using cae & optimisation tools to design lighter and safer ...nafems world congress nafems uk...
TRANSCRIPT
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Using CAE & Optimisation Tools to
Design Lighter and Safer Train Seats
Marine Favre Decloux
GRM Consulting
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Seats Background
• M100 seat is a pedestal and wall mounted design, developed for Wabtec. Tested in
2013 at MIRA and passed all requirements of GM/RT2100 Issue 5.
• H200 is a development of M100 for HITACHI Rail Europe. Developed in 8 months,
passing the injury and integrity tests in 2014.
• M101 uses a combination of both previous designs and learnings from simulation and
tests.
• Each seat passed injury and integrity requirements of GM/RT2100 Issue 5 first time.
M100
H200
M101
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
GM/RT 2100 Issue 5
• New requirements for rail vehicle structures
• Document mandates requirements for the design and integrity of rail vehicle
structures for both primary and secondary structures, including interior
crashworthiness.
• Conflicting requirements between seat strength and passenger injury.
• At time of development, no other seats had successfully met requirements.
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Previous test knowledge
Material Data
Concept CAD & CAE scoping
studies
Master CAE
model
Design Design Design
Simulation Simulation Simulation
Test
Methodology
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Modal Analysis / Durability
Rearward & Forward Integrity
Forward Injury
Abuse Load Cases
Fatigue Load Cases
Methodology
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
1.5kN Forward1.5kN Forward
Injury
50%ile Rearwards
Integrity
95%ile Rearwards
100mm Lateral
2kN down
1.5kN Rear 1.5kN Rear
2kN down
1.5kN Grab Handle
GM/RT 2100 Seat Load Cases
Integrity
95%ile Forwards
Injury
50%ile Forwards
• All projects use finite design and
simulation resources.
• GRM’s approach has been to prioritise
load-case development
– Red – Checked & developed daily
– Amber – Checked weekly
– Green – Designed in from start
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Methodology
Manufacturability
Lightweighting
Cost
Strength & stiffness
Concept Design
Optimisation Tools
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Armrest Cover Ribs Optimisation
Abuse load cases to represent
150kg individual standing on trim
Initial Aluminium
armrest cover
Creation of candidate material
using RDM tool in Genesis
Topology
Optimisation Results
Definition of
manufacturing
constraints
Topology Optimisation
for multiple load cases
in Genesis
Optimisation keeps
solid element at the
locations where
reinforcements are
required
Initial Aluminium
armrest cover
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Armrest Cover Ribs Optimisation
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Reinforcement Derivation Method
• An existing FE structure is
our starting point
• The RDM® region is
automatically created in
Design Studio over the top at
user-defined limits
• Genesis carries out an
optimisation for multiple load-
cases, removing superfluous
material and only leaving the
most important parts
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Cantilever Pedestal Design
Package Space
DefinitionTopology
optimisation Design
Interpretation
Folded Sheet
Stiffness &
Modal
Final DesignSizing & Topology
optimisation refinement
Sheet thick. (mm)
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
• Forward and Rearward Integrity tested with two 95th percentile dummies on various
pitch and seat configurations (single/double/triple, 1st & standard class) to determine
the worst case scenario to be tested.
• Axial and shear forces measured at wall fixing points for bolt design.
• Plastic strain in pedestal and wall brackets recorded to ensure that the seat will remain
attached to the carriage. Seat-back longitudinal deflection recorded.
Crashworthiness & Seat Integrity
Loads (kN)
A B C D E F
Axial 32 14 -16 -13 33 9
Plastic Strain
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
• Injury values extracted from simulation of forward impact. Design changes were
quickly implemented and the subsequent change on injuries determined.
• Use simulation to determine the injury criteria closest to the legal standards defined in
GM/RT2100 Issue 5.
CriteriaGM/RT2100
LimitSimulation
Femur Load Left (kN)5.7
4.8
Femur Load Right (kN) 4.5
Knee Shear Left (mm)16.0
9.7
Knee Shear Right (mm) 10.9
Tibia Load Left (kN)8.0
1.1
Tibia Load Right (kN) 0.98
Tibia Index Left1.3
0.62
Tibia Index Right 0.75
Neck Tension (kN) 4.17 0.57
Neck Compression (kN) 4.0 1.10
Neck Flexion (Nm) 310 95
Neck Extension (Nm) 135 26
Neck Injury Criteria 1.0 0.61
HIC 500 96
3ms Clip 80 46
Injury Prediction
Peak force extracted
Cross-section View
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
• Adhesive testing was carried out by 3M on various
adhesive materials.
• A model was built to replicate the adhesive test procedure
with tiebreak contact between the aluminium sample and
the adhesive, which allows the failure force to be specified.
• The failure force value was set-up to achieve the same
failure characteristic seen in the adhesive test.
• Calibrated adhesive was then used to build accurate FE
model with material failure.
Adhesive Testing & Modelling
Sample
1
Sample
2
Sample
3
Sample
4Sample
5
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Seat Back Design
• Design sensitivity to seat-back shape / section profiles.
• Aim is to use the seat-back shape to absorb the energy of a crash to reduce
the leg injuries. Achieved through the unfolding behaviour of the section profile.
• Different shapes were tested to meet visual aspect requirements as well as
injury targets.
CriteriaGM/RT2100 Limit
CAE limit
(80%)Design 2 Design 8 Design 11
Femur Load Left (kN)
5.7 4.565.7 6.5 5.3
Femur Load Right (kN)
5.3 6.2 5.0
Knee Shear Left (mm)
16.0 12.813.2 13.0 11.9
Knee Shear Right (mm)
16.8 16.4 14.1
Design 2 Design 8 Design 11
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Seat Back Model
• Variation of thickness due to stamping was mapped on the seat back, based
on material thickness of 1.6mm.
• Thickness results used in the injury and integrity impact simulations to improve
the performance prediction.
Thickness (mm)
1.6mm based seat-back
CriteriaGM/RT2100
LimitCAE limit
(80%)
No Thickness mapping
With thickness mapping
Test Results
Femur Load Left (kN)5.7 4.56
5.3 4.8 4.6
Femur Load Right (kN) 5.0 4.5 4.2
Knee Shear Left (mm)16.0 12.8
12.1 9.7 8.2
Knee Shear Right (mm) 13.7 10.9 10.9
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Optimisation & Accurate
Predictive Modelling• CAE led design to meet all targets 1st time
• Optimisation tools to design lightweight, stiff and strong train seats
- RDM based on Topology Optimisation for internal reinforcement
- Topology Optimisation for cantilever pedestal design
- Combined Sizing & Topology for additional weight saving
• Test prediction highly depending on FE model quality
- Accurate adhesive model with failure from physical test correlation
- Stamping effect accounted for real seat-back thickness
- Dummy injury knowledge from previous automotive projects
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Forward Injury Test
CriteriaGM/RT2100
LimitSimulation Test
Femur Load Left (kN)5.7
4.8 4.6
Femur Load Right (kN) 4.5 4.2
Knee Shear Left (mm)16.0
9.7 8.2
Knee Shear Right (mm) 10.9 10.9
Tibia Load Left (kN)8.0
1.1 0.93
Tibia Load Right (kN) 0.98 0.72
Tibia Index Left1.3
0.62 0.72
Tibia Index Right 0.75 0.99
Neck Tension (kN) 4.17 0.57 1.19
Neck Compression (kN) 4.0 1.10 0.18
Neck Flexion (Nm) 310 95 127
Neck Extension (Nm) 135 26 26
Neck Injury Criteria 1.0 0.61 0.42
HIC 500 96 150
3ms Clip 80 46 62
• Forward injury test shows good correlation with simulation. Differences are mainly due
to dummy positioning.
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Rearwards Integrity Test• Rearwards integrity result is a pass as seat remains attached to rail structure and seat
is also well within the survival space envelope as predicted.
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK
Conclusions
• CAE analysis and optimisation tools made it possible to design three
generations of lightweight train seats, each passing both integrity
and injury tests first time.
• FE analysis saved time and money allowing the team to deliver a
design 35% lighter than standard train seats.
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NAFEMS World Congress 2015 | 21-24 June | San Diego | California | USANAFEMS UK Conference 2016 | 15-16 June | Telford | UK