The University of Glasgow has published a new analysis of the deformation mechanisms that lead to material fatigue in 3D-printed structures under load. These findings could pave the way for stronger and lighter plastics.
The research focuses on lattice materials – honeycomb-like structures known for their strength and energy absorption. The research team developed a design parameter to reliably minimize structural defects and maximize the performance of new lattice designs.
The study investigated the 3D printing process of polyetherimide (PEI), a robust, recyclable thermoplastic. Four different lattice designs in three relative densities were produced using fused filament fabrication and subjected to stress tests.
Professor Shanmugam Kumar from the James Watt School of Engineering explains: “3D printing allows remarkable control over material fabrication, but process-related defects can compromise the structures. Our aim was to build a comprehensive picture of these defects and develop steps to address them in the design process.”
The tests showed that low-density grids buckled and folded under pressure, while higher-density grids often broke along the PEI filament bond lines. This prevented optimal energy absorption.
Based on the test data, the team developed computer models for virtual tests. These revealed that overlapping plastic strands limited the energy absorption of PEI. The best performing grids had cell walls that were at most twice as thick as the PEI strand.
The design parameter was validated through real-world experiments and helps predict how removing manufacturing defects improves grating performance. Designers can use these calculations to create optimal structures.
The research, which began two years ago in collaboration with the University of Cambridge and the Marche Polytechnic University, was published in Advanced Materials Technologies. It was funded by the European Union and the University of Glasgow.
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