User`s guide
74
Document 1: Soda Can Parameters and Uncertainty Estimation as a
Reference
a. Standard dimension of the soda can (diameter and thickness) and the
uncertainties associated
The standard values and factors contributing to uncertainty for can diameter and thickness of a soda can
are listed in table below.
2
Standard
Resolution
Repeatability
(Assumed)
Standard Deviation
(Assumed)
Metric
English
Diameter
6.6 cm
2.6 in
0.001 in
0.005 in
0.0001in
Thickness
0.013cm
0.005in
0.0001 in
0.0001in
negligible
Table 1 Standard values and factors contributing to uncertainty for can diameter and thickness
According to the table above, for diameter, the uncertainty caused by resolution is
,
the uncertainty caused by repeatability is
, uncertainty caused by standard deviation
is
. Therefore, uncertainty in diameter is calculated as:
Similarly, for thickness, the uncertainty caused by resolution is
, the uncertainty
caused by repeatability is
. Therefore, uncertainty in thickness is calculated as:
Same approach can be applied to uncertainty of strain measurement.
Resolution of strain measurements can be extracted by plotting the measurements data points and
identifying the smallest increment.
When gain=192, resolution is 0.325 and uncertainty caused by resolution is 0.325 . Therefore,
repeatability is 0.163, and uncertainty caused by resolution is 0.163 . The strain gauge chosen for
this experiment has a gauge factor of 2.095 0.5%. Therefore, when measuring strain of 1000, the
uncertainty caused by gauge factor is 5.
2
Berlage, R. (2001). Strain Measurements of a Soda Can. Northern Illinois University.
Eq.14
Eq.15
Eq.16