Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Experimental evaluation of a low-cost vibration sensor for modal testing applications
Submission Author:
Rafael Melo , SP
Co-Authors:
Rafael Melo, Luan Angelino, Pedro Cerântola, Sidney Bruce Shiki
Presenter: Rafael Melo
doi://10.26678/ABCM.COBEM2021.COB2021-0793
Abstract
Mechanical vibration manifests in all mechanical structures and systems. It can be responsible for unwanted noises, wear or even failure of parts due to fatigue. In this sense, the experimental characterization of mechanical vibrations is essential to control the life-cycle of a product subjected to dynamic loads. Experimental modal analysis techniques enable to extract modal parameters, such as resonance frequencies and mode shapes, which are important features of a structure when designing and monitoring these systems. However, a limiting factor for the implementation of vibration testing is the high cost of sensors and hardware commonly used for this kind of application. In the present study, the possibility of using low-cost microelectromechanical (MEMS) accelerometers is evaluated. Experiments were carried on a free-free beam, instrumented by MEMS accelerometers and commercial piezoelectric accelerometers used as reference sensors. A hammer testing was performed in the beam in order to extract the modal parameters of the system with both types of instrumentation. Two different modal extraction techniques were applied with these sensors. The first one was based on the traditional peak picking method (PP) used to extract modal frequencies and mode shapes from the estimated frequency response functions (FRFs) of the structure. The second approach was based on the frequency domain decomposition (FDD) which is an output-only modal analysis tool based on the singular value decomposition of the power spectral density matrix of the acceleration data measured in the structure. The PP and FDD algorithms are applied on the low-cost accelerometer and the professional one in order to compare the performance of both. Using the results of the professional sensor as a reference, the deviation of resonance frequencies and the modal assurance criterion are calculated to observe the discrepancies between the performance of both sensors. In the conclusions of the paper, the main advantages and drawbacks on the use of MEMS accelerometers for vibration testing are presented.
Keywords
Vibration Analysis, MEMS accelerometer, experimental modal analysis, vibration monitoring, low-cost modal analysis
