Correlation of simulation_models_using_concept_modeling

Correlation of Simulation Models
using Concept Modeling
Dr. Jörgen Hilmann, Joe Abramczyk Ford Motor Company
Dr. Salvatore Scalera RLE International
Andreas Arlt SFE GmbH Berlin

Correlation of Simulation Models using Concept Modeling
Dr. Jörgen Hilmann, Joe Abramczyk, Ford Motor Company
Dr. Salvatore Scalera, RLE International; Andreas Arlt, SFE GmbH Berlin
Keywords: RADIOSS, HyperMesh, MotionView, SFE Concept, Correlation, Front Impact, Side Impact

ABSTRACT
Pre-requisite for efficient vehicle programs is the CAE driven development process as described in [1], [2] "Up Front CAE". Both CAD and CAE models
based on special Concept Software as SFE CONCEPT are used to analyze the attribute performance as safety, NVH or durability and commodity studies
concerning the weight, manufacturing, or package. A database of concept models is used to minimize the modeling effort and to maximize the re-usability of
components [3]. The accuracy of the models increases over time and leads to an increasing amount of available Concept models in databases. Due to the
increased acceleration of the development process, these models are critical in providing direction on vehicle architecture in the early stages of a program.
Due to the high importance of these decisions it is mandatory to trust the results of this early CAE models. Correlation of this Concept models to test or
reference mainstream CAE models creates the confidence in this approach. The correlation focuses on two aspects: 1. the level of detail required to capture
the detailed folding characteristic of the structure (e.g. siderail or B-Pillar) and 2. the process chain used to process the raw output from SFE Concept into
RADIOSS Include files (e.g. gap, contacts, spot-welding, adhesives, bolts). This process chain is implemented using HyperMesh in batch mode, details may
be found in [4]. This process chain is tuned to latest program modeling approaches and to meet the desired correlation status.
In this presentation RADIOSS safety concept models are correlated to different impact modes. Tools and methods are explained focusing on both the
automated evaluation of simulation output and the judgment of the correlation quality. The main criteria defining the correlation fitness are video overlay of
vehicle and dummies kinematics, curve comparison of vehicles acceleration, velocity, and intrusion. Furthermore the dummy sensors have been evaluated.
The combination of the above mentioned steps enable an accelerated and more confident concept phase allowing for more alternatives being analyzed in a
more holistic and detailed manner as described in [5], [3]. This is a pre-requisite for the creation of efficient designs under the constraints of an increasingly
accelerated development process.

BIBLIOGRAPHY
[1] E. Schelkle and H. Elsenhans,
"Virtual Vehicle Development in the Concept Stage – Current Status of CAE and Outlook on the Future", 3rd MSC Worldwide Aerospace
Conference & Technology Showcase in Toulouse 2001
[2] Jörgen Hilmann (Ford) und Uwe Wagner (Ford),
„CAE driven development process for the early vehicle development phase.“ IABC Confernce 2007 in Berlin
[3] Michael Keimes, Dr. Jörgen Hilmann, Martin Lichter, Dr. Uwe Wagner,
"Optimierungsstrategien für Leichtbauprojekte" VDI Leichtbaukonfernz Ludwigsburg, 2011.
[4] Jörgen Hilmann (Ford) und Hans Zimmer (SFE GmbH)
„Development and application of an automated model built process chain for the Preprogram and Concept phase using SFE CONCEPT and the Altair
Hyperworks package.“ EHTC Konferenz in Strassbourg 2008
[5] K.H. Volz and H.Zimmer,
"Optimizing Topology and Shape for Crashworthiness in Vehicle Product Development", IABC Confernce 2007 in Berlin

2011 European HyperWorks Technology Conference
Jörgen Hilmann, Joe Abramczyk, Salvatore Scalera Andreas Arlt

Correlation of Simulation Models using Concept Modeling

Contents

• Introduction
• Motivation for Concept Modeling
• Concept Models & Libraries
• Model built and Include Files

• Correlation quality: Procedure and Criteria
• Vehicle Samples
• Q&A


Introduction

Basic Design … is a Mini Product Development Department
Project Lead Project Lead Project Lead Project Lead
B-Car C-Car CD-Car Commercial

Body Exterior
Body
Body Interior &
Attributes
Electrical
Total Basic Design Team
Electrical with Matrix Organization
Chassis - Technical Specialists
Chassis & Veh.Dyn. - Supervisors
- Base heads
Veh. Dyn.
SQ & V (NVH) - Contractors

… Concepts

Vehicle Integration

Powertrain Integration
Link
to “LHS“
Mechanical Package


Separate CAE Attribute Workstreams – OLD State
Update Effort for each attribute & Risk for misaligned program assumptions
Model Quality

Dev. Time

Safety

Pre Upda Update Update 3 Update n
decessor te1 2
NVH
Pre-decessor Update Update Update
b c x
Durability
Pre-
Update Update
dece
I II
ssor

Concept Modeling in CAE driven development process
Usage of Concept Module Libraries & Standardized Pre-Processing Procedure & Include Assembly Process

Concept module library
• Concept libraries are populated during
the concept modeling work

• Re-use of concept modules increases over time
driven through best practice initiatives
e.g. for joint execution or Pillar designs

• A process chain is implemented using
Altair Hypermesh processing re-occurring
pre-processing tasks in automated batch mode Process Chain
meshing, using
HyperWorks package
• The full vehicle models are assembled from different in batch mode
sources using the RADIOSS Include files:

- Correlated CAE models / modules from the
RADIOSS
mainstream development teams Include
- Parts / Modules developed in the concept modeling Assembly
department using e.g. SFE Concept Process


Integrated CAE Attribute Workstreams – Current State
Update Effort shared among the team & No risk for misaligned program assumptions
Model Quality

Dev. Time
Baseline study Concept development Virtual design verification
Component studies & Iterations

Pre New model model update model update
decessor VCS 1 Level VCS 2 level VCS 3 Level

Safety NVH Safety NVH Durability
Safety NVH Durability


Price of the new process: Demand for Correlation
Starting the work from correlated reference models does not require up front preparation

• In order to built CAE concept model Concept module
confidence it is mandatory to verify the
predictive power of CAE Concept models
using correlation studies.

• Herein the full vehicle models (including the
concept modules) reflect the <Job #1>
design intent of the pre-decessor model.

• The Correlation-Phase is used to familiarize Modules from the reference model
the team with the new program and to
ensure the processes used are capable. Correlated reference CAE Model

• Two Objectives for Correlation: Substitution of concept modules
1. Geometry and Mesh level of detail
2. Process to built the full vehicle model Correlation of the new model

Analysis of concept alternatives
using the same processes


Correlation types
Starting the work from correlated reference models does not require up front preparation

Difficult to standardize the correlation approach,
due to differentiation through:
• Application to geometry or the model built process chain; or both.

• Applied Car Line: B-CAR / C-CAR / CD-CAR / Light Commercial Vehicles

• Availability of reference data: Mainstream CAE and/or real test results

• Different Impact Modes: Front, Side, Rear, …

• Different Requirements / Markets

As a consequence the correlation task is challenging and
the required timing difficult to predict.


Required accuracy of the model
The Level of detail is a function of the impact mode and

FORD FOCUS
SFE Concept Geometry

SFE Concept FE Mesh

Within Ford concept models
using the same numerical code,
e.g. RADIOSS for Safety analysis.
Mainstream CAE

The level of detail ranges between both:
- A rough box section to represent an inertia effect of structure, which
is not considered to deform
- A detailed geometry with all holes and depressions if considered
being important e.g. under axial compression in a frontal impact.

Correlation Sample: Frontal Offset
Key take aways of this presentation

ODB – EuroNCAP Frontal Offset / IIHS
Model correlation status is satisfactory for:

• Siderail behavior
• Overall intrusion values
(although slight under-prediction of Toeboard intrusion)
• Crash pulse

This CAE model is w.r.t. the offset impact
well suited to support A to B comparisons
of architecture studies

Displacement delta values

ridedown area
Upper_Cowl
Offset
Dashboard

CC_Beam
ToeBoard

A_Point
Conventional
Deformable
Cowl

CAE model
Barrier
64kph
Concept
Reference model -- -- -- -- -- -- -- model

Concept model
-14mm -1mm 2mm 3mm -6mm 2mm -3mm
delta to reference


Correlation Sample: Full Frontal Rigid Barrier

Straight Front – US-NCAP, SDG
Model correlation status is overall satisfactory
but there is a minor difference in the siderail bending.

As a consequence the pulse shape show
a slight deviation.

For A to B Comparisons may be used.

ridedown area
Upper_Cowl
Conventional
Dashboard

CC_Beam
ToeBoard

Full Frontal
A_Point
CAE model
Cowl

Rigid Barrier
56kph Concept
model
Reference model -- -- -- -- -- -- --

Concept model -12mm -15mm 2mm 9mm -3mm 2mm -5mm


Correlation Sample: Ford Mondeo Frontal Offset
Concept Upper Structure combined with mainstream residual modules

Dual Color Overlay: A to B comparison

Blue: Mondeo reference CAE model
Gold: Mondeo SFE CONCEPT Model
(with carry over parts e.g. Platform, PT,…)


Correlation Sample: Ford Mondeo Side Impact
Concept Upper Structure combined with mainstream residual modules

Blue: Mondeo reference CAE model
Gold: Mondeo SFE CONCEPT Model
(with carry over parts e.g. Platform, PT,…)
B-Pillar velocities B-Pillar velocities

@ @ B-Pillar-Mid
Striker

Door @ Pelvis @ Thorax
velocities


Correlation Method: Film / CAE Overlay
Overlay of a physical Test Film with a RADIOSS Crash Simulation: High Speed barrier side impact

0 ms

50 ms

AVI
100 ms


Correlation Method: Curve comparison using channels
Overlay of a physical curve measurements with RADIOSS time history readings

Accelerometer readings
Black: CAE model Black: CAE model B-pillar @
Gray: Test curves beltline
Gray: Test curves
Blue channel borders Blue channel borders A

B-pillar @
striker B

C
A B B-
pillar
@
rocker

Method:
Black: CAE model
Gray: Test curves - Create the average curve of all test curves
Blue channel borders
- Add ±15% of the average peak of the curves to define a channel
Observation:
• The accelerations evaluated using CAE model are almost always
contained in the band fluctuation of real acceleration
• The peak of the B-pillar_@_rocker acceleration is slightly
C underestimated


Correlation Method: Peak curve comparison
Overlay of a physical curve measurements with RADIOSS time history readings

Normalization: The bar charts represent the max. injury criteria
divided by the arithmetic mean of available test max. injury criteria.
“1” being the average of the available test curve maxima for this criteria, e.g. HIC36

Test Variation: The CAE results (orange bar) are in the range of test values,
except the Pubic Load for the 1st row and Spine Acceleration in the 2nd row.

1,45 1,55
1,40
1,35
1st row 1,50
1,45
2nd row
1,30 1,40

1,25 1,35
1,30
1,20
1,25
1,15
1,20
1,10
1,15
1,05
1,10
1,00 1,05
0,95 1,00
0,90 0,95
0,85 0,90
0,80 0,85
0,75 0,80
0,75
0,70
0,70
0,65
0,65
0,60
0,60
0,55
0,55
0,50 0,50
0,45 0,45
0,40 0,40
0,35 0,35
0,30 0,30
0,25 0,25

0,20 0,20
0,15
0,15
0,10
0,10
0,05
0,05
0,00
0,00 Ave5RibDis [mm] Iliac Fy
HIC36 MaxThoRib Abdomen Force Spine lowe Pelvis acceleration Pubic Fy HIC36 T12 acceleration [g´s]
acceleration Shoulder deflection [mm] T1 acceleration [g´s] Pelvis acceleration [g´s] Acetabulum Fy


Conclusions

• Concept modeling significantly changed the vehicle development
towards a CAE driven Development Process,
however requires to built confidence in the used simulation models.
Demand for correlation!
• Methods are presented using visual and statistical methods to determine
the correlation quality
• These methods are objective and measurable; they help to be as
accurate as necessary to reflect the system behavior without capturing all
details of one single test result,
prevents the risk of overfitting / overpredicting to one test.
• Having solutions for concept modeling, process chain and correlation
under control you can use this approach as a generic approach for
structure development.
• Very helpful is the coupling with Topology Optimization e.g. Optistruct.
and the consideration of system noises Robustness.

Jörgen Hilmann, Joe Abramczyk, Salvatore Scalera, Andreas Arlt

Selecting the best Subsystems
A holistic Approach of Evolution & Revolution

SWOT Architecture Study Topology Opt.
Demands / Wishes Altair Optistruct

• System xyz is not weight
efficient enough
• Demand to improve vehicle
performance abc Competitor Evolution “white Paper”
• Part t.b.d. is not package Reference Predecessor Part D Other Part F
model Part B Segment
efficient enough
Part A Part C Part E
•… Beam representation of
the major Load Pathes
incl. Sensitivities

Concept development considering all available findings

Materialgaugeoptimization and
Materialgrade optimization
?
Safety NVH Weight
ODB/FF Static / Dyn.


Thanks for your attention!

Correlation of Simulation Models using
Concept Modeling

Team of Authors:
Dr. Jörgen Hilmann, Joe Abramczyk Ford Motor Company
Dr. Salvatore Scalera RLE International
Andreas Arlt SFE GmbH Berlin

Correlation of simulation_models_using_concept_modeling

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