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Undergraduate Research at UMass Dartmouth
to deform as desired, but the sample begins to slip
in the middle of testing. A successful tensile testing
graph would look more like Figure 7. This graph was
the result of one of the practice tests; however, the
sample broke right at the bottom grip (displayed in
Figure 8), which is not desirable. The sample should
break more toward the center of the gage length.
Breaking at the grips occurs due to improper stress
concentrations through the sample; the grips are
exerting too much force on the sample and weakening
it at the grip points. Various materials such
as sandpaper and rubber were used to try to create
more friction between the sample and the grips
without applying too much force, but these attempts
were not successful.
The research grant provided to me by the Office of
Undergraduate Research allowed me to obtain many
necessary materials including the plants and the
various materials needed to care for them. While
no conclusive measurements have been collected,
these funds and materials provided me the opportunity
to conduct valuable troubleshooting for
this project. I would not have been able to pursue
researching this unique application of mechanical
engineering without the support of the grant. I would
like to acknowledge my advisor Dr. Tracie Ferreira for
her support and guidance with this project.
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An alternative idea for tensile testing has been
investigated but not yet tested. It involves wrapping
the ends of the stem sample around hooks instead
of compressing the ends in grips. This is a method
commonly used for testing the tensile strength of
string samples. This set-up does not have all the
necessary components, but the available components
have been gathered as seen in Figure 9. There
may be some need for manufacturing in order to
complete the testing set up. This will be explored
further during the fall 2018 semester.
The current plans for the continuation of this project
consist of obtaining and maintaining a new set of
plants over the summer months in order to establish
a healthier set of samples. Measurements from this
healthier set of plants will be collected in the fall
2018 semester.
Figure 4. Two basil stem cross sections stained with toluidine blue
and examined under a microscope