Einführung in die Transferpfadanalyse · (Direct / Mount Stiffness / Matrix Inversion) LMS OPAX...

Unrestricted © Siemens AG 2017 All rights reserved. Realize innovation.

Einführung in die Transferpfadanalyse

Arnd Balger, Siemens Industry Software GmbH, Testing Solutions

2015-11-10

Unrestricted © Siemens AG 2017 All rights reserved.

Siemens PLM Software

Agenda

2 FRF Measurements

1 TPA – Introduction

3 Classical Loads Identification

4 OPA/OPAX, Single-/Multi-Reference and more ….

5 Frequency & Time domain results

6 What-if-Engineering

2015-11-10



Transfer Path AnalysisIntroduction

air-bornestructure-borne

structure-borne

Transferpath analysis quantifies and visualizes the strengths of selected sources and theircontribution via multiple transmission paths to a selected receiver signal (target)

2015-11-10



Transfer Path AnalysisSource-transfer-receiver approach

20.00

80.00

dB Pa2

X =Source (Fi,Qj) Transfer (NTF) Receiver (yk)

yk

structural airborne|| ||

- Operational data required: depending on application - orders, spectra, autopowers, time, …- Transfer data required: FRF / NTF – local indicators and to target

2015-11-10



Accuracy requirementsdepending on objectives

RefinementEngineeringRefinementEngineering

Transfer Path Analysis in vehicle development

DetailedEngineeringDetailedEngineering

UpfrontEngineeringUpfrontEngineering

Test based applications

• Benchmarking

• Target setting

CAE based applications

• Concept Analysis

• Load Identification

• CAE based contributionanalysis

• Hybrid based contributionanalysis

• System engineering

• What-if games andoptimization

• (Fast) Trouble shooting

• Critical component/pathidentification & assessment

• Auralization

• Efficient optimization

Virtual Contribution Analysis

Test Based TPATest Based TPA

2015-11-10



Agenda

2 FRF Measurements


3 Loads Identification




2015-11-10



Transfer Path AnalysisMeasurements of Transfer functions– Removal of source

EngineIntake

Gear

Body

F2’F1

T = F1 x FRF1 + F2’ x FRF2

FRF measurement withoutremoving source

Only valid if

F2’ x FRF2 << F1 x FRF1

EngineIntake

Gear

Body

F2F1

T = F1 x FRF1 + F2 x FRF2

Operational condition

Body

F2 = 0F1

T = F1 x FRF1

Correct method for FRFmeasurement

Removal of sourceFast TPA

2015-11-10



Transfer Path AnalysisMeasurements of Transfer functions– direct or using reciprocity

Impact hammer

Shaker

Miniature Shaker / Integral Shaker

Panel Pressure Exciter

Miniature Volume Source

Mid Frequency Volume Source

Low Frequency Volume Source

Reciprocity

Fj Fk

Xi Xkj

kkj HH

Input at ‘j’, output at ‘k’ isequivalent to input at ‘k’, outputat ‘j’ for structural, acoustic, orvibro-acoustic FRF

2015-11-10



Agenda

2 FRF Measurements






2015-11-10



Transfer Path AnalysisMeasurements - Loads

Direct Measured Direct measured forcesand acoustic strength

Mount Stiffness

Single Path InversionSingle Source –Multiple Indicator

Matrix InversionMultiple Source –Multiple Indicator

LMS OPAXMultiple Source –Limited Indicator

oper

oper

oper

oper

xxx

FxF

xFx

F

1002

1001

1

1

1

1002

1

1001

1

1

1

operm

oper

n

mm

n

opern

oper

x

x

Fx

Fx

Fx

Fx

F

F...

............

...

...1

1

1

1

1

1

1

operm

oper

n

mm

n

opern

oper

p

p

Qp

Qp

Qp

Qp

Q

Q...

............

...

...1

1

1

1

1

1

1

ts XXKF

Structural Acoustic

2015-11-10



Load identification:Direct measured acoustic path, using acceleration orsound intenyity

CcIA

CcPowQ iiii

141422

2ii

shelli XAQ .

iXiA

: normal acceleration of path i (m/s²): surface of patch i (m²)

piston

iX

A1 A2

A3 A4

2015-11-10



Load identification: mount stiffness method

Mount StiffnessEasy and fast methodDisadvantage: accurate mount stiffnessdata seldom available and dependent onload conditions & excitation amplitude

2piai

ii))(a)(a(

*)(K)(F

operational accelerations atboth sides of mount

mountstiffness

||

||

operationalforce

||

Engine

mounts

active side

passive side

IntakeGear

...Fi

Body

api

aai

Ki...

2015-11-10



Load identification: matrix inversion method

)(a

)(a)(a

.

)(H)(H)(H

)(H)(H)(H)(H)(H)(H

)(F

)(F)(F

v

2

11

nvv2v1

2n2212

1n2111

n

2

1

Frequency-by-frequency force identification

Number of indicators (v) must significantly exceed number of forces(n) to minimize ill-conditioning problems (factor 2 as a rule of thumb)

Disadvantage: measurement of full FRF matrix is a huge work

Engine

mounts

active side

a1

passive side

IntakeGear

aq av

ai

...... Fi

Body

Hiq

indicatoraccelerations

FRF matrix

||

||

operationalforces

||

2015-11-10



Load identification:Single path inversion, acoustic example

Nozzle

Indicator Microphones

PHQ PQnozzle.1

Step 1 HPQ

Near Field acoustic-acoustic transferfunctions between nozzle sources andindicators (Pa/m³/s²)

Step 2

Operating pressures in the vicinity ofnozzles (Pa)

Step 3

P1001

P1002

~~~~~~~~~~Qin

2015-11-10



Load identification: OPAX

LMS Test.Lab OPAXReduced parametric load models

(Broadband model)

No or reduced number ofindicators

))(a),(a,parameters(f)(F piaii

Engine

active side

passive side

IntakeGear

...Fi

Body

api

aai

2015-11-10



Transfer Path AnalysisLoad identification methods combined

IntensitedBA

• Direct measured forces

and acoustic strength

• Mount stiffness method

(K. x)

• Nozzle noise

Single source,multiple indicators

• Matrix inversion

Multiple source,Multiple indicators

Note: multiple sets can bedefined in 1 analysis

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Agenda

2 FRF Measurements






2015-11-10



OPA / OTPA methodConcept

=

structural airborne=

px: sound pressure

ax: acceleration

: Transmissibilities estimatedfrom operational measurements

Target

acousticsources

Bodyai

Firewall

IntakeGear

...

=

yk =

Tik

pj=

Tjk

Engine

......

mounts...

Fast methodRequires only operational dataof path references & target(s)No FRFs requiredTransmissibility methodEstimation of transmissibilitiesfrom run-up/down data

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OPA method4 critical elements

1) Cross-coupling between the path references

2) Numerical conditioning errors in the estimation oftransmissibilities from operational run-up/down data

3) Potential errors due to missing paths in the analysis

4) A good total OPA synthesis can not be used as a validationargument

... these limitations may lead to a false identification of significantpaths and prevent the engineer from reaching the right decisionand solving the problem (see ISMA 2008 Conf. paper) ...

2015-11-10



LMS OPAX MethodConcept

p

1jjjk

n

1iiikk Q*NTFF*NTFy

=

structural airborne

=px: sound pressure

ax: acceleration

aix: indicator acceleration

: reciprocal NTF

Fast methodRequires operational data(Active/Passive side of pathreferences, target(s)) & NTFsForce estimation method usingparametric model to reducerequired measurementsSource-transfer-receiverapproach

Target

acousticsources

Body

Firewall

IntakeGear

...

yk =

NTFik

pj=

NTFjk

...

Engine

......

ai1 ai2 ai3=ap

aa

mounts

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Comparison of measurement effort

Conventional TPA(Direct / Mount Stiffness /

Matrix Inversion)

LMS OPAX Response Only O(T)PA

Targets

Active side

Indicators

Targets

Active side

Targets

Passive sidePassive sidePassive side

oper

atio

nald

ata

NTF Direct or Recip Reciprocal

FRF

passive

FRF

indicator

K

mount

loca

lFR

F

almostsameeffort

only 10~15’more

measurementtime after eachOperational run

highesteffort

ORoptional

2015-11-10



Traditional load identificationand improved instrumentation with strain sensors

Traditional instrumentation with accelerometersfor load identification based on• Matrix Inversion• Mount-stiffness• OPAXNew improved instrumentation with strain sensorsfor load identification based on• Matrix Inversion• Direct (calibrated)• OPAX

Accelero-m

eter

Strainsensor

Straingage

Ease of useFreq Range > 2 Hz > 2 Hz Up to DCResponse Global Local LocalS/N ratioSize 10x5mm All sizesTechnology ICP ICP Bridge

2015-11-10



Advanced Load Identification at low frequencybased on Strain Sensors

Vehicle dynamics (handling) 0–2 Hz• Reaction of the vehicle to steering inputs (lateral dynamics), braking (longitudinal

dynamics), …• Constant radius cornering, step steer and release, ISO lane change, constant radius

cornering, sweep input, brake in turn, rollover, …Primary ride 1–5 Hz• the car body moves rigidly on the main springs (bounce, roll, …)Secondary ride 5–15 Hz• Suspension (hop, tramp, fore-aft, …) and powertrain (bounce, roll, …) modes amplify

excitations from road, wheel unbalance, throttle input• Road shake, steering shimmy, impact harshness, tip-in/out, key-on/off, …Vibration comfort 15–50 Hz• Excitations from P/T are amplified by resonances of vehicle body or auxiliaries• Steering shake, floor vibrations, …Acoustic comfort 20–10k Hz• Airborne and structure borne excitation from road, P/T or auxiliaries• P/T boom, gear whine, rolling noise, wind noise, HVAC noise, …

Rid

e&

Han

dlin

gN

VH

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Strain based Path Contribution Results

Time TPA allows detailed investigation of• Force distribution in P/T & suspension connections at each time step• Individual Contributions at a specific moment in time of the transient

Body Loads at one of the Engine Mount connections (X-, Y-, Z-direction) in function of time

Time domain Path Contribution Analysis for Seat vibrations X-direction

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Typical single reference TPA: engine

air-bornestructure-borne

Target: passenger earsPaths: engine mounts, exhaust, intake, drivetrain with mounts, noise emission of surfaces, ..

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Typical multi-reference TPA: Road noise

When: Systems excited by multiple, partiallycorrelated sources

Road-induced noise in a carEngine and air-conditioning noise

Why: No fixed phase relation betweendifferent response DOFs

The interior sound field consists ofmultiple incoherent phenomenaOperational data need to bedecomposed in independent phenomena

(principal components / PCs)Multiple reference signals are neededAnalysis for each independentphenomenon separatelyResults for independent phenomena canbe superposed

Road noise is generated by multiple partiallycorrelated forces acting on the suspension

PCs have no physical meaning

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Multi-References TPA

A. Process Crosspower signals into m sets of referenced virtual spectraB. Quantification of transmission paths for each of this m sets (Consistent phase

relation between spectra in each set)C. Calculate the RMS sum over the m results (Different sets are uncorrelated)

x1 x2 ... xr

x11…x21…xr1

PCA

Forceid.

TPA

x12…x22…xr2 x1m…x2m…xrm

x11…x21…xr1 x12…x22…xr2 x1m…x2m…xrm

f11…f21…fn1 f12…f22…fn2 f1m…f2m…fnm

phenomenon 1 phenomenon 2 phenomenon m

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More methods, e.g. Multi-level TPA

System 1

System 2

Target

System 3

Operational loads

F1

F2

h3,3

h2,3

• From tire through suspension parts• Subframes• …….

2015-11-10



Agenda

2 FRF Measurements






2015-11-10



LMS Test.Lab Transfer Path AnalysisTPA Results

TPA Results: Single Path visualization

TPA Results: Section Comparison

2015-11-10



Vector Contribution

Contribution Analysis – Case by Case RPM or Frequency Contribution Analysis

Contribution Analysis – Path by Path

LMS Test.Lab Transfer Path AnalysisTPA Results – 4D-Display

Spec

trum

:PR

CM

:000

1:S

..

Spec

trum

:PR

CM

:000

2:S

..

Spec

trum

:PR

CM

:000

3:S

..

Spec

trum

:PR

CM

:000

4:S

..

Spec

trum

:PR

CM

:000

5:S

..

Spec

trum

:PR

CM

:000

6:S

..

RM

SSu

m..

10.00

60.00

dB(A

)Pa

Spectrum: PRCM:0001:S

10.00 350.00Hz

Measuredbe_f:18:Xbe_f:18:Z

be_f:5018:Ybe_r:9:Xbe_r:9:Z

be_r:5009:Ysh_f:30:Xsh_f:30:Z

sh_f:5030:Ysh_r:32:Xsh_r:32:Z

sh_r:5032:Ysubf:20:Xsubf:20:Z

subf:5020:Y -40.00

50.00

dB(A

)

Pa

Contribution at case (path or group vs. rpm or frequency) A

10.00 350.00Hz

10.00

60.00

dB(A

)Pa

91.00

Spec

trum

:PR

CM

:000

1:S

..

Spec

trum

:PR

CM

:000

2:S

..

Spec

trum

:PR

CM

:000

3:S

..

Spec

trum

:PR

CM

:000

4:S

..

Spec

trum

:PR

CM

:000

5:S

..

Spec

trum

:PR

CM

:000

6:S

.. RM

SSu

m

Measuredsubf:5020:Xbe_r:5009:Xsubf:5020:Ysubf:5020:Zbe_f:5018:Y

be_r:9:Xbe_r:5009:Ysh_r:5032:X

sh_r:32:Ysh_f:5030:Z -40.00

60.00

dB(A

)

Pa

Contribution at rpm or f requency (path or group vs. case) A

Mea

sure

d..

Tota

l

be_f

:18:

X..

be_f

:18:

Y..

be_f

:18:

Z..

be_f

:501

8:X

..

be_f

:501

8:Y

..

be_f

:501

8:Z

.. be_r

:9:X

..

be_r

:9:Y

.. be_r

:9:Z

..

be_r

:500

9:X

..

be_r

:500

9:Y

..

be_r

:500

9:Z

..

sh_f

:30:

X..

sh_f

:30:

Y..

sh_f

:30:

Z..

sh_f

:503

0:X

..

sh_f

:503

0:Y

..

sh_f

:503

0:Z

..

sh_r

:32:

X..

sh_r

:32:

Y..

sh_r

:32:

Z..

sh_r

:503

2:X

..

sh_r

:503

2:Y

..

sh_r

:503

2:Z

..

subf

:20:

X..

subf

:20:

Y..

subf

:20:

Z..

subf

:502

0:X

..

subf

:502

0:Y

..

subf

:502

0:Z

..

10.00

60.00

dB(A

)Pa

sh_r:32:Z

0.00 350.00Hz

RMS Sum






Spectrum: PRCM:0005:S-40.00

50.00

dB(A

)

Pa

Contribution at path or group (case vs. rpm or frequency) A

Spec

trum

:PR

CM

:000

1:S

..

Spec

trum

:PR

CM

:000

2:S

..

Spec

trum

:PR

CM

:000

3:S

..

Spec

trum

:PR

CM

:000

4:S

..

Spec

trum

:PR

CM

:000

5:S

..

Spec

trum

:PR

CM

:000

6:S

..

RM

SSu

m..

10.0060.00

dB(A

)Pa Spectrum: PRCM:0001:S

0.00 350.00Hz

-40.00

60.00

dB(A

)Pa

99.00

1:1

0.0050.00 Pa 50.00Pa

50.00

Pa

50.00

Pa

be_f:5018:X

be_f :18:Xsubf:5020:X

subf:20:X

sh_f:5030:Y

be_f:5018:Z

be_r:5009:Xbe_f:18:Y

be_r:5009:Y

be_r:5009:Z

Measured

Vector contribution A

2015-11-10



FRF

(1/2)Frequency Domain Analysis extended withTime Domain Analysis

FIR Filter FIR Filter ==

== X

NTF

Freq

uenc

yD

omai

nTP

ATi

me

Dom

ain

TPA

Auralization, Signature Analysis, Sound Quality metrics ...

Indicators(orders, spectra)

Loads (orders,spectra)

Path contributions(orders, spectra)

Indicators (timetraces)

Frequencysourcemodel

Frequencytransfermodel

Loads (timetraces)

Path contributions(time traces)

440.0020.00 HzFSUB:0105:-Y (CH1)

4500.00

900.00

rpm

Tach

o1(T

1)

-10.00

-110.00

dB g

440.0020.00 HzFSUB:0105:+Y (CH1)

4500.00

900.00

rpm

Tach

o1(T

1)

20.00

-80.00

dB N

440.0020.00 HzFRLE:S (CH2)

4500.00

900.00

rpm

Tac

ho1

(T1)

70.00

-30.00

dB Pa

120.000.00 s

0.60

-0.70

Rea

lg

1.00

0.00

Ampl

itude

X

120.000.00 s

24.00

-24.00

Rea

lN

1.00

0.00

Ampl

itude

120.000.00 s

0.10

-0.12

Rea

lPa

1.00

0.00

Ampl

itude

2015-11-10



(2/2)Frequency Domain Analysis extended withTime Domain Analysis

Frequency Domain TPARun-up, run-downStationary road noise…

Operational Data: Spectra, Orders

TPA ModelsMount Stiffness, Matrix Inv., OPAX, …

Component editing Edit Load and NTFs

Auralization Virtual Car/Product Sound

Time Domain TPATransient: speed ramps, pot holes (ridecomfort), engine start-up …Semi-stationary: idle noise, frequencymodulation …Time traces

TPA Models from frequency domain TPA

Component editing Edit Load and NTFs infrequency domain, before calculating timetraces of forces, contributions and overall

Analysissignature, Sound diagnosis, metrics,angle domain …Typical ‘time-structures’ like transients,modulations, ticks,.. are preserved

Auralization Audio replay of individiualtraces (loads, contributions, ..)or reconstructed signal (TPA Synthesis)

:

2015-11-10



Agenda

2 FRF Measurements






2015-11-10



What-if engineering support (1/2)Component Editing

Sourcemodel

Modifiedsourcemodel

Transfermodel

Modifiedtransfermodel

20.00

80.00

dB Pa2

MeasuredTarget

20.00

80.00

dB Pa2Modified

Target

X

X

=

=

Direct Load

Edit Loads & Target FRFs

Mount Stiffness

Edit Target FRFs, Passive / Active sideacceleration, Stiffness

Matrix Inversion

Edit Target FRFs

Make Section Editable to edit Loads

LMS OPAX

Make Section Editable to edit Target FRFs,Operational data (Passive / Active sideacceleration…)

Compared influence of different models ontargets or partial contribution

2015-11-10



What-if engineering support (2/2)Component Editing

Step 1:Select a segment

and apply amodification

Step 2:Observe impact

on PartialContributions and

Total SUM

Step 3:Save modified

model and comparedifferent snapshots

Define differentmodification fordifferent paths

Make Section Editable: Allowcomplex model like Matrix

Inversion to be editable

2015-11-10



TPA Sound Synthesis

Path – Group – TargetTPA Model Structure

On/Off

Gain

Filter

On-line spectra

.

Playlist

2015-11-10


Siemens PLM Software4500.00900.00 rpm

75.00

30.00

dB(A

)P

a

BODY:0001:+XBODY:0001:+YBODY:0001:+ZBODY:0002:+XBODY:0002:+YBODY:0002:+ZBODY:0005:+XBODY:0005:+YBODY:0005:+ZBODY:0103:+XBODY:0103:+YBODY:0103:+ZBODY:0603:+XBODY:0603:+YBODY:0603:+ZFSUB:0101:+XFSUB:0101:+YFSUB:0101:+ZFSUB:0102:+XFSUB:0102:+YFSUB:0102:+ZFSUB:0105:+XFSUB:0105:+YFSUB:0105:+ZFSUB:0601:+XFSUB:0601:+YFSUB:0601:+ZFSUB:0602:+XFSUB:0602:+YFSUB:0602:+ZFSUB:0605:+XFSUB:0605:+YFSUB:0605:+ZTotal

Engine:Anti-roll mountBODY: 0005

Transfer Path Analysis: frequency-domain results:Problem -> path contributions -> path details

TotalDriver Ear

Force

Transfer

Contribution

x

=

Example

2015-11-10



Time Domain TPA:time traces of contribution and forces -> listen & analyze

ENGIN

EContributionEnginemount

ContributionGearboxmount

ContributionAnti-rollmount

TotalDriver Ear

Example

2015-11-10



TPA Synthesis:modified time domain TPA model -> listen & analyze

ENGIN

E

TotalDriver Ear Filtered

contributionof Anti-rollmount

Example

Einführung in die Transferpfadanalyse · (Direct / Mount Stiffness / Matrix Inversion) LMS OPAX...

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Transcript of Einführung in die Transferpfadanalyse · (Direct / Mount Stiffness / Matrix Inversion) LMS OPAX...