Micro Oscillator as Integrable Sensor for Structure-borne Ultrasound

Structural Health Monitoring (SHM) in Fiber Metal Laminates (FML) is based on the evaluation of Guided Ultrasonic Waves (GUW). At high frequencies, some GUW modes show no displacements at the structure surface. However, vibration information can be acquired from inside the FML. Serving this purpose, sensors need to be integrated into the laminate. State-of-the-art surface-installed piezoelectric ceramics are large and poorly matched to the surrounding material’s acoustic impedance. In this work, a custom structure-integrable Micro-Electro-Mechanical System (MEMS) based acceleration sensors is investigated for its functional compliance and suitability as an ultrasound pickup. The sensor inherent dynamic behavior is experimentally characterized. Consecutively, application-near SHM experiments are conducted and evaluated. Results demonstrate the sensor’s ability and limitations for recording structure-borne ultrasound.