Crashworthiness and Lightweight Design of Glass‐Fiber‐Reinforced Polycarbonate/Polybutylene Terephthalate Composite Bumper Beams

ABSTRACT Against the backdrop of electric vehicles prioritizing safety and lightweight design, glass fiber (GF) reinforced polycarbonate (PC)/polybutylene terephthalate (PBT) composites offer innovative solutions for automotive collision safety and weight reduction due to their superior strength, energy absorption capacity, and lightweight properties. Based on the equal stiffness theory, this study designed a rectangular PC/PBT/30GF composite rear bumper beam. Low‐speed frontal and side collision simulations were conducted to extract key performance indicators including displacement, energy absorption, and peak force, which were then compared with those of a conventional aluminum alloy bumper beam. To enhance the energy absorption capacity and structural stability, structural design comparison and thickness parametric screening were conducted. Three cross‐sectional designs with integrated stiffeners were proposed, and the three‐chamber rectangular structure was identified as the optimal solution through collision performance comparison. Further thickness optimization was conducted for weight reduction, demonstrating that the beam exhibited exceptional collision performance when the cross‐sectional thickness was reduced to 5.40 mm. Compared to the aluminum counterpart, the optimized composite beam achieved a 4.5% mass reduction and an estimated 35.1% reduction in material cost, demonstrating potential advantages in lightweighting and material‐cost control.