A design approach for lightweight car body construction with an example on the micro-car “ec2go”

With increase in demands for special purpose vehicles such as electric vehicles, small series production is gaining more importance in automotive industry. However due to restricted amount of resources available, these manufacturers have to face a number of challenges, high development costs, longer design-optimization loops, high manufacturing costs are some to name. Additionally, no compromise can be made with the passive safety and lightweight characteristics of the vehicle design. The “Flexbody” car body construction concept along with a methodical design approach “Intelligent Car Body (ICB)” aims at reducing these problems, although not completely eliminating them, by integrating “Intelligence” in the car body design process. The present work demonstrates this design approach with an example on a micro-car “ec2go”. According to the Flexbody construction concept, the car body of “ec2go” is constructed using profiles and joints, called as building blocks of the car body, keeping the styling and package requirements in mind. An optimum material combination is used for these car body components in order to construct a car body light in weight as well as safe in crash and stiffness loads. Inadequate amount of information available about the structural performance targets in the concept design phase of a vehicle is one of the main reasons for longer optimization loops during the design, and hence longer development times. The ICB design approach addresses this issue and targets to implement “Structural Intelligence” in the car body design process mainly for two tasks, namely, to define the performance targets for the desired car body during various crash scenarios and to develop an analytical design tool which can design the car body components to match these predefined targets. In order to facilitate the process of target definition a benchmark is developed by simulating two vehicles for crash. The analytical design tool under development is also validated by simulating car body relevant components for crush and crash loads and are being validated on the ec2go car body.

 

The Author

Authors: M.Sc. Anuja Nagle, Fachhochschule Aachen, Automobiltechnik-Labor Prof. Dr.-Ing. T. Roeth
Imperia GmbH Abstract