This study presents the experimental results that characterize a nastic sheet
material’s performance. We defined nastic sheet as a McKibben muscle designed from a
foundation that would be embedded as an array in an elastomer matrix. The goal is to be
able to utilize the embedded McKibben sheets in the biomedical industry as an
improvement to the synthetic devices and/or processes. One mechanism that might
produce these improvements is to mimic the biological materials that form functional
organs, biological structures, and active tissues. Linking human technology and natural
structures is and will continue to be important to society for several reasons. It would
improve: (1) the lifestyle of humans in regards to artificial parts that mimic human parts
(which will allow us to live longer), (2) artificial limb functionality, and (3) comfort and
aesthetics.
The objective is focused on characterizing and evaluating McKibben muscles as
an embedded muscle sheet by building McKibben muscles and testing them alone and in
sheets with one, two, three, and five muscles. The sheets would be known as a single,
double, triple and quintuple embedded sheet. Another objective is to determine the
performance penalty that embedding puts on the material. The experiments performed used several different approaches, such as analytical
models, tensile test analysis, and prototype construction of the specimens. All
specimens were designed to have a constant final length of 120mm, being embedded in a
polyurethane matrix. We characterized the fundamental performance of a McKibben
muscle and each specific embedded sheet. We measured the specimens’ work-density
and quantified the inactive matrix’s impact on work-density.
Based on the results, several improvements were suggested on the fabrication of the
specimens. The experiment shows positive potential outcome that could be utilized in
the biomedical field, but the results would improve with the suggestions provided in the
study. A sample of the results - the actual work-density for both the single and doubleembedded
sheets showed an increase to 7.82% and 2.96% consecutively. Once the
specimens are removed from the mold, the McKibben muscle automatically tries to
retract to its initial state while the polyurethane matrix tries to stay at its initial state
