AVL software and related services support the entire range of virtual prototyping in the powertrain industry. Altair Engineering is used by a number of major automotive companies as their high-fidelity finite element analysis tool. The highest priority is given to the completion of the workflow for different use cases for strength and durability analysis of engine components as well as NVH analysis of engines and power units. All related simulation tasks are connected by specific interfaces to ensure reduction of overall workflow time and increase in project confidence. The dynamic behavior of engine components (crankshaft, connecting rod, piston, etc.) is simulated using AVL EXCITE as Multi-Body Dynamics (MBD) tool and central software in the workflow. Each component of the crank train and the engine/power unit structure is considered as flexible structure, performing local vibrations as well as global motion. The components are coupled within the MBD tool using various non-linear joints like the elasto-hydrodynamic bearing model. The model setup and meshing is performed with Altair SimLab, which has special plugins fulfilling EXCITE mesh requirements like inserting kinematic couplings at journal/pin center nodes and defining retained nodes at predefined areas. The model reduction is performed with Altair OptiStruct using a very efficient multi-level eigensolver (AMSES). OptiStruct directly generates the flexible body input data (.exb) for AVL EXCITE, whereas the required specification data is just a single command in the input file. After the dynamic simulation in AVL EXCITE the transient results can be passed back to OptiStruct for post processing transient or frequency response analysis. OptiStruct will than calculate motion, stresses and strains whereas results can be passed directly to .h3d or .op2 file format for further fatigue or airborne noise analysis with e.g. EXCITE Acoustics. An overview of the workflows for the use cases strength and durability analysis as well as NVH analysis, together with the integrated FEA tasks and the interaction between the different analysis tasks is given in the presentation. Speakers Bernhard Loibnegger, Senior software development engineer, AVL List G.m.b.H.

1. Bernhard Loibnegger
Daniel Baumann, IT
AVL List GmbH
(Headquarters)
Public
EUROPEAN ATC 2015 IN PARIS
Integrated AVL EXCITE – Altair Engineering
Software Solution for Durability and NVH
of Powertrain Systems

2. Bernhard Loibnegger | CDM | 25 Juli 2014 | 3Public
OVERVIEW
 What is AVL EXCITE
 Process scheme – AVL EXCITE Power Unit
OptiStruct coupling
 Model building w/ SimLab
 Flexible body generation w/
OptiStruct
 MBD simulation w/ AVL EXCITE
 Data recovery w/ OptiStruct
 Airborne noise w/ EXCITE ACOUSTICS
 New applications

3. Bernhard Loibnegger | CDM | 25 Juli 2014 | 4Public
AVL EXCITE - HIGHLY ADVANCED RIGID AND
FLEXIBLE MBD SIMULATION TOOL
Durability and Strength of powertrain
components
EHD Contact Analysis – investigation of
friction, wear and failure mechanisms, etc.
NVH - from system dynamics to vibration and
acoustics of engines, transmissions and entire
drivelines
Turbocharger – modal analysis and full high
speed rotor dynamics

4. Bernhard Loibnegger | CDM | 25 Juli 2014 | 5Public
AVL EXCITE - DURABILITY AND NVH OF POWER
UNITS AND DRIVELINES
Multi-level simulation models - analysis from concept to design on
component, sub-system and system level
Target Systems – automotive (conventional and hybrid powertrain),
transportation (ship, locomotive), electricity generation (gen-set, wind turbine)
and general industrial applications

5. Bernhard Loibnegger | CDM | 25 Juli 2014 | 8Public
PROCESS SCHEME – AVL EXCITE OPTISTRUCT
COUPLING
OptiStruct
OptiStruct Model CAD / FEM model
HyperMesh or SimLab
AVL EXCITE GUI
OptiStruct
AVL EXCITE
OptiStruct
.fem, .bdf
.fem, .bdf
.exb
.INP4
.h3d or .op2 for Fatigue Analysis
Model Building
Condensation Setup
Substructure and
.exb File Generation
w/ AMSES
MBD Analysis
Displacement, Stress and
Strain Recovery
Post-Processing
Flexbody
.h3d

6. Bernhard Loibnegger | CDM | 25 Juli 2014 | 9Public
MODEL BUILDING
CRANKSHAFT MESHING FOR AVL
EXCITE WITH SIMLAB
 Surface and volume mesh templates to
get proper RBE3 couplings
 ASET / ASET1 can be defined in SimLab
using Sets Dialog tool
 Interface nodes and their corresponding
Degree of Freedom can be specified
 Option to Setup OptiStruct job to create
.exb file for AVL EXCITE Analysis
SimLab

7. Bernhard Loibnegger | CDM | 25 Juli 2014 | 10Public
FLEXIBLE BODY GENERATION
CMS REDUCTION W/ OPTISTRUCT
 Use PARAM,EXCEXB,SMOT/CON6
to generate AVL EXCITE body property
file .exb
 AMSES can be use for large problems
(2 to 10 times speedup)
 Non-matching meshes can be combined
with tied contact
 Use Surface to Surface (S2S) with
type=FREEZE
 Only portions of the model can be
outputted for recovery
 Use DISP=SID, where SID is just the
surface grids
 Use GPSTRESS=SID
OptiStruct

8. Bernhard Loibnegger | CDM | 25 Juli 2014 | 11Public
FLEXIBLE BODY GENERATION
CONTENT OF .EXB FILE
 The GRID information (ASET and
OSET)
 The GRID point location
 The condensed mass, stiffness,
and viscous damping matrices
 The eigenvalues and eigenvectors
of the condensed system
 The full or partial mesh
displacement recovery matrix
(default is ALL)
 Inertia Invariants
 With PARAM,EXCEXB,CON6

9. Bernhard Loibnegger | CDM | 25 Juli 2014 | 12Public
MBD SIMULATION W/ AVL EXCITE
SETUP EXCITE MODEL
 Define bodies (type and link to .exb file)
 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.

10. Bernhard Loibnegger | CDM | 25 Juli 2014 | 13Public
DATA RECOVERY W/
 Modal participation coefficients are passed
back to OptiStruct
 Stored in .INP4 file
 Multiple types of data recovery using data
from the Altair .h3d file.
 Displacement, Velocity, and Acceleration
(Real or Complex or Magnitude /Phase)
 Stress and strain
 No DMAP is required
 Just use an ASSIGN statement for each
.INP4 and .h3d file
 Multiple analysis types supported
 Frequency Response
 Transient Response
 Multiple Analyses in a single run
 Can post-process Transient and Frequency
Response in a single run
ASSIGN,H3DDMI,AX,name.h3d
ASSIGN,EXCINP,10,model_SOL109.INP4
ASSIGN,EXCINP,20,model_SOL111.INP4
VELOCITY = ALL
SUBCASE 10
LABEL = TRANSIENT RESPONSE
…
SUBCASE 20
LABEL = FREQUENCY RESPONSE
…
OptiStruct

11. Bernhard Loibnegger | CDM | 25 Juli 2014 | 14Public
NVH POST-PROCESSING
 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
SPECIAL STRUCTURE-BORNE NOISE
W/ EXCITE EVALUATION TOOL
Integral Surface Normal Levels
Oil Pan
IntegrsalLevel[dB]
630 800 1000 1250 1600 2000
1/3 Octave Centre Frequency [Hz]
EHD2
NONL
10 dB
 Integral levels of structure parts
(selection by material / element
property or direct)
 Integral levels of structure parts versus
engine speed or any other parameter

12. Bernhard Loibnegger | CDM | 25 Juli 2014 | 15Public
EHD RESULTS AND STRESS RECOVERY

13. Bernhard Loibnegger | CDM | 25 Juli 2014 | 16Public
AIRBORNE NOISE W/ EXCITE ACOUSTICS
HIGHLY EFFICIENT SOUND
RADIATION CALCULATION
 From model to result in
shortest time
 Patented, unique,
automated meshing of
acoustic model
 One acoustic mesh for the
whole frequency range
 Fast and flexible post-
processing

14. Bernhard Loibnegger | CDM | 25 Juli 2014 | 17Public
AIRBORNE NOISE W/ EXCITE ACOUSTICS
EXCITE ACOUSTICS V2015
 New integrated SDT based 2D/3D Post-
processor
 Interactive, connected 2D/3D results
on one page
 Predefined and User customizable
templates for reporting
 Export of results at microphone
positions as audible files (*.wav)
 In progress to offer EXCITE
ACOUSTICS as Altair Partner Solution.

15. Bernhard Loibnegger | CDM | 25 Juli 2014 | 18Public
NEW UPCOMING FEATURE – THERMAL LOAD
EHD WITH NON-STATIONARY
THERMAL BOUNDARY CONDITION
Workflow
 Evaluation of cyclic average heat flow
into structure
 Coupled steady state temperature –
displacement FE analysis w/ OptiStruct
 Direct import of 2D temperature and
radial deviation profiles from .op2 at
joint properties (EHD2+T & EPIL)
Temperature Deformation
Benefit
 More accurate heat flow, structure and
oil temperature values for design and
failure analysis

16. Bernhard Loibnegger | CDM | 25 Juli 2014 | 19Public
NEW UPCOMING FEATURE – FRETTING
FRETTING EVALUATION
Method
 Non-linear FE contact analysis w/ OptiStruct of
the assembled bearing shell using transient EHD
pressure distribution as boundary conditions
EXCITE Utilities
Example: FIP
Fretting Assessment
 Fretting Wear (FDP or FWP) to assess friction
rust, pitting and damage of surface
 Fretting Initiation Parameter (FIP) to access
crack initiation parameter and fracture of
component
 Fretting Fatigue Parameter (FFP) to access
structure durability

17. Bernhard Loibnegger | CDM | 25 Juli 2014 | 20Public
NEW UPCOMING FEATURE – FLEXIBLE GEAR
ADVANCED GEAR JOINT – FLEXIBLE
WHEEL BODY
Model Approach
 Wheel body as condensed FEM-model
with specific rules for ASET node
locations -> new SimLab task
 Fundamental tooth elasticity (bending,
tilting in body) by established analytical
approaches
Advanced Gear Joint
Mi
Mj
Fi
Fj
VCN
(‘Virtual Center
Node’)
Gear Wheel as
Flexible Body
(condensed FEM
structure)
Tooth tilting Tooth bendingFlank contact
Tooth tilting Tooth bendingFlank contact
Flank-
Contact
(Hertz)
Bending Tilting
Tooth tilting Tooth bendingFlank contact
Analytical tooth
deflections
ASET
Nodes
Benefit
 Investigate the influence of wheel body
vibrations and deflections on local gear
contact

18. Bernhard Loibnegger | CDM | 25 Juli 2014 | 21Public
NEW APPLICATION - TURBOCHARGER
ANALYSIS
High Speed Rotor Dynamics
 Influence of interaction with
floating bushing bearings
 Detection of critical speeds
 Displacement at various rotor
positions
 Orbital path at rotor ends
 Unbalance investigation
Investigation of Floating Bushing
Bearing Behavior
 Influence of oil properties
 Ring rotation speed, influence on oil transport
 Oil flow through bores in bushings
 Optimal compromise for bearing clearances
 Bearing design – full versus semi-floating

19. Bernhard Loibnegger | CDM | 25 Juli 2014 | 22Public
TURBOCHARGER RESULTS

20. Bernhard Loibnegger | CDM | 25 Juli 2014 | 24Public
ADVANTAGES OF THE OPTISTRU INTERFACE
TO AVL EXCITE
 Efficient generation of AVL EXCITE condensed bodies further enhanced by an interface
to AMSES for large problems
 The ability to tie together components with different meshes during the condensation
calculations
 The ability to preload components for condensation (coming in OptiStruct 14.0)
 The complete lack of need for DMAP, scripts, or macros for both the body generation as
well as the results recovery analysis
 The ability to perform multiple results analyses simultaneously
 The ability to output only a portion of the model to reduce file sizes as well as run times
for AVL EXCITE and results recovery calculations
 Direct output of .op2 or .h3d file for fatigue: no results translation required.
OptiStruct

21. Bernhard Loibnegger | CDM | 25 Juli 2014 | 25Public
DIFFERENTIATORS - AVL EXCITE
 power unit application oriented solution
 fast solver capable to efficiently handle large flexible
models
 multi-level approach – modeling depth adjustable to
stage in EDP and application target
 best-in-class lubricated contact models (EHD) for
design, friction, wear and failure analysis of slider
and thrust bearings, pistons and piston rings
 accurate, transient engine operating conditions
enable designs close to the endurance limits
 system approach for accurate structure- and airborne
noise results
 high level technical support and service for method
development and projects

22. www.avl.com
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