Synopsis of the Strain Energy Accumulator Research

Hello all!

This summer has gone by too quickly, but it has been an awesome ride here in Nashville. As a research team, we have grown closer together as friends, as well as make ample progress to our goals for the summer. They have been great to work with and are some of the sharpest tools in the shed!

Research Results

The purpose of my research this summer, was to prove that conductive elastomers can successfully be used to monitor damage inflicted upon them. The material that is in development for use in the Strain Energy Accumulator will need to successfully determine if critical damage has been inflicted. To prove this, we tested an on-the-market conductive elastomer. The following tests were performed:
           

  1) Damage Infliction -- we purposefully scratched and cut the material to measure resistance    changes. The results formulated gave us insight into how the material shows promising directional sensing abilities. This is shown especially with the vertical abrasion, which permanently eliminated conductance in the material. 

          2) Tensile Test -- a test rig was configured to observe how the resistance changes with increasing load, as well as the hysteresis and Mullens effects of the elastomer. This test yielded repeatable results and really gave me insight into how conductive elastomers will actually react in an application

This research successfully proved that elastomers can be used practically when sensing applications are necessary! Though the research did give our team a proof-of-concept, the material tested has many shortcomings for our application including: deficient durability, single sided conductance (conductance only on surface level of the elastomer), and conductance at only small strains (< 100%).

Future Work

A couple of trials are going to be done with this conductive material. The research team will adhere a rectangular specimen to the current Strain Energy Accumulator design, with attached leads to monitor resistance changes through out charge and discharge. Secondly, a specimen will be glued to a elastomeric sample during tensile testing on an MTS machine. Each of these experiments will gives us insight into the reactions that can be expected in practical applications. Here is a picture of our accumulator that was made this summer:

   

This polypropylene tube is filled with hydraulic fluid and begins to balloon, much like an animal ballon. The energy is stored in the strain of the elastomeric material and can be harvested during discharge.

Closing

I would like to thank the CCEFP, Dr. Adams, Dr. Barth, and the rest of my research team for giving me the resources that I needed to complete my research this summer! The experience for myself was wonderful and is something that I will take with me through out my life and career. Living in Nashville has been a blessing, and I have met some amazingly talented and respectable people along the way. Again, thanks for everything. I look forward to seeing all of my fellow REU's in our future careers, and I hope to stay in contact.