Self-Sensing Structural Health Monitoring Capabilities of Lunar Regolith Simulant Polymer Concretes Incorporating Epoxy Nanocomposite Binders

To enable a permanent human presence on the Lunar surface, advances in technology leading to safer and more resilient structural materials are necessary. Materials containing high mass loadings of native Lunar materials, such as surface regolith, are also desirable because they have the potential to greatly decrease transportation requirements and cost per kg of deployed infrastructure. Structural health monitoring enables the observation of structures and components, either directly or via sensors, to detect or predict strain or damage, allowing for streamlined maintenance, reinforcement, or replacement of compromised elements. Recent advances have allowed such monitoring to be executed in situ via incorporation of carbon nanotubes into composite material binders. However, to date no research has applied these techniques to materials with high loadings of Lunar regolith simulant. This study uses a two-part epoxy binder doped with 0-3% MWCNTs by weight in an 18/82 mass ratio with LHS1 Lunar simulant to investigate the structural health monitoring capabilities of such materials. ASTM D695 compression specimens were tested in an Instron uniaxial testing rig at a displacement rate or 1.3 mm/min. A 10 kHz, 2 V amplitude AC current was passed through attached electrodes and resistance and reactance response was measured via a custom LabVIEW program. Analyses showed that not only can specific compositions enable the detection of strain, damage propagation, and individual damaging events via electrical measurements, but that early warning of changes in structural properties may also be achieved.