Progressive collapse behaviors and mechanisms of 3D printed thin-walled composite structures under multi-conditional loading

Abstract

This work aimed to investigate progressive collapse behaviors and mechanisms of the 3D printed thin-walled composite structures under quasi-static compression and dynamic impact conditions. The thin-walled structures were manufactured by fused deposition modeling technique, using polyamide and fiber-reinforced polyamide-based composite. Four kinds of configurations (circular, triangular, quadrangular and hexagonal cross-sections) were studied. The experimental tests were carried out by a universal material testing machine for quasi-static compression (10 mm/min) and a drop hammer testing system for low-velocity impact (10 m/s). It was found that thin-walled composite structures presented progressive stable and regular plastic deformation mode under quasi-static compression. Under low-velocity impact condition, the thin-walled structures presented the progressive brittle crack-to-fractured collapse mode. The collapse mechanisms analysis revealed that plastic deformation mode consisted of bending deformation and membrane deformation. The fractured mode involved micro fiber breakage, fiber–matrix debonding and matrix cracks. With increasing the loading velocity, peak crushing force increased, while specific energy absorption decreased. The hexagonal structures made by carbon-fiber-reinforced material presented the best energy absorption performance under both quasi-static compression and dynamic impact conditions.