Experimental and Numerical Investigation of ABS and PLA Material Crash Boxes Reinforced with Lattice Structures

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.