User`s guide

43
Experimental Procedures
In order to understand the errors in this experiment, the procedure is repeated on two
similar cantilever beams.
Preparation
Find the elastic modulus and density of the material used for the cantilever beams.
LabVIEW Program
The constructed LabVIEW program obtains amplified voltage output and transfers the
output to strain, with the unit of micro-strain. A spectral analyzer performs Fourier
Transformation on measured strains. Measurement results in both time domain and frequency
domains are then recorded. A sampling rate of 5k S/s is selected, and 5 seconds of data is
recorded in each reading.
Hardware Setup
A strain gauge is installed onto each of the three soda cans used in this experiment.
Measure the diameter of the soda can.
The strain gauge is installed on the soda can surface along the circumferential direction,
the height of the strain gauge location should be half of the can height.
The strain gauge is connected to the quarter bridge completion circuit. A Tacuna Systems
Strain Gauge or Load Cell Amplifier/Conditioner Interface Manual (Tacuna) is used to supply
excitation voltage and amplify the signal. Gain is set at 220, while the excitation is set at 5 VDC.
The settings are verified by checking the switches on the circuit board. The wire connections are
indicated in Figure 1.
Figure 10 Connections for Tacuna Systems Strain Gauge or Load Cell Amplifier/Conditioner Interface Manual