Residual Crashworthiness and Failure Behavior of Controlled Axially Precompressed 3D ‐Printed PETG ‐ CF Circular Tubes

ABSTRACT Despite extensive research on the crashworthiness of additively manufactured structures, their residual crashworthiness following controlled prior deformation remains largely unexplored. This study experimentally investigates the residual crashworthiness and failure behavior of controlled axially precompressed 3D‐printed PETG‐CF circular tubes under successive quasi‐static axial compression. The tubes were initially compressed to predetermined precompression levels (4%–16% of their original length), unloaded, and subsequently reloaded to complete collapse to evaluate their residual structural performance. During testing, load–displacement responses were recorded, and the corresponding deformation evolution and failure mechanisms were examined. The recorded responses were used to determine the initial peak crushing force (), absorbed energy ( E ) during the first and second loading stages, cumulative absorbed energy (), and crushing force efficiency (CFE). The results demonstrate that controlled axial precompression has only a limited influence on the collapse initiation resistance, with all precompressed specimens retaining more than 90% of the of the undamaged tubes (11.41 kN). Despite moderate variations in the residual absorbed energy, the tubes maintained comparable or improved E and CFE during reloading. The consistently exceeded that of the undamaged tube, reaching 142.61% (711.38 vs. 498.73 J) at the 16% precompression level. Failure analysis revealed that progressive folding remained the dominant collapse mechanism throughout successive loading, whereas localized cracking became more pronounced with increasing precompression but did not trigger catastrophic structural failure. These findings demonstrate the potential of 3D‐printed PETG‐CF circular tubes for reusable energy‐absorbing structures subjected to repeated loading.