Additive manufacturing technologies enable the fabrication of crash boxes that are difficult to produce using conventional manufacturing methods. In this study, the crashworthiness performance of multi-cell crash boxes reinforced with face-centered cubic lattice structures, manufactured from PLA+ and ABS+ thermoplastic materials using the fused deposition modeling method, was investigated experimentally and numerically. Quasi-static axial compression tests were conducted to determine the crushing behavior of the structures, and the experimental results were validated using the finite element method. Experimental findings revealed that polymer-based lattice structures significantly enhanced the energy absorption performance of multi-cell crash boxes. Compared to unreinforced configurations, the total energy absorption increased by approximately 79% for PLA+ crash boxes reinforced with lattice structures, while an increase of approximately 100% was observed for ABS+ crash boxes. In PLA+ crash boxes, a limited increase of approximately 1.5% in peak crushing force was achieved due to lattice reinforcement. In contrast, lattice-reinforced ABS+ crash boxes exhibited an increase of approximately 30% in peak crushing force, indicating that ductile polymers are more effectively supported by internal lattice structures. Furthermore, the mean crushing force increased by approximately 80% for PLA+ crash boxes and 99% for ABS+ crash boxes because of lattice reinforcement. Despite the increase in structural mass caused by the lattice structures, the specific energy absorption improved by approximately 4% for PLA+ crash boxes and 9% for ABS+ crash boxes. A good agreement was observed between experimental and numerical results in terms of force- displacement responses and deformation modes. The obtained findings demonstrate that multi-cell polymer crash boxes reinforced with face-centered cubic lattice structures possess significant potential as lightweight and high efficiency energy absorbing components for automotive applications.
Mehmet Kopar (Tue,) studied this question.