Acoustic CAE in Japan（Automotive)Masatake Saitoh / Free Field Technologies Japan

Table of Contents

3

ACTRAN OVERVIEW

FREQUENCY DOMAIN AND TIME DOMAIN.

CO-SIMULATION

ACOUSTIC APPLICATION

ACTRAN Overview

Actran Overview

Frequency Domain andTime Domain

Frequency Domain and Time Domain

• Actran：Aciustic CAE

• Vibro-Acoustic

• Aero-Acoustic

• Frequency Domain

is usual.

• Japanese customers

are interested in time

domain analysis.

Co-Simuration

Example: Co-Simulation(Gear Noise)

MBD & FEA

coupled simulationsMBD Results Acoustic Analysis

Rigid parts Motion Create MNF (powered

by MSC Nastran) …

Export Flex parts vibrations in OP2 file format

Acoustic analysis set-up Time-domain acoustic radiation Post processing:

• Acoustic maps, animations• Audio files• Frequency domain post-processin

g

Adams User Interface Actran VI

Example: Co-Simulation(Impact Sound for Golf Club)

• Adams• Model

• Head: Flexible `Part

• Shaft：Discrete Flexible Link

• Contact: Impact Function

• Analysis

• Total Time：0.5Sec

• Time Step ：5e-5Sec

Flex(MNF)

DiscreteFlexibleLink

Adams Model

Example: Co-Simulation(Impact Sound for Golf Club)

• Actran• Analysis

• Total Time：0.5Sec

• Time Step ：5e-5Sec

• Post Processing

• Subjective Evaluation

• WAVE File for results

• Sound Quality

• Objectivity evaluation

• 3D Map(Time vs Frequency vs

SPL)

Example: Co-Simulation(Sloshing Noise)

• What: Native interface with MSC Dytran (explicit solver for dynamic analysis, including FSI) time for performing acoustic radiation with Actran

• Targets: Fuel tank sloshing noise, hydraulic pipe noise, impact noise and others

• Key Benefit: Actran can read directly native MSC Dytran results in THS format

SAE 2015 World Congress & Exhibition, Complete Multi-Discipline Simulation for SloshingNoise. Douglas Marriott, Takeshi Ohtomo, Tohru Wako

Acoustic Applications

Actran User in Japan

• Total 130

Actran User in Japan

Auto Auto Supplier

Electric Other Machinery

Aero University/ Research

Radiation Noise(Frequency Response)

Basic Acoustic Application

One way coupling (Vibration is calculated by other CAE tool)

Advantage of Actran

VI Mesher (Hexa Core)

Automatic Model Preparation（for Each Frequency)

Faster Analysis(Green Analysis)

Excellent Post Processing

Current Trend

Detailed Modeling

High Frequency

Electric Device Noise

Radiation Noise from Powertrain

• Good Correlation with Test Results

• High Speed Calculation (Green Analysis)

Test

CAE

Acoustic Radiation with ActranIntake Vibration with Nastran

Design Improvement – SPL Reduction

Radiation from Electric Powertrain

JMAG-Nastran-Actran

Electromagnetic force distribution

Mode Analysis

Acceleration

（JMAG）

（MSC Nastran）

（Actran）

1

2

3

出典：JMAG アプリケーションカタログ20番の事例

Acoustic

MSC Nastran（Mode Analysis）1

Frequency Results

Electromagnetic force Vector

MSC Nastran（Mode Analysis）2

Mode No Frequency Hz

1 1760

2 1770

3 3670

4 4530

5 4790

6 4920

7 5930

1st Mode（1760 Hz）

5th Mode（4790 Hz）

MSC Nastran （Frequency Response）2

1760 Hz

4790 Hz

Actran（Frequency Responce）3

SPL on Microphone1760 Hz 4790 Hz

Duct Noise Analysis

Duct and Silencer Application

Pipe Noise and Shell Noise

Advantage of Actran

VI Mesher (Hexa Core)

Automatic Model Preparation（for Each Frequency)

Modeling of Absorption:

Modeling of Pinching Metal

Temperature and Flow

TMM Analysis (Transfer Matrix Method)

Current Trend

Detailed Modeling

High Frequency

Remark for Vibro-Acoustic

On the complete line:The new advance TMM method is valid

even at high frequency

pressure at 5100Hz

Intake and Exhaust noise analysis

• Exhaust Noise• Pipe noise:：

Flow・Temperature・Absorption

Punching Metal etc

• Shell noise:

Vibro-Acoustic

• Actran can consider• Duct Mode

• Temperature/Flow

• Absorption Punching Metal, …

• Strong Coupling with Vibration

• TMM

• Integration with 1D Tool

• Vehicle Design

エアークリナー内　マイク1

0

20

40

60

80

100

120

0 500 1000 1500

周波数（ｈｚ）

SPL(ｄB

)

simulation modified micro 1inside [SPL] SPL (in A/C 1)

Car Outside Noise Analysis

• Engine Noise

• Exhaust Noise

• Wind Noise

Exhaust noise

Input force from Engine

Booming n

oise

Sound quality

Frequency [Hz]En

gin

e r

evo

luti

on

s p

er

min

ute

[rp

m]

Transfer function for air-borne noise

Transfer function for structure-borne noise

Trim(Absorption) Analysis

Most Important Technology for Noise Reduction

Advantage of Actran

BIOT Model (UP: Detail setting)

BIOT Model (MIKI: Simple setting)

Impedance(without BIOT parameter)

Optimization of Parameters

Current Trend

Detailed Modeling

High Frequency

Remark for Vibro-Acoustic

Trim Analysis Validation

Trimmed Body Analysis

W/o insulator

W/ insulator

Acoustic transfer function

Structure transfer function

Experiment

W/o insulator

W/ insulator

Acoustic transfer function

Structure transfer function

Dash insulator and floor carpet

Simulation

Rode Noise Analysis

• Two noise source are considered

• Structural Born Noise （Dynamic Load)

• Air Born Noise（DSF)

TL( Transmission Loss) Analysis

Most Important Technology for Noise Reduction

Advantage of Actran

DSF( Diffuse Sound Fields ) Boundary Condition

BIOT Model

Structural Born and Air Born

Current Trend

Experiment to CAE

TL Analysis(Glass with Rubber)

TL Champ Diffus

15

20

25

30

35

40

45

50

100 1000 10000

Frequency (Hz)

TL

(d

B)

Coulisse B9 P3 Initiale

Coulisse B9 P3 Géométrie n°1

Coulisse B9 P3 Géométrie n°2

Coulisse B9 P3 Géométrie n°3

Épaisseur de vitrage de 3,85 mm

Vibro-acoustic model

glass run c

hannel glass

air (I-FEM)

Non-Linear FE

Acoustic Analysis

Aero-Acoustic Analysis

Noise based on Aero-Dynamics

Integration with CFD tool

Advantage of Actran

Realistic Noise Source(Lighthill source/Mohring Source/Surface Pressure)

Many Experiences (Since 1998)

Filtering Technique for High Wave Number Source(Acoustic Perturbation Equation/Wave Number Decomposition /Pelliculer Decomposition)

Current Trend

Increase of the Demand

Aero-Vibro-Acoustic

Wind Noise

Wind Noise with the SNGR Method

Challenge

Turbulences due to the wind flow around the car produce noise that can propagate inside the cabin. For pre-designing efficiently aerodynamic components it is necessary to speed the simulation process.

MSC Solutions

Actran is used to perform aeroacoustics computations with the SNGR method and Lightill sources. The pressure on the window coming from acoustic phenomenon hasbeen retrieved thanks to the wave numberanalysis.

Value

The SNGR method in Actran is validated by Mitsubishi motors. It uses only a steadyRANS CFD: it opens the door to predict efficiently the impact of an aerodynamic design on the acoustic transparency of windows.

Aerodynamic noise at 100km/h, 500Hzpressure 5dB lower on the rear wheel than on the front wheel

5m

microphone

Simulation vs. measurement

FFT Acoustic Simulation Conference 2014, Fumihiko Kosaka, MITSUBISHI MOTORS CORPORATION

Speaker Analysis

Most Popular Sound Analysis

Advantage of Actran

Coupling and Non-Coupling Analysis

Frequency Domain and Time Domain

Excellent Post Processing

Current Trend

Detailed Modeling

High Frequency

Sound Quality

Car Audio Speaker

PhysicalLoudspeaker & Acoustic

ModalCar door structure

Excitation Loudspe

aker configuration with T&S parameters

BEGIN MATERIAL 1VOICE_COILFORCE_FACTOR { 5.45, 0}ELECTRICAL_INDUCTANCE 0.00025ELECTRICAL_RESISTANCE { 2.6, 0}

END MATERIAL 1

Loudspeaker Equivalent Electric Circuit

Car inner cavity with/without acoustic treatment

• Volume 2.95m³

•𝐿

𝜆≈ 80

• Two Nvidia Tesla K80

• Frequency 15 kHz

• DOF 383 Million

• Computation time 4h00

Untreated Treated

Velocity BC / Loudspeaker

Impedance BC

Time Domain Analysis

Considering Non-Linear Phenomena

One way coupling and Vibro-Acoustic Coupling

Advantage of Actran

Stable for Large Scale Model

Sound Quality

Integration with Adams, Marc, Sol700,Dytran

Current Trend

Non-Linear Phenomena

Real Sound

Sound Quality

Switch Sound

• Adams,Marc,Sol700

• Evaluation of Sound Quality

Door Closing Sound

• Adams-Marc-Actran Co-Simulation

Time Domain Analysis(DGM)

Very Large Scale Acoustic Analysis(Ex. 1Billoin DOF)

Time Domain Analysis (Frequency response using Post Processing）

Advantage of Actran

New Methodology（Discontinuous Galerkin Method)

(Max) 16th Element Order

・Integration with Adams, Marc, Sol700,Dytran Sound Quality

Current Trend

High Frequency(Supersonic Wave Field)

Car Parking Sensor, Ultra Sound 50 kHz

• Two Nvidia Tesla K80• Frequency 50 kHz• DOF 984 Million• Simulation time14h40

• Volume 0.1 m³

•𝐿

𝜆≈ 135

Actran:Integration with many CAE tools

Acoustic

MBDLinear

Non-Linear

Pre/Post

SOL700

Aero Acoustic

Sound from Non-Linear FE

Sound from Non-Linear FE

Electro Magnetic

Pre/PostSound from Electro

Magnetic

Sound from Linear FE

Sound from MBD

Thank you