vibration and mechanical stability status and perspectives · 2015-01-27 · vibration and...
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Slide: 1
ISDD Friday Lecture, 9 April 2010
Vibration and mechanical stabilitystatus and perspectives
L. Zhang, M. Lesourd
Vibration: A rapid oscillation of a particle, particles, or elastic solid or surface, back and forth across a central position
The American Heritage® Science Dictionary
Slide: 2ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
FundamentalsHow to measure nm level of vibrationGround vibrationVibration of mechanical structureVibration propagationBeam stabilityVibration investigation
Vibration on the EXPH floorCooling flow induced vibrations
Summary and perspectives
Outlines
Slide: 3ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
30.5 31 31.5 32 32.5-150
-100
-50
0
50
100
150
time (s)
velo
city
(µm
/s)
Temporal velocity
VRMS=30.382 µm/s
0 20 40 60-150
-100
-50
0
50
100
150
time (s)
velo
city
(µm
/s)
Temporal velocity (Response to mass drop)
Fundamentals
Temporal domain Frequency domainFourier transform
twin
Some termsWindow length twinSampling rate (number of samples per second): fs=1/ΔtBandwidth: f<fmax=fs/CNyquist(CNyquist ≥ 2)Spectral resolution Δf=1/twin
FFT
0 20 40 60 80 10010-2
10-1
100
101
102
Frequency (Hz)
V sp (µ
m/s
)
Spectral velocity
IFFT(+phase)
Slide: 4ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Fundamentals
In frequency domain
3 frequency rangesLow ( f < 1 Hz)
Ocean wavesmicro seismic activities
Intermediate (1<f<100 Hz)Mechanical resonant frequenciesTraffic, machineoperations, water flow, wind,…
High ( f >100 Hz)Generated by small electro-mechanical structuresVibro-acousticMuch smaller level
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
dis
plac
emen
t (µm
)
3D spectral displacement at the ESRF site
VerticalNorth-SouthEast-West
Low frequency
Intermediate frequency
High frequency
Slide: 5ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Fundamentals
10-1 100 101 102101
102
103
Frequency (Hz)
Tran
sfer
func
tion
V/(m
/s)
Geophone L4C transfer function
gama0=0.283
gama=0.5gamacr=0.71
Sensors (transducers)Geophones (L4C: 285 V/(m/s), sensor noise < 80 pm (RMS) < dRMS-ESRF-Site/1000)Seismometers (Guralp CMG-3ESP: 0.03 ~ 50 Hz)Accelerometers (strong, high-f Vib.)Laser vibrometer (d & V, d (>2nm))Displacement sensors (capacitive,…)
Slide: 6ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
FundamentalsData acquisition systems (DAS)
OROS, RefTekStandalone or networkDynamical range (12 16 24 bits, 60 80 120 dB)Lowest input range: 17mV, 200mV (RT)Internal noise ~ 10-7:16 nV (RT) @ 200mV
10 pm (with geophone L4C)
Data processing systemsMatlab, SAC, Star,...OROS
GPS receiver
TCP/IP
TCP/IP
Server
Client
Vibration signal
DAS
Data baseArchiveData processing Data storage
GPS receiver
TCP/IP
TCP/IP
Server
Client
Vibration signal
DAS
Data baseArchiveData processing Data storage
Slide: 7ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Fundamentals
Measurement quantities
10-1 100 10110-2
10-1
100
101
102
103
Frequency (Hz)
spec
tral
acc
eler
atio
n (µ
m/s2 )
3D spectral acceleration at the ESRF site
VerticalNorth-SouthEast-West
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
dis
plac
emen
t (µm
)
3D spectral displacement at the ESRF site
VerticalNorth-SouthEast-West
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
vel
ocity
(µm
/s)
3D spectral velocity at the ESRF site
VerticalNorth-SouthEast-West
Displacement VelocityVelocity Acceleration
Spectra of Velocity Flatter than those of displacement, accelerationLess dynamic range requirement from DASOne operation (integration or differentiation) to obtain displacement or acceleration
Most convenient to measure velocity geophone widely used
integration differentiation
*(2πf ) /(2πf )
Slide: 8ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Fundamentals
Measurement quantities
10-1 100 10110-2
10-1
100
101
102
103
Frequency (Hz)
spec
tral
acc
eler
atio
n (µ
m/s2 )
3D spectral acceleration at the ESRF site
VerticalNorth-SouthEast-West
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
dis
plac
emen
t (µm
)
3D spectral displacement at the ESRF site
VerticalNorth-SouthEast-West
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
vel
ocity
(µm
/s)
3D spectral velocity at the ESRF site
VerticalNorth-SouthEast-West
Displacement Velocity Acceleration
Sensors vs frequency rangeVery low frequency range displacement sensors (positioning and alignment,…)Intermediate frequency range velocity sensors: geophone (seismology, geophysics, petroleum exploration,…)High frequency range accelerometers(industries: auto, aeronautics,..)
integration differentiation
*(2πf ) /(2πf )
Slide: 9ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
0 20 40 60 80 10010-2
10-1
100
101
102
Frequency (Hz)
V sp (µ
m/s
)
Spectral velocity
Temporal domainVelocity of unit mass: v(t)
Kinetic energy:
RMS of v(t):
FundamentalsPower Spectrum Density (PSD)
0 20 40 60 80 10010-4
10-2
100
102
Frequency (Hz)
PSD
((µm
/s)2 /H
z)
Power Spectrum Density
VRMS=30.385 µm/s
2)(21)( tvte =
∑=n
RMS tvn
V 2)(1
Frequency domainVelocity spectrum: V(f)Power spectrum density:(kinetic energy per unit of frequency interval)
ffVPSD
Δ=
2)(21
∫ ∗= dfPSDVRMS
∫ ∗= dfPSDPtotal
30.5 31 31.5 32 32.5-150
-100
-50
0
50
100
150
time (s)
velo
city
(µm
/s)
Temporal velocity
VRMS=30.382 µm/s
Slide: 10ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
FundamentalsPower Spectrum Density (PSD)
Independent of window length
Spectral displacement (velocity, acceleration): window length twindependantPSD : independent of window length twinPSD is appropriate for vibration spectra comparison
PSD
Spectral displacement
Slide: 11ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
How to measure nm vibrationCapacitive sensor test setup
A moving surface driven by a piezo-actuator generates a controlled displacement d(t) = A*sin(2ft)Capacitive sensor and Laser vibrometer measure simultaneously this controlled displacementTested sensors:― LION C7-C (resolution: pp=1.5nm,
rms=0.1nm, range 10um)― PI Seca (range 20 um)
Test setup with capacitive sensor
Laser vibrometer
Capacitivesensor
PiezoActuator
A*sin(2ft)
Slide: 12ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
57 58 59 60 61 62 6310-9
10-8
10-7
10-6
10-5
X: 60.01Y: 2.619e-006
Frequency in Hz
PSD
in μ
m2 /H
z VibrometerCapacitive
How to measure nm vibrationCapacitive sensor test results
Piezo-actuator generated d(nm) ~ 1*sin(2ft), f=60 Hz Resonance of the test assembly at 557 Hz excellent agreement between Laser vibrometerand capacitive sensorAt f=60Hz, all sensors measure PSD=2.6x10-6
μm2/Hz, Δf ~ 0.1HzdRMS ~ 0.5 nm dpeak ~ 0.7 nm
Consistent with Piezo-actuator delivered displacement
0 200 400 600 800
10-8
10-6
10-4
Piezo/Capacitive/Vibro tests - 60Hz-1mV-sine
Frequency in Hz
PSD
in μ
m2 /H
z
VibrometerCapacitive
557 Hz
Slide: 13ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
How to measure nm vibrationCapacitive sensor test results
In vibration measurementsCapacitive sensors (PI, Lion) can measure sub-nm (~100pm)Laser vibrometer can measure 1 nm when f>10Hz
In static measurementsCapacitive sensors (PI, Lion) can measure nm-range displacementLaser vibrometer can measure 10 nm
Laser vibrometer measurements sensitive to air refractive index variation (temperature, convection). This limits the measurement accuracy of the laser vibrometer.
Slide: 14ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibration Spectra in different sites(Accelerator centres et al. )
Ground vibration decreases with increase in frequency :
Displacement PSD ~ f-4
Spectral displacement ~ f-2
1E-12
1E-09
1E-06
0.001
1
1000
0.01 0.1 1 10 100f (Hz)
PSD
(µm
2 /Hz)
1.FNAL C0 2.FNAL B0 3.Elburn4.FNAL Numi 5.APS Sd E 6.ESRF S137.DESY HERA
1E-111E-091E-071E-050.001
0.110
1000
0.01 0.1 1 10 100f (Hz)
PSD
(µm
2 /Hz)
8.SLAC S109.CERN P410.Asse11.Moxa12.Ellerhoop
W. Bialowons & H. Ehrlichmann, DESY, 2003
PSD ~ f -4
Slide: 15ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationSpectra at ESRF site
Comparable spectrum in 3DA peak at 3Hz (site resonance)Vibration varies with time― Period of 24H, week
Typical values (in 1-100 Hz)― Day: dpp=1 μm, dRMS= 0.3 μm― Night: dpp=0.15 μm, dRMS= 0.05 μm
10-1 100 101
10-4
10-3
10-2
10-1
100
101
Frequency (Hz)
spec
tral
dis
plac
emen
t (µm
)
3D spectral displacement at the ESRF site
VerticalNorth-SouthEast-West
Varies with time
Slide: 16ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
LURE
SOLEIL
ESRF
peak-to-peak displacement (µm)
02468
101214
08/10/96 12:00 09/10/96 12:00 10/10/96 12:00 11/10/96 12:00time (dd/mm/yy hh:mm)
Ver
tical
at the ESRFat Orme des Merisiersat the SuperACO
0.14 Hz
0.07, 0.14 Hz
low frequency motion (0.03-1Hz)
Ground vibration
Slide: 17ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
d2sites in Paris=5 km
dParis-Grenoble=500 km
Ground vibration
Slide: 18ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationSeismic waves
P-wavePrimary (pressure)
S-wavesecondary (shear)
Rayleigh wave
Love wave
Body waves
Surface waves
Slide: 19ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationSeismic wavesCross-hole test to determine Soil properties
Wave emission by hammer shockMeasurement of wave propagation by geophonesDetermine P- and S- wave propagation speeds Vp & Vs from measurement resultsDetermine soil parameters― Poisson’s ratio
― Young’s modulus
E: a key parameters for EX2 golden slab design
)(22
22
22
sp
sp
VVVV
−
−=ν
2)1(2 sVE νρ +=
Emission Reception
Slide: 20ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationEarthquake measured at ESRF in 1994
Time : 14-Dec-1994, 9:56:17 - 9:57:30epicenter : Cruseilles near Annecy,
about 100 km from GrenobleMagnitude : 4.5/Richter
P-wave S-wave
time delay of S-wave Δt=15s→ distance from source ~ 90 km
dpp (μm)106
65
84
70
70
Slide: 21ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationEarthquakes
Date: 26/12/2005Time: 07:58:50 (local time)
01:11:50 (at ESRF)Magnitude: 8.9Epicentre: west coast of Northern SumatraDistance: ~ 11000 km (surf)~ 9100 km, v ~11.7 km/s
Date: 03/12/2000Time: 05:24:00 (local time)Magnitude: 2.3Epicentre: Domène, Francedistance: 15 ~ 20 km
Distance effects !!
Slide: 22ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationTraffic generated vibration
Main contribution in the vibration noise (period of 24H, week)
Road traffic with an 26-T truck, Feb 1993
0
1
2
3
4
5
0 20 40 60 80 100
distance from road - lane (m)
d pp
(μm
) Av. Martyrs S-->G
Av. Martyrs G-->S
motorway A480
Distance effects― at least 30 m necessary to have
limited effects on the ESRF site
Slide: 23ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationTramway Line-C extension(Vibrations influences)
1st vibration studies made by ESRF― In 1993, UJF campus, SMH― In 1999, Fontaine
Vibration concerns expressed by ESRF and CNRS to Authorities (Prefecture, Mairie, DDE)Coordinated studies and meetings―Territoire 38―Acouplus―VibraTec― ESRF, CNRS, CEA
Study made by VibraTec in 2008
Slide: 24ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationTramway Line-C extensionVibration study
Vibration sources (generated by tramway, measured at 3 m from rail)Vibration propagation and attenuation in the soilVibration transmission to the ESRF buildings (EXPH)
Slide: 25ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Ground vibrationTramway Line-C extensionResults of vibration study
Source : tramway Citadis on recent railAttenuation rate: ~ 0.25 dB/mDistance between future Line-C rail to ESRF central building: 180 mEstimated vibrations level due to future tramway < actual ground vibration level at the ESRF siteEfforts requested so that the Tramway line-C should not generate higher vibrations than existing ones !
Slide: 26ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Simple model MKCMass: mStiffness of the spring: kDamping constant: c (=2γm)Resonant frequency:
Transfer function
Vibration of mechanical structure
Mass Spring Damper system(1 DOF system)
mkf
ππω
21
20
0 ==
xg
020
2 **21
ωωγωω jXXFrF
g +−==
10-1 100 10110-2
10-1
100
101
102
Normalised frquency f/f0
Am
plitu
de
response function of a MKC model
gama=0.03gama=0.1gama=0.2
10-1 100 101
-150
-100
-50
0
Normalised frquency f/f0
phas
e (d
egre
e)response function of a MKC model
gama=0.03gama=0.1gama=0.2
Slide: 27ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
ESRF magnet-girder assembly MGAs
1st mode : lateral rocking due to the deformation of 3 jacks. A global mode
Vibration of mechanical structure
Complex system(Multi DOF system)
Slide: 28ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Passive damping systemsWidely used, effective, cheapDamping Plate, Damping PadDamping LinkTuned Vibration Absorbers (TVA)
Active damping systemsSome commercial products - active vibration ISOLATION system:― TMC stacis (PEL)― Halcyonics (OML, ID10, SSL)― HWL Sc. Instr.
Acoustic noise reduction deviceCould be expensiveDesign specificActuator - sensor limitation
Vibration of mechanical structure
Vibration Damping
Slide: 29ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
High performance in vibrationInsufficient stiffness for static positioning
Vibration of mechanical structure
Damping Plates for MGA
2mm thicksteel plate
0.5mm thinsteel plate0.18mm VEM
cross section (not in scale)
Slide: 30ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Increase stiffness and f0Damping factor > 8
Vibration of mechanical structure
Damping links for MGA
GMF :Girder Mounting Fixture
FMF :Floor Mounting Fixture
VEM :ViscoElasticMaterial
Slide: 31ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Implemented in 2000Significant e-beam stability improvement
Vibration of mechanical structure
Damping links for MGA(Performance on e-beam)
PSDpk rms4-12Hz
μm2/Hz ratio μm rationoDL 158 11.7
DL 3.2 49 3.1 3.8
Slide: 32ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
1st Tested in 2003, in collaboration with CERN1st Installation at ESRF - PEL in 2007Tested and commissioned in 2008-20 dB (2~40 Hz), -10 dB (1~100 Hz)70 k€ for 3 mounts
Vibration of mechanical structure
Active vibration isolation systems - (TMC Stacis 2100)
10-1 100 101 102-50
-40
-30
-20
-10
0
10
20 PEL STACIS ON - AC OFF - Loaded
Frequency in Hz
FrF
(dB
)
ZXY
Slide: 33ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Used in Optical Metrology LabID10, SSLTest results― Effective damping above 2 Hz― Amplification below 2Hz
~ 7 k€Equivalent: HWL Sc. Instr.
Vibration of mechanical structure
Active vibration isolation systems (Halcyonics)
Floor: 0.2 µmTable: 0.4 µmAFM: 0.7 µm
Slide: 34ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration propagationMechanical (air) acoustic ground(Helicopter flying over Soleil site, 1996)
Doppler Effects :
s
helico
helico
sV
VV
Vff
−=
Δ 1
Vs : sound speed
Δf/f ~ 1/8 Vhelico ~ 42 m/s
~ 151 km/h
Spectrogram of vertical acceleration (dB.µm/s2)
X 10
X 3
Slide: 35ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
e-beam stability
Jul00 Oct00 Jan01 Apr01 Jul01 Oct010
2
4
6
8
10
12
14
dRMS-horizontal (μm) (4-12 Hz)
The RMS amplitude was reduced10 μm to 2.7 μm (4-12 Hz)12 μm to 4 μm (4-200 Hz)
damping links installation
1000≈= −
quadrupole
beamePSD
PSDratio
30≈−
quadrupole
beameRMS
RMS This ratio agrees with theoretical estimation
Slide: 36ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
e-beam stability
In the frequency range of 4-200 HzdRMS-horizontal = 1 μm, (0.25% of horizontal beam size) @ high-β sectiondRMS-vertical = 0.6 μm, (7.5% of vertical beam size) @ low-β section
at the middle of a high-β straight section (βx = 35.4 m)RMS horizontal = 402 μ m
Δ RMS horizontal ( μ m) 4-12 Hz 4-200 Hzno damping links (μm) 10 12with damping links (μm) 2.7 4damping links + feedback (μm) 0.28 1
at the middle of a low-β straight section (βz = 2,5 m)RMS vertical = 8 μ m
Δ RMS vertical ( μ m) 4-12 Hz 4-200 Hzwith damping links (μm) (μm) 0.5 1damping links+feedback (μm) 0.17 0.6
Slide: 37ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
X-ray beam stabilityExample of ID06 Cinel mono
0 20 40 60 80 100104
106
108
1010 ID06 Cinel Mono - Effect of pumps - X-ray PSD
Frequency in Hz
PSD
in a
.u.
All ONP1 OFFP1 and P2 OFF
0 20 40 60 80 1000
0.5
1 ID06 Cinel Mono - Coherence X-ray ~ vibrations
Frequency in Hz
Coh
eren
ce
0 20 40 60 80 100
10-5
100
ID06 Cinel Mono - Correlation X-ray and vibrations
Frequency in Hz
Dis
plac
emen
t (um
), X-
ray
inte
nsity
in a
.u.
VerticalHorizontal YXray intensity
Correlation between X-ray intensity fluctuation and mechanical vibration
F=24.8, 66.2, 70.3, 78.7, 82.8 Hz1st peak due to vacuum pump 1, other 4 peaks due to pump 2
Remaining peaks probably due to mechanics room for improvement
Slide: 38ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
X-ray beam stability
Example of ID20
Many pumps
0 20 40 60 80 10010-10
10-5
100
ID20 - Effect of pumps - X-ray PSD
Frequency in Hz
Dis
plac
emen
t (um
), In
tens
ity in
a.u
.
Mirror2MonoMirror1X-ray
0 20 40 60 80 100106
108
1010
1012 ID20 - Effect of pumps - X-ray PSD - S1=0.02x3
Frequency in Hz
PSD
in a
.u.
P2 OFFP2 ON
Slide: 39ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsVibration on the EXPH floor
Various measurements show vibration increases on the EXPH floor
A vibration survey campaign on all the EXPH floor carried out during summer 2009
4 geophones (vertical, L4C) placed along each beamline (ID or BM)Measurements period: June-30 to July-21, working time
8:00
10:00
12:00
14:00
16:00
18:00
0 5 10 15 20 25 30 35ID/BM #
time m
eas (
hh:m
m)
Slide: 40ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsResults of the vibration on the EXPH floor, in 2009
Slide: 41ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsPictures of the vibration on the EXPH floor, in 2009
DPP
X
Y
0.356
0.453
0.551
0.648
0.746
0.843
Integrated Amp 1st peak
X
Y42.100
51.871
61.643
71.414
81.186
90.957
Integrated Amp 2nd peak
X
Y
0.862
2.101
3.341
4.581
5.821
7.061
Integrated Amp 3rd peak
X
Y
0.298
1.840
3.383
4.925
6.467
8.009
dpp (μm)(1-100 Hz)
dRMS-Δf=2Hz (nm)(1-20 Hz)
dRMS-Δf=2Hz (nm)(20-40 Hz)
dRMS-Δf=2Hz (nm)(40-60 Hz)
Slide: 42ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsPicture of the vibration on the EXPH floor, in 2009
Beamline number - IDxx/BMxx
Freq
uenc
y in
Hz
EXPH floor vibration - acceleration spectrogram (2009)
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 320
10
20
30
40
50
60
70
80
90
100
Slide: 43ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsVibration on the EXPH floor
Vibration increased during last 10 years:
Wide bandHigh frequenciesMany peaks
Internal vibration noisesProposal to remedy the situation:
Sources identificationProposition and correctionCollaboration of all staff to limit vibration generation
Set up a procedure to check some new installations in terms of vibration ?
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
Frequency (Hz)
PSD
(µm
2 /Hz)
EXPH ID26 - Vertical PSD, 2009
Floor 1Floor 2Floor 3Floor 4
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
Frequency (Hz)
PSD
(µm
2 /Hz)
EXPH ID26 - Vertical PSD, 2009
in 1998
Floor 1Floor 2Floor 3Floor 4
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
Frequency (Hz)
PSD
(µm
2 /Hz)
EXPH BM20 - Vertical PSD, 2009
Floor 1Floor 2Floor 3Floor 4
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
Frequency (Hz)
PSD
(µm
2 /Hz)
EXPH BM20 - Vertical PSD, 2009
Floor 1Floor 2Floor 3Floor 4in 1999
Slide: 44ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsCooling flow induced vibrations
Commonly used cooling fluids at ESRF:WaterLiquid nitrogenGas (Helium, nitrogen, air)
Vibration due to cooling flowIncrease with flow rateFlexible tube, corrugated tube
Cooling flow optimizationDecrease vibrationsSave pumping capacity (no need to add additional capacity in EX2)Define and regulate necessary flow rate for each componentsCombine serial and parallel connections
Velocity or Re(flow rate)
cooling coef. hcv
LaminarTransition
Turbulent
pressure drop ΔP
Slide: 45ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsCooling flow induced vibrations
ExamplesMachine magnet-girder MGAID24 mirrors
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
G30 CELL 14 - PSD in horizontal Y direction, no Flow
Frequency in Hz
PSD
in μ
m2 /H
z
FloorGirderQuad centreQuad downstream
0 20 40 60 80 10010-10
10-8
10-6
10-4
10-2
G30 CELL 14 - PSD in horizontal Y direction, with Flow
Frequency in Hz
PSD
in μ
m2 /H
z
FloorGirderQuad centreQuad downstream
10 20 30 40 50 60 70 80 90 10010
-10
10-8
10-6
10-4
10-2
frequency (Hz)
PSD
(µ2 /H
z)
Average transverse PSD of floor, Mirrors in ID24
ID24-FlhyID24-M1hyID24-M2hy
Slide: 46ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsCooling flow induced vibrations1st measurement results (ID24 mirror)
Natural frequencies: 376, 710 HzWater flow in corrugated tube excites the resonant frequencies of the piping systemFlow rate, dtube, f dper =5~ 10 mm
0 20 40 60 80 100Time in sec - (flow rate varied)
0
100
200
300
400
500
600
700
Acceleration in μm/sec2
Freq
uenc
y in
Hz
(0 l/min) (5 l/min) 0.5 l/min4 l/min
dper
710 Hz
376 Hz
Slide: 47ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Vibration investigationsCooling flow induced vibrations1st measurement results (ID24 mirror)
The 2 peaks at f=376, 710 HzVery high accelerationBut also spectral displacement comparable to the peak at 3 Hz
L/min
Slide: 48ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Summary and perspectivesSome points on vibration at ESRF
Ground vibration levelSlight degradation of stability on the EXPH floorX-ray beam vibration stability (>1Hz) can be seriously impacted by internal vibration sources
Proposals:Investigation to identify vibration sources in EXPH1Investigation on cooling flow induced vibrationProposition for improvementsCall for collaboration of all staff to limit vibrationsImprove awareness of vibration aspects
QuestionsShall we set up a procedure to check new installations in terms of vibration ?Can we reinforce dynamic analysis capability to assist and improve design of new systems?
Improve stability ☺ ☺
Resources
Slide: 49ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Acknowledgement
Many thanks to
Trainee students: Alice Lan, Renaud FineFIV-WG: Y. Dabin, T. Mairs, L. Petit
And many colleagues inISDD (ME, Optics,…)EXPD (ID06, ID20, ID24,…)ASD (FE group, L. Farvacque, E. Plouvier,…)BIG
Slide: 50ISDD Friday lecture: Vibration & mechanical stability / L. Zhang, 9-April-2010
Thank you for your attention !
ISDD Friday Lecture, 9 April 2010