Structural Health Monitoring of Reusable Launch System Using Endovibrator-Type Wireless Sensors

Modern developments in aerospace industry are shifting towards lighter launchers and aircraft, where every parts are stringently optimized against weight. Within this new design paradigm, mechanical stresses rule of thumb is to be abandoned in favor of real measurement. This calls for lightweight embedded stress sensing strategies to assess the structural health without compromising it. This paper reports the proof-of-concept of new measurement approach to monitor wireless acoustoelastic tension. An endovibrator-type, batteryless wireless sensor is reported. It harnesses the acoustic resonances properties of a metal bolt, and is associated with a Wireless Power Transmission link at 8MHz. Mechanical tension, emulated through temperature variation have been wirelessly captured through the measurements of acoustic velocity variation and the monitoring of the endovibrator inner resonance frequency. A linear dependency is reported with -0.8 kHz/°C at 8.5MHz.