Engineers from Glasgow University and Italy have published new research providing fresh insight into the structural factors at play in the design of lattice materials – the honeycomb-like structures that provide strength and energy absorption properties while keeping constructions lightweight.

The team, part of which comes from the University of Glasgow’s James Watt School of Engineering, developed an ‘enhancement factor’, a way to predict how new lattice designs can be fine-tuned to minimise structural defects and maximise performance.

New guidelines for 3D printing based on the findings, published as part of a paper in Advanced Materials Technologies, could help material scientists develop new 3D-printed lattices with advanced properties.

This latest research details an investigation of the 3D printing process for a commonly used material called polyetherimide, or PEI, a thermoplastic that can be easily melted and reshaped, making it a useful, recyclable feedstock material for 3D printing.

The team subjected the materials to a series of stress tests, flexing, pulling and compressing them until they broke. Using micro-CT scans and thermal analysis after the tests, they found that low-density lattices, which contain more empty space than material, tended to buckle and fold under pressure.

They then used that data to develop computer models, allowing them to run virtual tests and explore how the materials would respond to real-world loadings. The results of this modelling showed that the PEI lattice was limited by defects introduced when more than two layers of plastic strands were laid next to each other.

The team’s enhancement factor method could help predict how removing these defects from the manufacturing process might improve the performance of a lattice design. In future, designers could use these enhancement factor calculations to create the best possible structures.

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These cellular materials are becoming more popular in sectors like aerospace, biomedical, automotive, marine, and defence because they could be used in things like impact absorbers or crash-worthy constructions.

Professor Shanmugam Kumar, the paper’s lead author, said: “We hope that our findings, and the guidelines we’ve developed, will lead to breakthrough new developments in materials produced by additive manufacturing. 

“Flawlessly-produced lattice materials could open up new advances in road safety, where their ability to absorb impact could help create more crash-resistant cars, or in aerospace design, where their lightness could enable more fuel-efficient aircraft.”