Mono-material sandwich structures design produced by Foam Additive Manufacturing: study of performances under dynamic conditions

Abstract: The growing demand for environmentally friendly and lightweight solutions in structural applications highlights the importance of research for innovative materials and design methods to satisfy rigorous performance requirements. This research investigates the potential of the Foam Additive Manufacturing (FAM) process to create sustainable, high-impact-resistant materials. Foamed PLA specimens with tailored core densities were evaluated under low-velocity impact conditions, demonstrating up to 127% higher perforation energy than honeycomb infill structures of similar density. Sustainability in this approach stems from the use of biodegradable PLA, the avoidance of chemical blowing agents through the adoption of CO2 as a physical blowing agent, and the mono-material design, which facilitates recycling at the end of the product lifecycle. Additionally, the lightweight nature of the foamed structures reduces material consumption and enhances energy efficiency during use, particularly in applications requiring weight minimization. Detailed failure mode analyses revealed that foamed specimens absorb energy more efficiently due to mechanisms such as core indentation and foam cell collapse, achieving specific energy absorption (SEAρ) values up to 0.06 [Jm3 kg−1] for low-density specimen. Furthermore, based on the correlation between impact energy and sandwich density, the failure mode map highlights the superior impact resistance and progressive failure mechanisms of foamed specimens. These findings demonstrate the potential of FAM to bridge the gap between sustainability and performance, paving the way for innovative applications in fields such as packaging, automotive, and aerospace. Graphic abstract: (Figure presented.)