Seven physical and one virtual demonstrator(s) were designed mostly in steel and aluminium intensive multi-material approaches as shown in Figure b) applying the technologies developed. In order to validate the design, defined but limited testing on fatigue, NVH and crash on module level was performed. Although not all attributes could be tested within ALLIANCE, the performed testing clearly demonstrated the validity of the new designs meeting all requirements considered important by the OEMs. The input data were provided and discussed with the respective industrial partner to ensure reliable input data as much as possible. The assumptions made and range of input data provided were applied to both, the reference part and the advanced lightweight Version so that the impact assessment is accurate in relation to each other. The final results of the impact assessment for each demonstrator module are shown in Table a. Over all considered modules a weight reduction of 32%, a reduction of 25% in kg CO2 eq. at 2.7 € additional costs for each kg saved have been achieved in total. However, the targets regarding relative weight savings and costs per kg-saved have not been met for all components but were compensated by components where the targets have been exceeded by far. However, the additional costs are still below 5 €/kg-saved, lower than the achievements in previous research projects and within the range accepted by the OEMs for C-D segments (VDI, 2014). Remarkable is that with a consequent design approach the overall production costs can be lowered for some components.
Table a: Summary of achievements on component level
Weight [%] GWP kg CO2 eq. [%] Costs [€/kg saved]
Door concept 1 -29,4 -18,3 +4,37
Door concept 2 -44,1 -43,6 +4,45
Rear floor panel -26,0 -20,1 -4,42
Hood -52,6 -55,9 +1,96
Front CMS -28,7 -22,7 -1,22
Front bumper beam -12,3 -9,9 +3,18
Rear bumper (EU version) -39,3 -23,3 -1,55
Rear bumper (US Version) -45,2 -39,2 -0,58
Strut tower w. integrated rail -35,0 -28,0 +1,53
Total -32,1 -25,1 +2,67
In order to assess the ALLIANCE technologies and solution on full vehicle level (see Fig. a), a virtual full vehicle model has been derived for an ICE and full battery electric vehicle (see above). All technologies were scaled and transferred into this virtual ALLIANCE full vehicle model demonstrating that affordable and sustainable weight reduction can also be achieved at full vehicle level. The virtual vehicle was first broken down into different modules (Fig. c) followed and the ALLIANCE Technologies integrated into the overall structural Concept. In doing so, lightweight design principles like one piece solutions or “right materials at right places” were applied consequently. The transfer and up-scaling of ALLIANCE technologies developed on component level resulted in a weight reduction of about 9.4 % on full vehicle level (ICE version). When exploiting also secondary effects additional 6.2 % weight savings can be gained resulting in a total saving of 15.6 %. This directly results in 10 % less energy consumption.
