Beschreibung
Fiber metal laminates combine the strength of composites with the ductility of metals, making them ideal for lightweight aerospace structures. To assess their structural integrity, guided ultrasonic waves are used for structural health monitoring. For experimental validation of wave propagation models, structure-integrated sensors capable of locally resolving guided ultrasonic waves are required. This dissertation presents the development of such sensors based on MEMS technology. A pressure-sensitive silicon membrane is transformed into a piezoresistive micro-cantilever acting as a resonator. Operated in quasi-free mode, it detects displacements induced by guided ultrasonic waves and establishes the sensor concept. Analytical, numerical, and experimental investigations explain the resonators pseudo-nonlinear transfer behavior and its dynamic interaction with guided waves. A design iteration introduces a silicon paddle resonator with electromechanical differential mode rejection to suppress parasitic modes and extend the effective bandwidth. Embedded within fiber metal laminates, the sensors withstand autoclave fabrication and successfully acquire ultrasonic wave signals comparable to laser vibrometer measurements. By combining the operating principles of seismometers with MEMS microfabrication, this work establishes the MEMS vibrometer a new class of structure-integrable sensors for guided ultrasonic wave monitoring in advanced engineering materials.
Herstellerkennzeichnung:
Shaker Verlag GmbH
Am Langen Graben 15a
52353 Düren
DE
E-Mail: info@shaker.de
