bobvibratingbeam - VIBRATING BEAM NATURAL FREQUENCY AND...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
VIBRATING BEAM NATURAL FREQUENCY AND DAMPING Robert J. Lichtenthal III Matt Adamchick Drew Mahoney October 8, 2007 Section 11 Abstract: In order to study the response of a beam, two testing techniques were used. Three types of metal samples were tested: Plain Carbon Steel, 2012-T6 Aluminum, and Cartridge Brass. A shaker table was used to demonstrate the effects of natural frequency on a steel beam. An estimate for the beam’s natural frequency was obtained from the graph of the collected data. A hammer-strike induced vibration was analyzed for each material. The stiffness of each material was calculated using both graphical data and strengths of materials equations. Obtaining the peaks of a harmonically oscillating data set was done with two methods. For the smooth curve produced by the steel and the brass samples, slope differences were used to calculate the peaks. For the fuzzy curve produced by the aluminum sample, the user picked the peaks from the graph. The values from the graph and the equations were close, but demonstrate the differences between experimental and theoretical data. It was found that an increase in mass of the beam increased natural frequency. A trend for mass and damping coefficient was not evident as shown in following graphs. Error was analyzed and propagated to take into account the limited accuracy of the measurands.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Task One : Plot Shaker Table Data for the Steel Beam For the first half of this experiment, a shaker table apparatus was used to observe the affects of an item’s natural frequency. The shaker table allowed a beam to be vibrated at various frequencies. An accelerometer attached to a steel beam was used to record data in the form of applied frequency, and the corresponding amplitude in volts. For the TA run trial, the data for the steel beam can be seen below in Table 1.1: Table 1.1 Frequency (Hz) Amplitude (volts) 15.8 0.01184 21.9 0.02568 28 0.05809 31.7 0.09522 35.4 0.1374 39 0.3769 41.5 0.5522 42.7 0.5013 45.1 0.5507 47.6 0.5104 52.4 0.3077 A graph was generated from this table in MATLAB (1) and can be seen in Figure 1.1 below:
Background image of page 2
Figure 1.1 15 20 25 30 35 40 45 50 55 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Shaker Table Data Frequency (Hz) Amplitude (volts) Recorded Data Points Shape-Preserving Interpolant Estimated Natural Frequency The asterisk (*) on Figure 1.1 is an indicator of the estimated natural frequency which is 43 Hz. By observing that the data points were taken at intervals of approximately 3 Hz, the error interval could be estimated at +/- 1.5 Hz.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Task 2 : Calculating K Values For the second part of the experiment, frequency and amplitude data was recorded for steel, aluminum, and brass under a hammer-strike induced oscillation. An accelerometer coupled with a Labview DAQ (2) recorded the data which was processed with MATLAB. In order to compare the responses of the three materials, it will be useful
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/09/2008 for the course ME/AE 301 taught by Professor Lafleur during the Spring '08 term at Clarkson University .

Page1 / 12

bobvibratingbeam - VIBRATING BEAM NATURAL FREQUENCY AND...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online