The EDAG Light Cocoon was developed with a visionary approach towards a compact, dynamic sports car, with a fully bionically optimized, additively manufactured vehicle structure combined with a weatherproof textile outer skin.
The core idea of the concept is not to regard the body as a closed surface. Instead, an approach was adopted in which material was only actually used in areas where it was necessary for function, safety, and stiffness.
Simulation on the basis of a series bonnet
To first of all quantify and then verify the lightweight potential of a bionically designed structure, this approach was previously used, for example, in the design of the bonnet of a production vehicle, and then calculated. The point of the calculations was to confirm requirements, e.g. with regard to torsional and flexural stiffness and pedestrian protection.
A very simple geometry for the structure of the bonnet is not able to withstand the dynamic load cases, e.g. to meet head-impact specifications, as the hole pattern is too open. The diagram [in the upper-right-hand corner] shows the geometry that will meet the requirements of the head-impact test.
A topological CAE calculation simulation result confirmed that the basic stability requirements were met, and that a weight saving of about 25% was achieved with this bonnet.
Fabric outer skin
To protect the vehicle from the effects of the weather despite its open structure, but still meet aerodynamic principles, the leaf of a plant served as the blueprint.
Just like the structure of a leaf, which has a lightweight outer skin stretched over it, a lightweight protective skin covers the Light Cocoon. This textile fabric skin was supplied by the outdoor specialists Jack Wolfskin. The Texapore Softshell O2+ is a triple layered polyester jersey fabric that is extremely lightweight, durable, and watertight. Weighing no more than 19 g/m², the material supports maximum lightweight design requirements with minimum weight.
For the first time it is possible to consider the use of textile materials for the exterior, as these do not have any structural tasks to fulfill. An LED backlight concept creates an among the light, structure, and fabric in an attractive—and above all—innovative vehicle aesthetic.
Seamless mobility: the Light Cocoon’s spoiler
Apart from offering a high degree of lightweight potential, the use of a flexible textile also opens up other chances. Moving components can be covered easily as evidenced by the Light Cocoon’s mobile spoiler. The fabric performs every required movement without joins to detract from the vehicle’s appearance and is extendable components to generate downforce due to the airflow.
Solutions were created to solve the requirements for the vehicle’s spoiler to remain inflexible in its movement, for the cover plate to be bent, and also the length of the spoiler’s edge to be adjusted. EDAG experts found a matching PU material able to withstand the tensile stress and deformation. With the help of two infinitely variable servo motors, the spoiler can be electromechanically adjusted to suit the vehicle’s speed. Fully extended, the servo is 7 cm (2.8 in) high.
Personalization via accounts
With the EDAG Light Cocoon, a further dimension is that innovative exterior lighting technology enables the costumer to present his/her vehicle with a variety of lighting setups. With the vehicle, the concept of personalization takes one step further: features are no longer defined in the vehicle; instead, they are linked to a personal account. This makes the account-related activation of selected vehicle functions possible. The driver can, for instance make configurations and settings offline, and then activate them in the car. His/her data are always available without being directly dependent on the car. Also, the cloud-based mapping of some of the functions can transfer computing power away from the car.
EDAG plans to continue to keep a close watch on the evolution of additive manufacturing. The target: to develop practicable and valid applications for use in component development and production.
A number of selected, structurally relevant components using different materials and additive manufacturing methods were presented at the IAA 2015 in Frankfurt. In addition to this, the company will also continue to press ahead with subjects related to connecting the vehicle to the energy Internet and to the personalized car account.
With the futuristic concept of our Light Cocoon, EDAG wants to make a conscious contribution to stimulating the discussion about the future of lightweight construction and automobile production. As an engineering company, it sees as its task to make sure that it is today already working on technologies of the future and completely new approaches to vehicle development.
When it comes down to it, working on concept car projects like the Light Cocoon enables the product developers to build additional competencies within their company, while at the same time also encourage people to think outside the box and tread new paths to achieve the best possible technical solutions. Companies like EDAG, that develop the cars of tomorrow, must always keep their focus on the day after tomorrow.
Tobias Meyer, CEO, EDAG Inc., wrote this article for Automotive Engineering.