Open Access

ARTICLE

Cost Optimized Non-Contacting Experimental Modal Analysis Using a Smartphone

by Jaafar Hallal^1,2,3,*, Mohammad Hammoud^2,3, Mahmoud Fakih^2,3,4, Ali Hallal^2,3

1 Mechanical Engineering Department, Faculty of Engineering, Lebanese University, Beirut, Lebanon
2 SDM Research Group, Mechanical Engineering Department, International University of Beirut, Beirut, Lebanon
3 Mechanical Engineering Department, Lebanese International University, Bekaa, Lebanon
4 Civil Engineering Department, Faculty of Engineering, Lebanese University, Beirut, Lebanon

* Corresponding Author: Jaafar Hallal. Email:

Sound & Vibration 2020, 54(4), 225-236. https://doi.org/10.32604/sv.2020.011513

Received 12 May 2020; Accepted 27 August 2020; Issue published 25 November 2020

Abstract

The vibrations behavior analysis is an essential step in the mechanical design process. Several methods such as analytical modelling, numerical analysis and experimental measurements can be used for this purpose. However, the numerical or analytical models should be validated through experimental measurements, usually expensive. This paper introduces an inexpensive smartphone as an accurate, non-intrusive vibrations’ behavior measurement device. An experimental measurement procedure based on the video processing method is presented. This procedure allows the measurement of the natural frequencies and the mode shapes of a vibrating structure, simply by using a smartphone built-in camera. The experimental results are compared to those obtained using an accurate analytical model, where the natural frequencies error is less than 2.7% and the modal assurance criterion is higher than 0.89. In order to highlight the obtained results, a comparison has been done using a high quality and high frame per second (fps) camera-based measurement of material properties. Since the highest recovered natural frequency and its associated mode shape depend on the frame per second rate of the recorded video, this procedure has great potential in low frequencies problems such as for big structures like buildings and bridges. This validated technique re-introduces the personal smartphone as an accurate inexpensive non-contacting vibration measurement tool.

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Keywords

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