User`s guide
67
3. PROCEDURES
In order to estimate the internal pressure of soda cans, the procedures of this experiment include research
for relevant data, hardware set-up, construction of LabVIEW program, signal conditioning, taking
measurements, and data analysis. The measurements should be repeated on 3 soda cans.
The information acquired from research and part of the measurement process should also be used to
produce uncertainty analysis and the contribution of each parameter to total uncertainty.
3.1 Preparation
3.1.1 Research for Relevant Parameters
Research for the parameters below, and provide references:
a. Standard dimension of soda cans: diameter and thickness.
b. Material property of soda cans: material type, elastic modulus, and Poisson’s ratio.
c. Common internal pressure range of soda cans.
Document 1 includes relevant data and some information on the materials of soda cans.
3.1.2 Understand the Effects of Gain in the Signal Conditioner
Calculate the amplifier gain required to amplify the output of the Wheatstone bridge so that you get 1
mV/micro-strain.
Recall Gage factor defined in eq.8,
Measured strain can be expressed as
Recall the expression of change in bridge output voltage caused by a small change in resistance from
eq.14,
From eq.15 and eq.14, the relationship between measured strain and change in output can be found as,
Eq.15
Eq.16