An international team of engineers has given 3D-printed lattice metamaterials the ability to detect and map their own damage, by adapting electrical impedance tomography, an imaging technique borrowed from medicine. The plastic lattices are loaded with carbon nanotubes, and electrodes pass current through the structure while voltage differences are measured. As test specimens measuring 48 millimetres across were stretched to breaking point, the system produced real-time maps of where damage formed and how it propagated.
The method proved strikingly precise, localising damage to within roughly one strut of its actual position, including damage that developed far from the electrodes. The researchers also tracked deliberately built-in tiny cracks as they grew under strain, and found the system flagged accumulating damage before final failure, which points towards practical early-warning capabilities. All of the electrical readings were validated against direct observation of the structures as they deformed.
The work builds on the Sustainable Multifunctional Materials and Additive Manufacturing Lab led by Professor Shanmugam Kumar at the James Watt School of Engineering, with co-authors at the University of Glasgow and the University of Sydney. Published in Advanced Functional Materials, it was supported by University of Sydney and University of Glasgow Ignition Grants and a Vaibhav Fellowship. The authors see eventual applications in medical implants, aircraft parts and car bodies, while noting further development is needed.