Enhancing passenger-bus crashworthiness through frontal structural reinforcement

• Original Structure Limitations: The initial bus structure absorbed 53 kJ of energy but failed to meet safety standards due to excessive deformation that could harm the driver. Despite low residual energy (157.22 J), the structure's deformation posed a significant risk. • Breakthrough in Structural Improvements: By incorporating thin-walled tubes into the frontal structure, energy absorption increased to 54.2 kJ. The hexagonal design offered the highest energy absorption (54.7 kJ), but rectangular tubes are recommended for practicality due to manufacturing challenges. • Enhanced Safety Features: The modified structure reduced residual energy on the driver dummy to 103.4 J and decreased deceleration from 16.1 g to 13.8 g, significantly improving safety compliance with ECE-R29 regulations. • Efficiency in Analysis: The use of the Virtual Topology command reduced simulation time by up to 3.95 times, enhancing analysis efficiency without compromising accuracy. Passenger buses are highly vulnerable to frontal collisions, which account for a significant proportion of severe accidents. This study addresses this issue by redesigning the frontal structure of buses to comply with UNECE R29 (Rev.2) crashworthiness standards. A thin-walled reinforcement framework was integrated into the frontal module and evaluated using explicit finite element simulation. The improved structure exhibits more stable deformation behaviour, enhanced crash energy management, and complete preservation of the ECE-defined survival space through the elimination of steering-assembly intrusion as defined by UNECE R29 (Rev.2). The peak deceleration was also substantially reduced compared with the original configuration, indicating smoother load transfer and improved structural crashworthiness. The improvement arise not from increased total energy absorption capacity but from more effective distribution of impact loads and greater deformation stability. Computational efficiency was further enhanced through Virtual Topology (VT), which significantly reduced simulation time. Overall, the findings demonstrate meaningful structural-performance improvements and provide a distinct contribution through the system-level integration of thin-walled reinforcements into a full bus structure under UNECE R29 (Rev.2), directly linking reinforcement design to survival-space preservation, steering-intrusion mitigation, and deceleration response while improving computational efficiency.