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02.07.2014
7th European ATC, Munich June 24th – 26th, 2014
Integrated AVL EXCITE - OptiStruct Software Solution Platform for NVH and Acoustics Bernhard Loibnegger AVL List GmbH Hans-List-Platz 1, 8042 Graz, Austria [email protected]
2 7th European ATC, Munich, June 24th – 26th, 2014
AVL EXCITE
AVL EXCITE INTRODUCTION
AVL EXCITE is a multi-body dynamic software tool, calculating transient in time domain.
Bodies can be: Rigid large systems, short analysis time
Flexible consider body deformation and calculate component
stresses
AVL EXCITE initially was developed for acoustic analysis in high frequency domain.
Therefore it has the following important and basic characteristics:
Consider large number of condensed DOFs (several thousands) per body with
feasible analysis time
Detailed EHD contact representation including local deformation.
AVL EXCITE covers all important excitation mechanisms in the drive line system with
high accuracy, including crank train, valve train, chain and belt drives, gear trains and
piston secondary motion
This is ensured by various specific and advanced non-linear connectors (joints).
3 7th European ATC, Munich, June 24th – 26th, 2014
AVL EXCITE INTRODUCTION
AVL EXCITE covers the dynamic behaviour of the power unit, the
transmission and the entire drive line including vehicle integration.
AVL EXCITE works on system and sub-system level.
AVL EXCITE has 3 main application fields:
NVH from system dynamics to acoustics
(structure and air borne noise)
EHD contact investigations (bearing evaluation, failure mechanisms and friction)
Durability and Strength of components
4 7th European ATC, Munich, June 24th – 26th, 2014
Integrated AVL EXCITE - OptiStruct Software Solution Platform for NVH and Acoustics
From CAD to Air Borne Noise
EXCITE Acoustics
EXCITE
OptiStruct
SimLab, OptiStruct
5 7th European ATC, Munich, June 24th – 26th, 2014
Workflow for Structure Borne Noise
Generation
of Meshes &
Condensation
HyperMesh
SimLab
OptiStruct
6 7th European ATC, Munich, June 24th – 26th, 2014
Model Preparation & Condensation Tools: HyperMesh, SimLab and OptiStruct
OptiStruct for condensation
provides ease-of-use interface to output EXCITE body property files (.OUT2, .OUT4)
PARAM, EXCOUT
SimLab provides special plugins fulfilling
EXCITE mesh requirements
inserting RBE2/RBE3 couplings at journal/pin center nodes
defining retained nodes at predefined areas (e.g. bearings, liner, cylinder head, etc.)
OptiStruct 13.0 will output (.exb) directly (FIRST FE Code!)
PARAM, EXCEXB
OptiStruct 13.0 will generate the inertia invariants for flexible bodies, which perform a global motion
7 7th European ATC, Munich, June 24th – 26th, 2014
Workflow for Structure Borne Noise
Generation
of Meshes &
Condensation
HyperMesh
SimLab
OptiStruct
Creation of
EXCITE
Model
Run
EXCITE
Simulation
8 7th European ATC, Munich, June 24th – 26th, 2014
Creation of EXCITE Model Tool: AWS
Setup EXCITE Model
define bodies
define joints (non-linear)
assign external forces
perform kinetic model check
define load cases
speed sweep
run-up
Run EXCITE Simulation
define simulation control parameters
submit jobs using job management system
support of LSF, PBS Pro, etc.
9 7th European ATC, Munich, June 24th – 26th, 2014
Workflow for Structure Borne Noise
Generation
of Meshes &
Condensation
HyperMesh
SimLab
OptiStruct
Creation of
EXCITE
Model
Run
EXCITE
Simulation
Data
Recovery
OptiStruct
10 7th European ATC, Munich, June 24th – 26th, 2014
Data Recovery Tool: OptiStruct, EXCITE FE Interface
Data Recovery using OptiStruct
EXCITE generates .INP4 file containing either motion quantities for selected time steps or complex displacements for selected frequency steps
All that is required in OptiStruct :
assign .INP4 file and HyperWorks .h3d file (super element matrices) to the analysis
define subcases (modal or transient frequency response)
request output
Store results in Nastran .op2 file
No DMAP, scripts or macros are required
ASSIGN,H3DDMI,AX,name.h3d
ASSIGN,EXCINP,10,model.INP4
VELOCITY = ALL
SUBCASE 10
LABEL = FREQUENCY RESPONSE
METHOD = 10103
DLOAD = 10111
FREQUENCY = 10122
11 7th European ATC, Munich, June 24th – 26th, 2014
Workflow for Structure Borne Noise
Generation
of Meshes &
Condensation
HyperMesh
SimLab
OptiStruct
Creation of
EXCITE
Model
Run
EXCITE
Simulation
Data
Recovery
OptiStruct
Structure
Borne Noise
Post-
Processing
12 7th European ATC, Munich, June 24th – 26th, 2014
Structure Borne Noise Post-Processing Tool: IMPRESS Chart / 3D, HyperView
Special Structure Borne Noise EXCITE Evaluation Tool
Generation of surface velocity levels
Surface normal levels
Maximum levels
3D color plot for 1/3 octave, octave bands, single frequencies or user defined frequency range
Integral levels of structure parts (selection by material / element property or direct)
Integral levels of structure parts versus engine speed or any other parameter
Integral Surface Normal Levels
Oil Pan
Inte
grs
al L
eve
l [d
B]
630 800 1000 1250 1600 20001/3 Octave Centre Frequency [Hz]
EHD2
NONL
10 dB
13 7th European ATC, Munich, June 24th – 26th, 2014
Structure Borne Noise Validation
Target Correlation: +/- 3dB
Measurement
Simulation
14 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Sound Radiation Analysis Workflow
Generation
of Acoustic
WBT Mesh
15 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Automated Generation of the Acoustic Mesh
Interactive 3D viewer for control and optional adjustment of results of each meshing step
Model Preparation within Minutes
Starts from unmodified FE mesh used for the calculation of structural vibrations
3D visualization of the stepwise acoustic mesh generation:
3 – detection of inside / outside acoustic mesh elements
1 – based on predefined layer distances a regular mesh of the complete domain is set up
Step 1
Patent-pending meshing procedure
2 – refinement of elements which intersect the structure skin
Step 2 + 3
4 – all outside elements are merged to reduce the number of elements of the final WBT acoustic mesh
Step 4 – final acoustic WBT mesh (blue) and inside elements (red)
16 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Sound Radiation Analysis Workflow
Generation
of Acoustic
WBT Mesh
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
17 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Field Point Meshes for Result Evaluation
Two Options to Define Field Point Meshes
1 - import of arbitrary predefined meshes (FE format)
2 - use of the integrated field point mesh generator
supported types: sphere and plane
Results with v2014: sound pressure levels in dB or dB(A,B,C)
single frequencies
third octave /octave bands
average / overall levels
18 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Sound Radiation Analysis Workflow
Generation
of Acoustic
WBT Mesh
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
Boundary
Conditions
and Settings
19 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Boundary Conditions and Simulation Settings
Simulation Control
Basic settings:
frequency type (single, range or from imported BC), fluid properties, microphone positions etc.
simulation task: check data, sound radiation calculation, result creation
Type and amount of results to be evaluated: 2D/3D, average/overall, 3rd octave or/and octave bands
Microphone positions – default or user defined
Boundary conditions:
import of structural surface velocities and mapping to Multi Local Velocities boundary condition
Structural surface velocities
optional pressure, velocity or impedance BC (const. or freq. dependent) on selections of the acoustic mesh (MLV surfaces)
Boundary conditions on selections
20 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Dynamic and Fully Automated Velocity Mapping Procedure
Multi Local Velocity (MLV) Mapping
Mapping – transfer of vibrations from FE Mesh to Gauss Points on closest acoustic mesh surfaces (MLV surfaces)
Number of Gauss Points depends on:
frequency
size of the MLV surface
kind of boundary condition
Indirect Distance Weighting (IDW) method:
resultant complex vector at Gauss Points is a linear combination of the 4 closest FE nodes
Benefit
Due to fine Gauss Point distributions local effects are considered even with rough acoustic meshes
Example: surface velocity amplitudes at 806Hz on structure surface (left) and MLV surfaces (right)
MLV surfaces
Gauss Points on a MLV surface
21 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics Sound Radiation Analysis Workflow
Generation
of Acoustic
WBT Mesh
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
Generation
of Acoustic
WBT Mesh
Creation of
Field Point
Meshes
Check Data
Sound
Radiation
Create
Results
Simulation
Run
2D/3D Post-
processing
Boundary
Conditions
and Settings
Boundary
Conditions
and Settings
22 7th European ATC, Munich, June 24th – 26th, 2014
EXCITE Acoustics 2D and 3D Acoustic Post-processing
Fast and Subsequent Definable Result Evaluation on Arbitrary Positions and Field Point Meshes
23 7th European ATC, Munich, June 24th – 26th, 2014
2D Results: EXCITE Acoustics versus IBEM
EXCITE Acoustics v2014 Comparison with IBEM: Example I4 Demo – 3000rpm, 3rd Gear
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
0 500 1000 1500 2000 2500 3000
Inp
ut
Po
we
r [W
]
Frequency [Hz]
IBEM
EXCITEAcoustics
IBEM
EXCITE Acoustics
0
10
20
30
40
50
60
70
80
Mic1 Mic2 Mic3 Mic4 Mic5 Mic6
Ave
rage
Lev
el [
dB
]
IBEM
EXCITE Acoustics
IBEM
EXCITE Acoustics
Mic1
Mic2 Mic3
Mic4
Mic6
Mic5
24 7th European ATC, Munich, June 24th – 26th, 2014
Integrated AVL EXCITE - OptiStruct Software Solution Platform for NVH and Acoustics – Conclusion (1)
Customer Benefits
Shorter project turn-around times by simplified integrated work flows
Enhanced reliability by less risk for errors due to seamless data transfer between EXCITE and OptiStruct
Increased usability by functionalities enabled through the integrated EXCITE – OptiStruct solution platform
25 7th European ATC, Munich, June 24th – 26th, 2014
Integrated AVL EXCITE - OptiStruct Software Solution Platform for NVH and Acoustics – Conclusion (2)
Sound Radiation in Free Field with Wave Based Technique
Starts from unmodified structural FE mesh
direct use of FE model from structural vibration analysis (no need to close smaller openings, to change element types …)
Automated generation of acoustic mesh
preparation of calculation model with a few clicks
One model for the whole frequency range
no manual or automated mesh modification necessary to achieve an optimal balance between accuracy and calculation time
Subsequent definable post-processing
fast evaluation of results at additional arbitrary positions and field point meshes, no recalculation necessary
Significant short analysis lead time for calculation of airborne noise
02.07.2014
7th European ATC, Munich June 24th – 26th, 2014
Integrated AVL EXCITE - OptiStruct Software Solution Platform for NVH and Acoustics Bernhard Loibnegger AVL List GmbH Hans-List-Platz 1, 8042 Graz, Austria [email protected]
