Embedded Piezoelectric Sensing for Metallic Components: A Novel SHM Architecture for Self-Aware Structures

This study presents a novel structural health monitoring (SHM) architecture for selfaware structures based on hybrid manufacturing for fabricating multifunctional metallic components with subsurface-embedded piezoelectric (PZT) sensors, enabling autonomous SHM capabilities. The developed methodology integrates Wire Arc Additive Manufacturing (WAAM), subtractive machining, and Cold Spray Additive Manufacturing (CSAM) to seamlessly embed commercial off-the-shelf PZT sensors within aluminum structures (Al-5356) while preserving structural integrity. The embedded sensors are protected by ceramic thermal barriers and metallized surfaces, facilitating process resumption for complex geometries. The experimental validation is based on acousto-ultrasonic guided wave (GW) propagation analysis under controlled mechanical loading (0-100 MPa) and thermal cycling (ambient to 100oC). Active-sensing configurations utilizing pitch-catch methodologies demonstrate equivalent performance to surface-mounted sensors, with capacitance-based electromechanical impedance signatures confirming sensor functionality. The fabricated self-sensing structures exhibit realtime diagnostic capabilities for detecting operational (static load) and environmental (temperature) state changes, demonstrating particular advantages for applications where surface-mounted sensors are impractical due to coating requirements or environmental protection constraints. This hybrid manufacturing framework establishes a foundation for next-generation intelligent metallic structures with integrated SHM functionality.