SuperLIGHT-CAR (SLC) is a collaborative Research & Development project co-funded by the European Commission under the 6th Framework Programme.
SLC has a multi-material philosophy, striving to use for each part the best material and manufacturing processes in terms of weight and cost minimization, while fulfilling a wide range of automotive requirements in areas such as stiffness, crash performance, fatigue and corrosion resistance, etc.
The pre-competitive achievements of SuperLIGHT-CAR applied in series production beyond 2012 will serve a basis to save millions of tons fuel respectively carbon dioxide due to significantly reduced vehicle weight.
Fig. 1: EUCAR roadmap towards multi-material concepts
The core driving force for SuperLightCar has been from the start a group of seven European carmakers: Volkswagen (as coordinator), Fiat Research Centre, Opel, Renault, Volvo Technology Centre, Porsche and Daimler. These, together with top-level organizations from science as well as the supplier industry have defined the SuperLIGHT-CAR approach.
SuperLIGHT-CAR coordinates with other major RTD projects co-funded under the 6th Framework Programme through the EUCAR umbrella (EUCAR: European Council for Automotive Research) and is part of the EUCAR technology roadmap towards the realization of multi-materials’ concepts (fig 1).
Project objectives
The mission of SuperLIGHT-CAR is the realization of advanced multi-material vehicle structures using break-through technologies for economic and sustainable lightweight design. The overall objective is the realization of vehicle structures achieving:
• Weight reduction of compact class car body structure more than 30 %
• Ensuring structural performance (crash, static, etc.) of today‘s mass produced body structures in compact class
• Light weight design cost reduction (Specific light weight costs: ≤5 €/kg)
• Capability for large series production
• Innovative multi-material design concepts
• Recyclability / Sustainability
• Contribution to reduction of CO2 emissions (-85kg ~ -8gCO2/km)
• Initiating further downsizing of vehicle concepts
Progress towards SLC Objectives
After 36 months, SLC has made substantial progress towards its objectives.
>> Multi-material concepts
The three concepts developed during the 2nd year of the project were evaluated and integrated into one general SLC vehicle concept.
• The Universal Light Body Concept (ULBC) has been developed considering all boundary conditions from the start (performance and production volumes) and under more stringent cost requirements (< 2.5 € / kg saved).
• The Super Light Body Concept (SLBC) was designed focusing on maximising weight savings under more relaxed cost targets (< 10 € / kg saved).
• Besides the SLBC and the ULBC concepts, the SuperLIGHT-CAR partner ArcelorMittal has developed the Steel Concept, a mono-material concept using the latest steel grades for achieving a cost-effective weight reduction.
Fig. 2: Summary of the 3 SLC concepts
Since January 2007, the SLC consortium has worked to converge the 3 developed vehicle concepts into 1 concept.
The material mix in the final SLC body concept is fully multimaterial: Steel parts account for approx 50% of the total weight of the body in white, but using many grades of steel. Aluminium, also in different grades, is used till approx. 35% of the total weight. The rest of the weight is due to Mg parts and plastic parts, with approx. 7% and 8% respectively.
Fig. 3: SLC final concept
>>Forming and joining
After 3 years work, manufacturing and joining technologies (SLC technologies’ portfolio) keep their promise to reach the requirements of mass-production.
Metals:
The technological development (supported through forming simulation) has considered different materials formulation (e.g. new FeMn steels, new Al alloying elements) and process parameters setup (e.g. steel hot stamping, Al warm forming,).
Plastics:
RTM structural parts offer high weight saving potential. However, costs and cycle-times are still too high. That is why the efforts for this technology have been focused in reducing costs.
LFT technology development has been focused on achieving A-class appearance and on having plastic materials fully compatible with the standard production line .
Joining:
The state-of-the-art and new joining technologies have been analysed for their application within SLC and according to this analysis, the joining methods, processing parameters and setup for each subassembly have been defined.
A standard production layout has been defined by SLC, together with basic hypothesis for the definition of the model. To test the first evaluation data, a first prototype of the mathematical model has been developed.
Fig. 4: Plant layout
>>Tools
SLC has reached significant progress towards the completion of its simulation toolbox for multi-material concepts regarding cost, LCA and recyclability. This toolbox covers static, crash and fatigue performance.
The testing program for crash and fatigue characterisation has been based in tests of shear-tension with various joining techniques.
Following the completion of the Cost-Weight-Optimisation tool (to be used in early design stages when most costs are incurred), the tool for more detailed cost calculations has been further developed and preliminary used in the assessment of the ULBC, SLBC, steel intensive concept and SLC final concept.
The SLC Cost Tool is highly automated, in order to be very easy to use by automotive designers.
Fig 5: Conceptual framework for the SLC Bridge
The tool for integrating LCA and cost assessment into CAx environments is also available (SLC Bridge). This tool empowers designers to perform quick A-B comparisons between different design alternatives in an environment they are familiar with. Thus, SLC is being successful in integrating sustainable and cost aspects into the initial stages of the design process of multi-material concepts.
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