This paper proposes an engineering process for optimising new Full Electrical Vehicle (FEV) lightweight vehicle architecture based upon OptiStruct topology optimisation, extracting the idealised load paths for a given set of load cases. Subsequently, shape and size optimisations (HyperStudy) are conducted in order to obtain detailed information of localised vehicle geometry, including automated 2D mesh generation from 1D beam models. The research discusses each individual step of the overall process including successes, limitations, and further engineering challenges and complications which will need to be resolved in order to automate the vehicle architecture design to include durability and (dynamic) crashworthiness performance.

1. Optimising FEV BIW Architecture
from a Styling Envelope
Jesper Christensen
Coventry University, UK

2. Agenda
• Introduction
• Purpose & proposed methodology
• Topology optimisation
• Lessons learnt
• Crash structure and safety cell
• “Automation”
• Shape & size optimisation
• Crash structure development
• Safety cell development
• “Automation”
• Conclusion and future steps

3. Introduction
• Low Carbon Vehicle Technology Project, ongoing TARF
• £29 million research project
• Project partners:
Define a methodology for developing a
lightweight vehicle architecture (BIW)

4. Purpose & proposed methodology
• Define a methodology for developing a lightweight architecture
• Requirements:
• Vehicle may be Fully Electric (FE) or Hybrid Electric (HE)
• How?
• “Conventional” BIW development
• Optimising “pre-existing” BIW
1.CAD model (design envelope)
• Blank sheet use optimisation
2.Topology optimisation
Overall aims:
3.Shape- & size optimisation
Minimise BIW mass
Meet safety requirements
4.BIW draft

5. Topology optimisation
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft

6. Topology optimisation
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft
15-20 minutes / model
30 seconds / model
GUI – “Automatic” topology optimisation setup - tcl
Barrier Wheel and Auxiliary Constraints
Creation suspension components

7. Topology Shape- & size optimisation
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft
Safety cell

8. Shape- & size optimisation
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft

9. Shape- & size optimisation
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft
Crash structure
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10. BIW draft
1. CAD model (design envelope)
2. Topology optimisation
3. Shape- & size optimisation
4. BIW draft
Crash structure Safety cell
BIW draft

11. Conclusion and future steps
1.CAD model (design envelope)
Conclusions:
Good for (rapid) initial BIW load path estimations 2.Topology optimisation
Good for safety cell development
Inertia Relief
Limitations of linear elastic software 3.Shape- & size optimisation
Interpretations of results are vital
HM tcl scripting enables rapid model setup
4.BIW draft
Future steps:
Non-linear topology optimisation (ESLM?)
Joint modelling (multiple materials)
Increased consideration of manufacturing constraints
Consideration of shape- and size opt. within topology opt.
Combined linear and non-linear topology optimisation

12. Conclusion and future steps
1.CAD model (design envelope)
Conclusions:
Interpretations of results are vital 2.Topology optimisation
3.Shape- & size optimisation
4.BIW draft
Future steps:
“Automatic” / mathematical extraction of results CAD model

13. Conclusion and future steps
1.CAD model (design envelope)
Conclusions:
Excellent for lightweight crash structure development 2.Topology optimisation
Robust, stable and efficient response surfaces
Excellent coupling with Dynamic modelling
Excellent sampling point options 3.Shape- & size optimisation
4.BIW draft
Future steps:
“Automation” / template building (as topology setup)
“Direct link” with topology optimisation

14. Thank you for your attention – any questions?
Jesper Christensen
Lecturer in Stress Analysis
aa8867@coventry.ac.uk
Christophe Bastien
Principal Lecturer Automotive Engineering
aa3425@coventry.ac.uk
Mike V Blundell
Professor of Vehicle Dynamics & Impact
cex403@coventry.ac.uk