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Transcript of Dirk von Werne, Siemens PLM Software Predicting structure borne tonality · PDF...
Restricted © Siemens AG 2014 All rights reserved. Smarter decisions, better products.
Predicting structure borne tonality
contributions – a hybrid test-
simulation method
Dirk von Werne, Siemens PLM Software
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 2 Siemens PLM Software
Overview
Background-Tonality
Transfer Path Analysis – Principle
Field Testing
Test-based Analysis and Troubleshooting
Test-Simulation Hybrid Process
Simulation Results from Validated FE Model
Use of Validated Model: Mitigation of Tonality
Outlook – Towards a Fully Virtual Prediction
Conclusions
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 3 Siemens PLM Software
Summary
Structure borne tonality noise from gearbox or generator:
Challenging to diagnose and mitigate on system level.
Transfer paths and noise radiating panels difficult to confirm
Test-Simulation hybrid process:
Good ability to confirm Transfer paths and noise radiating panels
Operational and transfer testing:
Data for model validation
Excitation for simulation process
Insight in fundamental phenomena
Simulation with validated vibro-acoustic model:
Structural model loaded with equivalent excitation from test
Vibration response forms the boundary condition for noise radiation.
Model can be exploited for
detailed operational deflection shapes
transfer paths and acoustic panel contributions
Design modifications can be applied in the virtual world first to check their effectiveness.
.
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 4 Siemens PLM Software
Background
Tonality
From gearbox or generator
input
Airborne or structure borne –
structure borne typically at
lower frequencies
Often a matter of system
integration
‘Good’ gearbox plus ‘good’
turbine not necessary free of
tonality0
10
20
30
40
50
60
70
80
1 10 100 1000 10000 Frequency (Hz)
So
un
d P
ressu
re L
evel (d
B)
138.8dB 105.0dB
133.3dB 104.6dBA
132.5dB 103.3dBA
135.7dB 101.4dBA
135.0dB 101.8dBA
Lw LwA (unweighted)
L5
1525kW
L4
802kW
L3
600kW
L2
415kW
L1282kW
SOUND POWER LEVEL
AERO
1fz2
2fz2
1fz3
3fz1
4fz1
2fz3
LOW FREQUENCY
20-200Hz
MEDIUM FREQUENCY
200Hz-2kHz
HIGH FREQUENCY
2-20kHz
INFRASOUND
(inaudible or subsonic)
LOW FREQUENCY
20-200Hz
MEDIUM FREQUENCY
200Hz-2kHz
HIGH FREQUENCY
2-20kHz
INFRASOUND
(inaudible or subsonic)
SOME 1.5 UNITS SHOW UNACCEPTABLE LOW & MID FREQUENCY AUDIBLE TONALITY
10dB
2014-10-17
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Page 5 Siemens PLM Software
Test
Simulation
Transfer Path Analysis, principles
Goal: System Characterization,
Identification of contributions.
Breaking down noise and vibration phenomena into source-transfer-receiver
System characteristics
- structural
- acoustic
Operating loads
- structural
- acoustic
= x
Receiver Transfer path Source
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 6 Siemens PLM Software
Transfer Path Analysis:
Force identification
Transfer Path Analysis on Wind-turbine
•Operational measurements at rotor & gearbox
•FRF measurements & force identification
•FRF=Frequency Response Function
=Transfer Function
•Forward prediction to far-field
Farfield noise
Rotor
Tower
Gearbox
F1
x4
x3
T14
T13
F2T24
T23
224114214
223113213
..,
..,
FTFTFFfx
FTFTFFfx
2
1
2414
2313
4
3
F
F
TT
TT
x
x
4
3
1
2414
2313
2
1
x
x
TT
TT
F
F
F : Excitation
X : Response
T : Transfer Function
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 7 Siemens PLM Software
OPERATIONAL DATA TESTING
Measure up to 400 data points
Steady state or run-up
TARGETS
Measure Transfer functions
Derive input dynamic forces
Measure all necessary vibration responses
including system transmission and radiating
panels
Measure all necessary acoustic responses:
cavity internal, external acoustic pressure
and far field response
> Provide input, output responses and all
intermediate transfer function data to
validated FE model
THE UNIT
Analysis of Wind Turbine TonalityField testing
2014-10-17
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Page 8 Siemens PLM Software
Test setup scheme
Microphones
(Far Field)
LMS Scadas mobile
Nacelle
LMS Scadas mobileIn Rotor
Hub
IRIG-B GPS receiver
Bottom of Tower
LMS Scadas III
LAN cable
LAN connection
through slip ring
Includes input
from wind turbine
operation:
Torque, current,
pitch angle, yaw
angle, etc.
simultaneously
tracked
2014-10-17
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Page 9 Siemens PLM Software
Test Based Analysis and Troubleshooting
Powerful diagnosis tool, e.g. Operational Deflection Shape (ODS)
In a hybrid Test-Simulation process, the missing contribution information can be
retrieved from simulation.
Also Transfer Path analysis, mount
isolation, averaged spectra by component,
modal analysis, ….
But:
No reliable information about noise
radiating surfaces
Difficult to identify transfer paths over
large bearings and other line connections
– typically no opportunity to disconnect
components
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 10 Siemens PLM Software
Analysis of Wind Turbine Tonality
Hybrid Process
FE Modeling
Assembly
Updating
Model
Assembly/Reduction
Component Model
Building
Component Models
Wrapping/
acoustic Modeling
Assembly Models
Component
Updating
FE Modeling
Experimental
Modal Analysis
Experimental
Modal Analysis
Acoustic response
Acoustic Analysis
Validated FE model
Loads (Test – CAE)
SimulationTest
2014-10-17
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Page 11 Siemens PLM Software
ACOUSTIC
RADIATION ATV
X
SURFACE VIBRATION VELOCITY
ATV acoustic transfer vectors
FE structural model BC [m/s]
=
ACOUSTIC RESPONSE
Sound Pressure Level
ATV BASED RESPONSES ALLOWED TO PERFORM DESIGN ITERATIONS
Analysis of Wind Turbine Tonality
Validated model responses
Ranking of Radiation Components
2014-10-17
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Page 12 Siemens PLM Software
Use of Validated Model: Mitigation of Tonality
Exploit validated model for
• Contribution analysis
• Concept modifications
• Parameter studies
• Detailed design modifications
Reduced model for fast concept modifications
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 13 Siemens PLM Software
Outlook – Towards a Fully Virtual Prediction
Can we use upfront simulation without involving test data?
Find big issues, identify phenomena => possible now
Vibro-acoustic transfer functions to identify system sensitivity for drivetrain matching
to support gearbox/generator requirements => possible in short term
Accurate prediction of noise and tonality => some more work required
:
2014-10-17
Restricted © Siemens AG 2014 All rights reserved.
Page 14 Siemens PLM Software
Conclusions
Putting together the strengths of testing and simulation methods, a hybrid
process to diagnose wind turbine tonality has been developed and demonstrated
Test giving insight in global phenomena, providing operational deflections, forces
and transfers
Model validation
Simulation providing detailed deflection shapes, radiation contributions
Fast iteration of concept and design modifications