Lightweight Design and Crash Safety Analysis of an Autonomous Electric Minibus Superstructure

The development of autonomous electric minibuses offers a promising solution for sustainable and efficient short-to-medium-range public transportation, particularly within controlled environments. This study presents a comprehensive approach to the structural design and crashworthiness assessment of an autonomous electric minibus superstructure, addressing the challenges of lightweight construction and enhanced safety performance. A systematic material selection methodology using Ashby plots identified ASTM A36 steel as the appropriate material, achieving superior performance-to-cost ratios compared to aluminum alloys and composite materials. The baseline superstructure design accommodated nine passengers while maintaining UNECE R107 compliance. Finite element analysis using LS-DYNA revealed critical safety deficiencies: lateral deformation of 270 mm under ECE R95 side-impact conditions and pedestrian injury criteria exceeding safety thresholds for HIC of 1,336 and chest acceleration of 65.9g. Targeted structural modifications including increased door pillar thickness, integrated wheel arch reinforcement, and strategic floor cross-member addition achieved a 65.9% reduction in side-impact deformation while reducing structural mass by 7.7%. A parametric study of front-end geometry identified the suitable configuration with 7° front inclination and 1,250 mm rake height, achieving 75.7% reduction in HIC (to 324.7) and 29.1% reduction in chest acceleration (to 46.7g), both satisfying international safety standards. The systematic design approach can simultaneously achieve lightweight construction, regulatory compliance, and enhanced safety performance for autonomous electric minibuses.