Underwater implosion behavior of 3D-printed polymer structures

This study experimentally investigates the failure behavior of 3D-printed polymer tubes during underwater implosion. Implosion is a prevalent failure mechanism in the underwater domain, and the adaptation of new technology, such as 3D printing, allows for the rapid manufacturing of pressure vessels with complex geometries. This study analyzes the failure performance of 3D-printed polymer structures to aid the future development of 3D-printed pressure vessels. The 3D-printed tube specimens analyzed were fabricated using digital light synthesis (DLS) technology and included four different case geometries. The geometries consist of three cylindrical shells of varying diameter and thickness and one double hull structure with a cylindrical gyroid core filler. These specimens were submerged in a pressure vessel and subjected to increasing hydrostatic pressure until implosion failure occurred. High-speed photography and Digital Image Correlation (DIC) were employed to capture the collapse event to obtain full-field displacements. Local dynamic pressure histories during failure were recorded using piezoelectric transducers. The findings highlight that the 3D-printed polymers underwent significant deformation and failed at localized points due to material failure. The fracture of the specimens during failure introduced inconsistencies in pressure and impulse data due to the chaotic nature of the failure. Notably, the energy flow analysis revealed that the proportion of energy released via the pressure pulse was lower than in traditional aluminum structures. These findings contribute to our understanding of the behavior of 3D-printed polymers under hydrostatic pressure conditions.