1.3 - MEMS Vibrometer: Micro Modal Analysis
- Event
- iCCC2024 - iCampµs Cottbus Conference
2024-05-14 - 2024-05-16
Cottbus - Band
- Vorträge
- Chapter
- Condition Monitoring
- Author(s)
- J. Haus, A. Dietzel - Technische Universität Braunschweig, Braunschweig
- Pages
- 42 - 44
- DOI
- 10.5162/iCCC2024/1.3
- ISBN
- 978-3-910600-00-3
- Price
- free
Abstract
Automated structural health monitoring of modern fiber metal laminates requires the integration of ultrasound sensors into the inner layers of the laminate to be monitored. One requirement for struc-ture-integrated sensors is therefore that they have a minimal effect on ultrasound propagation. MEMS are suitable as ultrasonic transducers due to their size in the sub-wavelength range of ultrasound and due to their typical materials. MEMS-based acceleration sensors are the most commonly manufac-tured MEMS sensors and are used for structural monitoring in the construction industry, among other applications. In principle, inertial sensors integrated into lightweight structures are also suitable for measuring local acceleration due to ultrasonic waves passing passing through them. In practice, how-ever, there are no MEMS acceleration sensors for the ultrasonic frequency range. The reason for this is that the bandwidth of inertial acceleration sensors is inversely proportional to their sensitivity to the acceleration acting on them. The resonance frequency of the internal spring-mass system is decisive for the bandwidth. Its signal is only proportional to acceleration in the quasi-static frequency range (ω≪ω0). Inertial seismometers do not differ in their basic physical design from inertial acceleration sensors. In the quasi-free frequency range (ω≫ω0), they show an output signal proportional to the displacement of the sensor. The modal analysis of the oscillator system is fundamental to correctly model the transfer behavior. The results of the micro modal analysis are presented in this paper. Based on these, the dynamic behavior of the sensor is derived and discussed with reference to its application...