Wireless Embedded Sensing of Strain and Temperature

In this study, we demonstrate the first realization of wireless strain and temperature sensing within 3D-printed metallic structures using standard inspection hardware. This establishes a path toward need-based parts maintenance driven by accurate damage assessments instead of relying on regularly scheduled maintenance teardowns, extending the service intervals of structures operating in harsh environments. To this end, we encapsulate magnetoelastic and thermomagnetic materials inside microtubes and embed the sensing elements mid-print. Mechanical and thermal stimuli affect the magnetic permeability of the embedded materials, which modulates the induced voltage in a coil placed on or near the surface of the printed part. We demonstrate strain sensing accurate to ±25×10-6 over a 1×10-3 strain range, and temperature sensing accurate to ±0.75°C over a 70°C range, both to a 95% confidence interval. This extends non-destructive eddy-current damage detection to accurate, real- time strain and temperature monitoring in aluminum alloys and other metals.