Crashworthiness Behavior of Additively Manufactured PLA, Nylon, and Wood Multicell Tubes under Axial and Lateral Quasi-Static Loading

Abstract

Crashworthiness, which is defined as the ability of a structure to absorb impact energy through controlled, gradual deformation, is an important factor in the design of lightweight energy-absorbing structures. This study describes the crashworthiness behavior of multicell tubes with different internal cell geometries that have undergone quasi-static compression. Polylactic acid (PLA), nylon, and wood filaments were utilized in fused deposition modeling (FDM) to create thin-walled tubes with cross-shaped, equal-shaped, and strict inequality-shaped internal cell arrangements. The effects of material, internal geometry, build orientation, and loading orientation on the crashworthiness performance were analyzed experimentally. The cross-shaped design demonstrated the best crashworthiness performance among the examined configurations, especially for PLA specimens. The cross-shaped PLA tube produced the highest specific energy absorption (SEA) value of 10.75 J/g under axial compression, characterized by sequential folding deformation. Additionally, the specimens with a 90° orientation showed the most stable progressive collapse behavior and the greatest energy-absorption capacity. In comparison to PLA specimens made at a 90° build orientation, those made at a 45° and 0° build orientation absorbed 8.8% and 85.1% less energy, respectively. However, the wood specimens displayed the most severe brittle fracture, especially at lower build orientations. Under lateral compression, the cross-shaped arrangement offered the best compromise between structural weight and energy absorption (EA) capacity among the geometries examined. This result can be useful for the development of optimal energy-absorbing 3D printed thin-walled multicell structures, such as protective components and lightweight transportation structures.