June 24, 2017
June 24, 2017
June 28, 2017
Computers in Education
This vibrations course is traditionally entirely theoretical with simulated results being plotted. Students do not directly see the connection between the plots on paper and how systems behave in reality. There is no lab associated with the course, so students have a disconnect between what they are solving for and its application.
A testing apparatus was set up in a lab room. A 3’-long solid Aluminum 6061 beam with 3” x 2” cross section was suspended from a ladder with free-free end conditions. An ADXL-335 analog accelerometer was affixed to the bottom of the beam and aligned to the axis of the beam. Students built an Arduino (model of their choice) circuit to collect the accelerometer and time data and relay it to a computer over USB serial connection. The Arduino collects at a non-uniform rate but on average, it sampled at 1800 Hz: over twice the frequency of the first four natural frequencies of the beam.
This paper will detail the introduction of a new laboratory experience in a senior-level Mechanical Engineering Vibrations course. Students are to determine the first four natural frequencies of a 6061 Aluminum free-free beam in a laboratory using three methods. First, they use the idealized theoretical continuous beam model. Second, they use Finite Element Analysis (FEA). Finally, they determine the frequencies experimentally.
Using student survey data, it is shown that the project bolstered the following skills: (1) use of measurement equipment to acquire and transmit real-world data, (2) performing a Discrete Fourier Transform (DFT) and creating the Power Spectral Density (PSD) plot of empirical data, (3) creating and modifying FEA code in MATLAB to find natural frequencies and test for convergence of results and (4) connecting the distinct topics of the course together.
Mahoney, J. M., & Nathan, R. (2017, June), Mechanical Vibrations Modal Analysis Project with Arduinos Paper presented at 2017 ASEE Annual Conference & Exposition, Columbus, Ohio. 10.18260/1-2--28660
ASEE holds the copyright on this document. It may be read by the public free of charge. Authors may archive their work on personal websites or in institutional repositories with the following citation: © 2017 American Society for Engineering Education. Other scholars may excerpt or quote from these materials with the same citation. When excerpting or quoting from Conference Proceedings, authors should, in addition to noting the ASEE copyright, list all the original authors and their institutions and name the host city of the conference. - Last updated April 1, 2015