Smartphones-based in educational practice works: a case study of mechanical vibration practical works

Abstract

This paper presents three case studies of mechanical vibration manipulation using the smartphone, in purpose to exploit the smartphones in practical educational works. In this contribution, we focus on the use of the acceleration sensor integrated into the smartphones to capture the vibration signal of the vibratory phenomena such as the pendulum, beam vibration, rotating machines. In the first case, the main objective of the simple pendulum test is to determine the oscillation period (T), then the determination of the acceleration due by gravity (g). In the second case study, the objective of the beam vibration test is to determine the damping ratio (ζ) from the logarithmic decay (δ), then the natural frequency (ωn) of two different beams with different stiffness (aluminum, and brass beam). In the end, the purpose of the last study is to identify the vibration signature of the unbalance defect in rotating machinery, based on the amplitude and the phase shift of the vibration signal. The experimental results indicate that the smartphone presents acceptable results compared to the theoretical results, which support the validity of using smartphones in education to implement various experimental works.