Axon Automotive wanted to demonstrate their ability to design and build an ultra-fuel efficient vehicle using their cutting edge Axontex™ technology. The vehicle was intended to demonstrate the company’s ability to design a vehicle from the ground up, to accurately predict the crash performance of the vehicle and to build road going test mules to validate the design and Axontex™. Additionally the company set itself the objective of establishing a design approach that would enable it to tailor the stiffness of the vehicle depending on a customers preferred balance between cost, handling and weight.
- To engineer a carbon fibre space frame for a car with the ability to tailor strength and stiffness within customer specified targets
- To produce Finite Element Analysis (FEA) crash data and to validate the models with a series of physical tests culminating in a “sled test”
- To build a series of road going test mules to prove the design with a series of power train solutions including pure electric and petrol electric hybrid
The team had first to produce a schematic design for the vehicle to validate the core packaging requirements such as suspension, steering and cabin layout. The design had to work as a road going vehicle in a 2+2 City Car configuration. With this basic geometry signed off it was possible to design the vehicles space frame architecture to accommodate these packaging requirements.
Once this frame geometry was agreed the next output was to run FEA to model the performance of the frame in crash and also to analyse its torsional rigidity. The team had chosen to target a frame strong enough to pass crash test for a 600kg vehicle and to demonstrate torsion rigidity. By adjusting various material grades and thicknesses and running iterative models it was possible to produce a specification for a compliant structure.
With the design work signed-off we moved to designing and purchasing tooling to produce a short run of frames. With the tooling in place and material delivered by the fibre and resin suppliers it was possible to commence production of the beams and some panels and then move to production of the first frame.
Finally the team produced a small run of road going test mules and sled test structures to validate the design and the FEA model using real vehicle structures. These vehicles achieved road legal registration and were submitted to a series of crash tests to validate the FEA model. The end result was a proven methodology for an ultra-lightweight and safe carbon fibre space framed vehicle concept.
The team were able to deliver:
- A carbon fibre space frame vehicle with a 2+2 configuration and a weight of significantly less than 600 kg as both a pure EV and as a petrol electric hybrid.
- The final vehicle demonstrated the company’s ability to design a car to meet crash test and to tailor the design to meet customer stiffness targets.
- A validated route from extensive experimentation to a working FEA model for carbon fibre vehicle structures, especially in crash.
- A road legal technology demonstrator.
- Winner of the 2012 JEC innovation award – the composites’ industry equivalent of the Oscars.