperature [K]

stra

in[

s

trai

n]

Warm up 1.9K - 300KRods axial

RAZRBZRCZRDZ

Rods axial

1262 mɛ 1277 mɛ

Temperature range: 291K - 1.9K

Cool-down

Warm-up

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

Rods axial

COOLDOWN: Detail STRAIN analysis of shell and rods

H. BAJAS | Hi-Lumi special session on HQ test results 8

0 50 100 150 200 250 300-400

-200

0

200

400

600

800

Temperature [K]

stra

in[

st

rain

]

Cooldown 300K - 1.9KShell Axial

SHTZSHRZSHBZSHLZ

0 50 100 150 200 250 300-400

-200

0

200

400

600

800

Temperature [K]

stra

in[

st

rain

]

Warm up 1.9K - 300KShell Axial

SHTZSHRZSHBZSHLZ

Shell axial

0 50 100 150 200 250 300800

1000

1200

1400

1600

1800

2000

2200

Temperature [K]

stra

in[

st

rain

]

Cooldown 300K - 1.9KShell Azimuthal

SHTTSHRTSHBTSHLT

0 50 100 150 200 250 300800

1000

1200

1400

1600

1800

2000

2200

Temperature [K]

stra

in[

s

trai

n]

Warm up 1.9K - 300KShell Azimuthal

SHTTSHRTSHBTSHLT

511 mɛ 534 mɛ

990 mɛ 1018 mɛ

Cool-down

Cool-down

Warm-up

Warm-up

02/09/2012

Shell azimuthal

II. Detail analysis of the stress/strain behaviour during operationCOOLDOWN: Detail STRAIN analysis of shell and rods

H. BAJAS | Hi-Lumi special session on HQ test results 9

Pole axial

0 50 100 150 200 250 300

-300

-250

-200

-150

-100

-50

0

50

100

150

Temperature [K]

stra

in[

st

rain

]

Cooldown 300K - 1.9KCoils Axial

C08ZC07ZC05Z

0 50 100 150 200 250 300

-300

-250

-200

-150

-100

-50

0

50

100

150

Temperature [K]

stra

in[

s

trai

n]

Warm up 1.9K - 300KCoils Axial

C08ZC07ZC05Z

0 50 100 150 200 250 300

-1200

-1100

-1000

-900

-800

-700

-600

-500

-400

-300

-200

Temperature [K]

stra

in[

st

rain

]

Cooldown 300K - 1.9KCoils Azimuthal

C09TC08TC07TC05T

0 50 100 150 200 250 300

-1200

-1100

-1000

-900

-800

-700

-600

-500

-400

-300

-200

Temperature [K]

stra

in[

s

trai

n]

Warm up 1.9K - 300KCoils azimuthal

C09TC08TC07TC05T

189 mɛ 230 mɛ

608 mɛ 639 mɛ

Cool-down

Warm-up

Warm-up

Cool-down

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

Pole azimuthal

COOLDOWN: Detail STRAIN analysis of the poles

H. BAJAS | Hi-Lumi special session on HQ test results 10

Computation of the stress from strains in both directions assuming friction-less and elastic behaviour:

)()1( 2 axazaz

E

)()1( 2 azaxax

E

axax E

STRESS to STRAIN computation

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

E = 79 GPa and n = 0.34 for Aluminum (Shell and Rods)E = 130 GPa and n = 0.3 for Titanium (Poles)

Shell and Pole Rods

H. BAJAS | Hi-Lumi special session on HQ test results 11

Small spread with different locations for shell azimuthal more for the axial direction.

Same slope for shell and rods: 0.013 [MPa/kA2]

Relaxation with cycles (first vs. last):

• SHELL axial: Slight (<13%)• SHELL azimuthal: Marginal (<3%)• RODS axial: Marginal (<3%)

184 ± 11 MPa93 ± 15 MPa

163 ± 4 MPa

POWERING: Detail STRESS analysis of shell and rods

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

Right

BottomTop

Left

Right

Bottom

Top

Left

A, B, D

C

H. BAJAS | Hi-Lumi special session on HQ test results 12

Azimuthal: • Different offsets but linear behaviour • Same slope but for coil 7• Flattening for the 4 coils with current (> 15 kA)

and with number of quenches• Marginal relaxation with quenches ( < 3 % )

Axial: • Highly non linear• Significant relaxation with quenches

( > 50 % in C7&5, >10% in C9)

POWERING: Detail STRAIN analysis of the poles

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

C8 C7 C9 C5

C8

C7

C9

C5

C8

C7

C5

H. BAJAS | Hi-Lumi special session on HQ test results 13

Linear behaviour (slope: 0.75 MPa/kA2)for azimuthal (0.21 for axial).

Azimuthal stress beyond 0 Mpa shows proof of cable/pole de-bounding at high current > 15 kA.

Relaxation with quenches:• azimuthal: Marginal ( < 3 %)• axial: Significant ( > 20 %)

POWERING: STRESS analysis of the poles

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

C5

C7 & 8

C5

C7 & 8

C7

C5 & 8

H. BAJAS | Hi-Lumi special session on HQ test results 14

Detail axial STRAIN analysis of the poles

0 50 100 150 200 250 300-120

-110

-100

-90

-80

-70

-60

-50

I2 [kA2]

stra

in [

s

trai

n]

Training quenches @1.9 KCoil 5Z axial

q1q2q4q5q6q7q8q9q10q12q14q15q16q17q18q19q20q21q22q23q24q25q26q27q28q29q30q31

0 50 100 150 200 250 300-80

-70

-60

-50

-40

-30

-20

I2 [kA2]

stra

in [

stra

in]

Training quenches @1.9 KCoil 7Z axial

q1q2q4q5q6q7q8q9q10q12q14q15q16q17q18q19q20q21q22q23q24q25q26q27q28q29q30q31

Different behaviour between the three Coils (5, 7, 8) due to Lorentz force loading:

• C5 & C7 are compressed.• C8 extends.

0 50 100 150 200 250 300-270

-260

-250

-240

-230

-220

-210

-200

-190

I2 [kA2]

stra

in [

stra

in]

Training quenches @1.9 KCoil 8Z axial

q1q2q4q5q6q7q8q9q10q12q14q15q16q17q18q19q20q21q22q23q24q25q26q27q28q29q30q31

Ratcheting and non-linearity evidences:• Gradual sliding of the cable • Plasticity

First run @ 1.9 K

02/09/2012

II. Detail analysis of the stress/strain behaviour during operation

H. BAJAS | Hi-Lumi special session on HQ test results 15

0 50 100 150 200 250 300-35

-30

-25

-20

-15

-10

-5

0

5

I2 [kA2]

stra

in [

s

trai

n]

Training quenches @1.9 KCoil 7Z axial

q1q2q3q4q5q6q7q8q9q10q11q12q13

0 50 100 150 200 250 300-270

-260

-250

-240

-230

-220

-210

-200

-190

I2 [kA2]

stra

in [

s

trai

n]

Training quenches @1.9 KCoil 8Z axial

q1q2q3q4q5q6q7q8q9q10q11q12q13

The coil 7 is completely unloaded in the axial direction at the end of the test.

The coil 8 is more stable The warmup/cooldown brings it back to its initial position.

02/09/2012

Detail axial STRAIN analysis of the polesSecond run @ 1.9 K

II. Detail analysis of the stress/strain behaviour during operation

• Good control of the magnet structure mechanics (shell, rods, pole) with agreement between with FEM computation, LBNL 1st run and CERN 2nd and 3rd run. Presence of offset (physical or not ) but same slope.

• Good stability with warmup-cool-down and number of quenches

• Signs of cable/pole de-bounding (pole azimuthal stress beyon 0 MPa) at current greater than 15 kA with effect of the number of quenches.

• Signs of sliding and/or plasticity of the cable (strong relaxation of the pole axial strain)

• Can we link quenched coils (mostly 7&8) with the strain state of the pole?

• What is the actual strain of the cable around its pole (Ic(B,T,e))?

conclusion

02/09/2012 H. BAJAS | Hi-Lumi special session on HQ test results 16