Virtual NVHProcess with

ADAMS/VibrationGabriele Ferrarotti

Sr. Industry Manager2001 MDI Japan Users

Conference

Agenda

Two approaches for system-levelTwo approaches for system-levelvibration analysisvibration analysisIntegrating vibration investigation inthe development processAccessing continuous productdevelopment

Tacoma Narrows Bridge

New Tacoma Narrows Bridge

The Virtual NVH Process

Slower; higher fidelity

Inputs to Mechanical

Model

Post-processingADAMS solution

Time Domain; Physical Space;Fully nonlinear

Time DomainInputs

Plots, animations, & tables and

some frequency data within

ADAMS

NVH data processingwithin I-DEAS Test

Frequency DomainInputs

Frequency Domain;Modal Space;

Linear

Faster; approximate

Slower; higher fidelity

Inputs to Mechanical

Model

Post-processingADAMS solution

Time Domain; Physical Space;Fully nonlinear

Time DomainInputs

Plots, animations, & tables and

some frequency data within

ADAMS

NVH data processingwithin I-DEAS Test

The Time Domain Approach

Standard ADAMS product line as virtualprototyping vibration tool

Independent from physical testingSystem-level approach (opposed to FE-likecomponent approach)ADAMS/Solver enables to take into accountnon linearity effectsCPU time increases proportionally with therequired frequency resolution

The Time Domain Approach

Case Study: Ford Motor CompanyBusiness:Business: Major automotive manufacturer

Challenge:Challenge: Estimate radiated block noise (strongcustomer dissatisfier) caused by sidethrust forces

Solution:Solution: FFT of piston side forces from anADAMS detailed model are used asinput for the NVH analysis in the FEtool to predict sound power level andcorrelate it with measurements

Value:Value: Piston slap noise in different engineconfigurations can be virtually predictedearlier in the design process

The Virtual NVH Process

Slower; higher fidelity

Inputs to Mechanical

Model

Post-processingADAMS solution

Time Domain; Physical Space;Fully nonlinear

Time DomainInputs

Plots, animations, & tables and

some frequency data within

ADAMS

NVH data processingwithin I-DEAS Test

Frequency DomainInputs

Frequency Domain;Modal Space;

Linear

Faster; approximate

Inputs to Mechanical

Model

Post-processingADAMS solution

Plots, animations, & tables and

some frequency data within

ADAMS

NVH data processingwithin I-DEAS Test

Frequency DomainInputs

Frequency Domain;Modal Space;

Linear

Faster; approximate

The Frequency Domain Approach

ADAMS/Vibration add-on product asvirtual prototyping vibration tool

Allows to take your system to differentoperating points to analyze the vibratorybehavior (without having to create newmodels!)Allows various evaluations in modal space,including forced response in the frequencydomain, FRF and mode shape analysis,modal participation factorsValidity within the limits imposed bylinearization approach

The Frequency Domain Approach

Case Study: IsuzuBusiness:Business: Major truck manufacturer

Challenge:Challenge: Create vehicle natural frequency map toinvestigate vibration problemsbypassing the expensive, timeconsuming typical experimentalapproach

Solution:Solution: Development of customized ADAMSenvironment able to allow to reviewfrequency data with the help of a webtool

Value:Value: Accurate evaluation of vehiclevibrations over 50Hz helps to shortendevelopment time and to cut cost

Agenda

Two approaches for system-levelvibration analysis

Integrating vibration investigationIntegrating vibration investigationin the development processin the development processAccessing continuous productdevelopment

Controls

Handling

Durability

Virtual Prototype

Integrated NVH inthe Functional digital Prototype

NVH

Packaging

Typical AutomotiveSystem-Level Scenario

Input (to front wheels):In-phase sine sweep0.8 – 40.0 Hz2mm peak-to-peakdisplacement

Measure: acceleration at3DOF on both sides of allengine mounts. Also atselected points on body.

Graph: response vsfrequency, with phase.

Engine-Mount Manufacturer’s Sensitivity Test

Typical AutomotiveSystem-Level Scenario

In modal space withADAMS/Vibration:

Instantaneouscalculation of FRFsbetween any input andany output to quicklyunderstand vehicledynamicsForced vibrationanimationModal contribution mapfor selected inputchannel and frequency

Typical AutomotiveSystem-Level Scenario

Time

Displacement

Time

Frequency

Acceleration

FFT

In physical spacewith ADAMS/Solver:

Input specified intime domain(frequency sweep)Solution intime domain, using∆t = 0.002, tf = 180secOutput in timedomain (accelerationrequests in theengine mounts)

Typical AutomotiveSystem-Level Scenario

ADAMS time domainresults provided to NVHanalyst in TXT - RPCformatCan be imported intoI-DEAS Test from MTS

Typical AutomotiveSystem-Level Scenario

Observations:Harmonics are due to non-linear components in themodel (bushings, mounts,suspension dampers)

Conclusions:“Modal space analysis”with linearized modelprovides fast qualitativeNVH information“Physical space analysis”with complete non-linearmodel provides higherfidelity NVH information

Typical AutomotiveSystem-Level Scenario

Input:Unbalanced masses(leading and lagging) onright wheel (5 g, 2 cm)

Measure:local rotational velocity atsteering wheel

Graph:Frequency responses

Sensitivity study to springstiffness values

Wheel Out Of Balance (OOB) Analysis

Typical AutomotiveSystem-Level Scenario

Investigate thesteering wheelresonance shift dueto change in springstiffnesses

Additional AutomotiveSystem-Level Scenarios

Random Road Profile AnalysisObserve the PSD response of vehiclecomponents to PSD inputs at the contact patch

Powertrain Out Of Balance (OOB) AnalysisObserve the frequency response of vehiclecomponents to out of balance inputs acting onpowertrain components (i.e. driveline vibrationanalysis)

Agenda

Two approaches for system-levelvibration analysisIntegrating vibration investigation inthe development process

Accessing continuous productAccessing continuous productdevelopmentdevelopment

ADAMS/Vibration 11.0 offers:Frequency domain input forcing functionsFrequency response function calculationsModal participation tablesForced vibration animation

The ADAMS/Vibration Solution

Step 1: Create input channels,output channels, and actuators

Splinedefines

PSD

The ADAMS/Vibration Solution

Define inputs/outputs to beused, operating point,

frequency range, and steps

Step 2: Run Analysis

The ADAMS/Vibration Solution

The ADAMS/Vibration Solution

Step 3: PostprocessingSystem ModesFrequency ResponseFunctionsPower SpectralDensityModal ParticipationTablesNormal ModeAnimationForced VibrationAnimation

The ADAMS/Vibration Solution

ADAMS/Vibration 12.0 offers:Integration with vertical products

Same look and functionalities forADAMS/Standalone and ADAMS/VerticalProduct

The ADAMS/Vibration Solution

ADAMS/Vibration 12.0 offers:Integration with ADAMS/Insight

Dedicated dialog box to create objectivemacros for DOE - A/Insight

The ADAMS/Vibration Solution

ADAMS/Vibration 12.0 offers:Modal energy computation

Energy contribution of each model element inHTML format

Conclusions

ADAMS provides two approachesfor system-level vibration analysisallow complete NVH insight early inthe design processADAMS allows to balancecompeting requirements foroptimum NVH by integrating thevibration investigation in thedevelopment processADAMS continuous productdevelopment guarantees a steadilyimproving solution for your NVHprocess