18
Vib ti St bilit Of NSLS II Gi d Vibration Stability Of NSLS II Girder- Magnets Assembly MEDSI June 10, 2008 V. Ravindranath S. Sharma, A. Jain, P. He, L. Doom, F. Lincoln N ti lS h t Li ht S II National Synchrotron Light Source II Brookhaven National Laboratory 1 BROOKHAVEN SCIENCE ASSOCIATES

Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

  • Upload
    others

  • View
    2

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets Assembly

MEDSI June 10, 2008

V. Ravindranath

S. Sharma, A. Jain, P. He, L. Doom, F. Lincoln

N ti l S h t Li ht S IINational Synchrotron Light Source II Brookhaven National Laboratory

1 BROOKHAVEN SCIENCE ASSOCIATES

Page 2: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Outline

f f• Introduction-tolerance specifications for stability and design approach for the NSLS-II girder.

• FEA modal analyses and experimental verificationFEA modal analyses and experimental verification

• Response of the girder system to ambient vibration

2 BROOKHAVEN SCIENCE ASSOCIATES

Page 3: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Introduction

• NSLS-II beam stability requirement: 10% or better of theminimum electron beam size → ± 0 3 microns verticallyminimum electron beam size → ± 0.3 microns vertically.

• For assuring beam stability stability of storage ring• For assuring beam stability, stability of storage-ringcomponents such as magnets, chambers, BPMs, girder arecriticalcritical

ToleranceLimits

ΔX RMS(nm)

ΔY RMS(nm)

Uncorrelated magnet motionwill lead to a closed orbit

lifi ti f 12 t th ID( ) ( )

Uncorrelatedmagnetmotion

< 150 < 25 amplification of ~12 at the IDcenter

motionUncorrelatedgirder motion

< 600 < 70

3 BROOKHAVEN SCIENCE ASSOCIATES

Page 4: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Girder Design Approach

100

1000

)

0.5-4 Hz-400 nm

1

10

cmen

t (nm

)

4 100 Hz

0.1

1

RM

S di

spla

c 4-100 Hz -15 nm

0.001

0.01

0 10 20 30 40 50 60 70 80 90 100

R

RMS displacement for NSLS-II:

0 10 20 30 40 50 60 70 80 90 100

Freq (Hz)

0.5-4 Hz = 400 nm4-100 Hz = 15 nmF 30 H d ti 1

4 BROOKHAVEN SCIENCE ASSOCIATES

Frequency > 30 Hz, ground motion < 1 nm

Page 5: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Conceptual Design- Multipole Girder

• 1” thick1 thick stiffeners welded to the girder to

1.2 m

minimize torsion

5 m0.86 m

• Girder fabrication : Commercial plates 1-2” thick, welded• Internal ribs to enhance stiffness and minimize torsion

0.86 m

te a bs to e a ce st ess a d e to s o• Girder support : Eight locations, 2” diameter bolts• Girder design was optimized by carrying out FEA modal analysis

5 BROOKHAVEN SCIENCE ASSOCIATES

Page 6: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Girder Prototype For Vibration Tests

• Goal:To verify and if needed calibrate the FEA model, so that it is applicable to all future analysesto all future analyses

• Location: Section 4 of the NSLS-IIstorage ring Girder weight ~7000 lbsstorage ring. Girder weight ~7000 lbsand supported magnets weight ~ 7000lbs

SECTION 2 SECTION 3SECTION 4 SECTION 5 SECTION 6

3.2 m2.9 m3.6 m5.0 m

3.6 m

One cell of the NSLS-II storage ring

6 BROOKHAVEN SCIENCE ASSOCIATES

Page 7: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Vibration sensorGround motion 1.E+00

Accelerometer

1.E-01

ons)

Geophone

4-100 Hz

1.E-02cm

ent (

mic

ro

30 nm

1.E-03

RM

S di

spla

1.E-040 10 20 30 40 50 60 70 80 90 100

PCB accelerometers, Model# B393B04

Freq (Hz)

Vibration sensors : PCB accelerometers versus Geophone

Model# B393B04

7 BROOKHAVEN SCIENCE ASSOCIATES

Geophone

Page 8: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Vibration Study-Sequence

DUMMY WEIGHTS3. GIRDER-

WEIGHTS

GIRDER 1. FREE

WEIGHTS

GIRDER 1. FREE GIRDER

2 SUPPORTEDSUPPORTS

2. SUPPORTED GIRDER

8 BROOKHAVEN SCIENCE ASSOCIATES

Page 9: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Modal Analysis – FREE GIRDERy

1.00E+00

1.00E+01GROUND

Girder_left

Girder_right

First natural freq = 38 Hz

Second natural freq = 50 Hz

Bending mode 42 Hz

1.00E-02

1.00E-01

sqrt

(Hz)

) Twisting mode freq = 116 Hz

Second natural freq = 50 Hz

1 00E 04

1.00E-03PS

D (m

icro

n/s

Bending mode 58 Hz

1.00E-05

1.00E-04

1.00E-060 20 40 60 80 100 120 140 160 180 200

Freq (Hz)Twisting mode = 112 HzImpact testing: Horizontal impulse excitation provided byImpact testing: Horizontal impulse excitation provided by a soft-tipped hammer.Peaks in the PSD curve –natural frequenciesGood agreement between FEA and experiment

9 BROOKHAVEN SCIENCE ASSOCIATES

Good agreement between FEA and experiment

Page 10: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Phase Correlation For The Free Girder

120140160180200

406080

100120

eg) 38 Hz phase = 0 Deg

-60-40-20

020

Phas

e (D

eBending mode-42 Hz

160-140-120-100-80-60Bending mode 42 Hz

-200-180-160

0 15 30 45 60 75 90 105 120 135 150

F (h )

116 Hz phase = 180 Deg

Freq (hz)

Twisting mode-112 Hz • Measured phase correlation agrees with the

mode shapes predicted by FEA

10 BROOKHAVEN SCIENCE ASSOCIATES

Page 11: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Modal Analysis - Supported Girder

90

100

y (H

z)

70

80

Freq

uenc

y

40

50

60

1st M

odal

MODE I = 125 HZ 400 200 400 600 800 1000 1200 1400 1600 1800 2000

Torque (ft-lbs)

MODE I = 125 HZ

• Experimental observation: Natural frequency depends on the tightening torque on the threaded bolt supports

MODE I = 157 HZ

• First natural frequency increased from 40 Hz to 85 Hz, as the torque increased up to 1000 ft-lbs

• Beyond 1000 ft-lbs the effect is not very significant - 5

11 BROOKHAVEN SCIENCE ASSOCIATES

MODE I = 157 HZ Beyond 1000 ft lbs the effect is not very significant 5 Hz at 2000 ft-lbs

Page 12: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

FEA Model Calibration

Young’s modulus of the 2” bolt

• With the modification, the modal analysis

reduced by a factor of 10

ROCKING MODE yresults agree better with the measured natural frequency of the girder at 1000 ft-

ROCKING MODE

lbs

• FEA Rocking mode = 86 Hz (Measured →85 Hz)

• FEA Twisting mode = 110 Hz (Measured →120 Hz)TWISTING MODE

12 BROOKHAVEN SCIENCE ASSOCIATES

120 Hz)TWISTING MODE

Page 13: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Girder - Weights

1.00E+00

1.00E+01Weight_LeftWeight_CenterWeight_Right

MODE 1 ~40 Hz

1 00E-02

1.00E-01

on/s

qrt(H

z)

Girder_LeftGirder_CenterGirder_Right

~40 Hz

1.00E-03

1.00E-02

PSD

,mic

ro

1.00E-05

1.00E-04

0 20 40 60 80 100 120 140 160 180 2000 20 40 60 80 100 120 140 160 180 200

Freq, Hz

• Modal analysis of the adjusted girder model with 5000 lbs weight5000 lbs weight

• FEA Rocking mode:45 Hz (Measured → 40 Hz)

• FEA Twisting mode:56 Hz (Measured → 60 Hz)

13 BROOKHAVEN SCIENCE ASSOCIATES

Page 14: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Modal Analysis - Girder- Magnet Assemblyy g y

• The calibrated model was used to estimate the natural frequencies of the final girder-magnet system

• FEA Rocking mode = 34 HZ

• FEA Twisting mode = 51 HZ

14 BROOKHAVEN SCIENCE ASSOCIATES

Page 15: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Vertical Power Density Spectra

1 00E+00

1.00E+01Dummy weight

Girder

1.00E-01

1.00E+00

qrt(H

z)

Ground

1.00E-03

1.00E-02

PSD

,mic

ron/

sq

RMS Displacement (4-100 Hz), nm

1.00E-04

Ground nm

Girder, nm (Amp.Fac)

Weight, nm (Amp. Fac)

1.00E-051 10 100

Freq, Hz

• * N i i t f th t t 79.0* 79.8 (~1) 83.3 (~1)• * Noisy environment for the test

• Expected ambient motion (4-100 Hz) for NSLS-II ~15 nm

15 BROOKHAVEN SCIENCE ASSOCIATES

Page 16: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Horizontal Power Density Spectra

1.00E+00

1.00E+01Dummy Weight

Girder

G d

1.00E-01

/sqr

t(Hz)

Ground

1.00E-03

1.00E-02

PSD

,mic

ron/

1 00E 05

1.00E-04 RMS Displacement (4-100 Hz), nmGround Girder nm Weight nm1.00E-05

1 10 100Freq, Hz

Ground nm

Girder, nm (Amp.Fac)

Weight, nm (Amp. Fac)

40.3 46.0 (~1) 81 1 (~2)*• *Dummy weights not secured firmly on the ( ) 81.1 ( 2)girder

• Expect lower amplification for the magnets-bolted to the girder

16 BROOKHAVEN SCIENCE ASSOCIATES

bolted to the girder

Page 17: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Conclusion

• For the final girder-magnet assembly first two natural frequencies are 34 Hz Tolerance

LimitsΔXRMS

ΔYRMS q

(Rocking mode) and 51 Hz (Twisting mode)

• Tolerance on the uncorrelated magnet

Limits RMS(nm)

RMS(nm)

Uncorrelatedmagnet

< 150 < 25Tolerance on the uncorrelated magnet motion can be easily met:

– Girder transmits ground motion without any amplification in 4-100 Hz (horizontally

magnetmotionUncorrelatedgirder motion

< 600 < 70any amplification in 4-100 Hz (horizontally and vertically)

– On top of the dummy weights, Amplification of the vertical ground

girder motion

RMS displacement for Amplification of the vertical ground motion ~1

– The anticipated ambient motion for NSLS-II in 4-100 Hz is 10 times smaller than the

pNSLS-II:

0.5-4 Hz = 400 nmhorizontal tolerance

– The tolerance requirements can be met

4-100 Hz = 15 nm

17 BROOKHAVEN SCIENCE ASSOCIATES

Page 18: Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder- Magnets Assembly · 2017-03-30 · Vib ti St bilit Of NSLS II Gi dVibration Stability Of NSLS II Girder-Magnets

Thank You !Thank You !

18 BROOKHAVEN SCIENCE ASSOCIATES