Wireless Sensing of Temperature, Strain and Crack Growth in 3D-Printed Metal Structures via Magnetoelastic and Thermomagnetic Inclusions

2025-10-09

AI Summary

To address the challenge of real-time, in-situ monitoring of strain, temperature, and crack propagation in additively manufactured metallic structures operating under harsh conditions—currently reliant on inefficient periodic disassembly—this study pioneers the co-integration of magnetostrictive and thermomagnetic functional materials within microtubes, embedded directly into the metal matrix during additive manufacturing. Leveraging electromagnetic coil impedance modulation and eddy-current non-destructive evaluation principles, the approach enables wireless, passive, multi-parameter sensing within the structural interior. The method detects plasticity onset and fatigue crack initiation/propagation thousands of cycles earlier than conventional techniques, enabling condition-based maintenance. Experimental validation demonstrates strain measurement accuracy of ±27 με (full-scale 600 με), temperature accuracy of ±0.75 °C (0–70 °C, 95% confidence level), significantly enhancing in-service structural health awareness and service-life prediction fidelity.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
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• Application Domains: Internet of Things, Sensor Networks & Smart Cities

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Abstract

In this study, we demonstrate the first realization of wireless strain and temperature sensing within 3D-printed metallic structures using standard electromagnetic 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 during additive manufacturing. Mechanical and thermal stimuli affect the magnetic permeability of the embedded materials, which modulates the impedance of a coil placed on or near the surface of the printed part. We demonstrate strain sensing accurate to +/-27x10-6 over at least a 6x10-4 strain range, and temperature sensing accurate to +/-0.75oC over a 70oC range, both to a 95% confidence interval. We highlight these sensors' capabilities by detecting the onset of plasticity and fatigue-driven crack growth thousands of cycles before critical failure. This extends non-destructive eddy-current damage detection to accurate, real-time strain and temperature monitoring within metallic structures.

Problem

• Wireless sensing of strain and temperature in 3D-printed metal structures
• Detecting plasticity onset and fatigue crack growth before failure
• Extending eddy-current damage detection to real-time structural monitoring

Innovation

• Embed magnetoelastic materials in 3D-printed metal
• Use magnetic permeability changes for wireless sensing
• Detect strain, temperature, and crack growth wirelessly