Olafbc

https://www.canva.com/design/DAEruulo13Y/6KZE_ATLqRhBcse5tzek-A/view?utm_content=DAEruulo13Y&utm_campaign=designshare&utm_medium=link&utm_source=sharebutton

https://drive.google.com/drive/folders/18tcSNUG3eW8JJtUKxpCZdkZyzTXQlinI?usp=sharing

Electroactive Polymers

Electroactive polymers consist of materials that have a mechanical response to an electrical stimulus. Among them, there is a division between two categories, electronic and ionic.

Electronics are those activated by the Coulomb force, which causes a reduction in thickness or a dimensional change (due to internal polarization, with molecular alignment). Furthermore, a high voltage is factors (greater than 10 V µm-1) and its response time is fast, reaching up to milliseconds, this due to its activation by an electric field. Some examples of them are dielectric, piezoelectric, and ferroelectric elastomers.

The second type is activated through the mobility of ions in electrical excitation, so it is necessary to use electrodes and electrolytes. They act at a low activation voltage (1-2 V) and generate large bending displacements. Some examples of them are ionomeric polymer-metal composites, conductive polymers, carbon nanotubes, and ionic polymer gels.

For the current project, the use of EAPs in the electronic category is interesting, due to their fast response time to electrical current, a necessary characteristic for cutting the reef line. Among the materials in this category, the type selected was the dielectric elastomer, which has thinning properties.

Implementation

• Spring system: To provide the necessary speed and force to the blades for cutting the reefing line, there is the use of a compressed spring system at the ends of the device. When released, the springs stretch and propel the blades. There are also two more springs to eject both the rail and the pin. These two springs will be better explained below.

• Pin ejection: In order to release the first spring and cut the rope at the right time, the first spring is maintained compressed by a pin. This pin enters a circular hole and is kept still by a base. This base is a rail system attached to a spring and the EAP system keeps it from moving.

• EAP System: Responsible for releasing the spring actuation. This system consists of an electroactive polymer barrier. As explained above, certain kinds of EAP materials contract in one of their axis when an electric field is generated inside it. Therefore, this material can act as a temporary barrier and, when needed, release the rail system, pin, and blade.

Conclusion

The team developed a system that aims to cut the reefing line. It is composed of a blade that will be actuated by a spring mechanism, which is retracted by a valve controlled by an electroactive polymer, more specifically a dielectric elastomer. At the time of activation, an electric current will pass through the polymer which, in turn, will expand, decreasing its height and lowering the valve. Consequently, the spring that was stuck will be released and will tend to return to its position, pushing the blade forward.

The benefits brought by this system are greater reliability and stability, a greater potential for the development of EAP materials, in addition to a smaller number of safety protocols, it is reusable, does not require pyrotechnics, does not release debris, and is fast in its execution. The team hopes to help revolutionize NASA's mechanical systems, expand aerospace expertise, develop system prototypes, and encourage the use of EAP technologies. The team used only SolidWorks for CAD development.

To carry out the project, all members read the materials available on the challenge website. The data that most caught everyone's attention were those shown in the reefing line's cutting documents. In addition, we are looking for new technology, and for that, we use a document from the Jet Propulsion Laboratory (Electroactive Polymers (EAP) as Actuators for Aerospace Engineering). Therefore, it can be noted that we only use NASA's database, both for inspiration and theoretical background.

• Participating in the NASA Space Apps Challenge provided a unique experience, bringing the challenge of designing something in a short period. This enabled the team to mature exponentially about project organization, going through stages of brainstorming, goal setting, schedule, tradeoffs, and technical development.
• It was possible to acquire and improve technical knowledge about the recovery phases of a rocket, EAP materials technology, and stages of a project under pressure.
• Our team consists of Aerospace Engineering students, which sparked interest in applying the knowledge seen in classrooms through a challenge of creativity and engineering. Also, being on a NASA-sponsored challenge excited the team.
• Development of new technologies, simply and functionally.
• In situations of setbacks and challenges, a general meeting was held with the team members to identify the problem and outline a solution strategy.
• We would like to thank the initiative of NASA and the Brazilian Space Agency for providing us with this experience of an engineering aerospace project.

1. Bashir M, Rajendran P. A review on electroactive polymers development for aerospace applications. Journal of Intelligent Material Systems and Structures. 2018;29(19):3681-3695. doi:10.1177/1045389X18798951
2. https://pressbooks.bccampus.ca/practicalphysicsphys1104/chapter/4-2-hookes-law-originally-section-5-3-elasticity-stress-and-strain/
3. BAR‐COHEN, Yoseph. Electroactive polymers (eap) as actuators for aerospace engineering. Encyclopedia of Aerospace Engineering, 2010.
4. https://www.maxwell.vrac.puc-rio.br/11510/11510_4.PDF
5. https://www.hq.nasa.gov/alsj/CSM12_Earth_Landing_Subsystem_pp93-98.pdf
6. https://www.nasa.gov/mission_pages/constellation/ares/parachute_results.html
7. https://spinoff.nasa.gov/Spinoff2020/ip_8.html
8. https://ntrs.nasa.gov/api/citations/20110016488/downloads/20110016488.pdf
9. https://trs.jpl.nasa.gov/bitstream/handle/2014/45484/14-0701_A1b.pdf?sequence=1

#EAP, #Guillotine, #CigarCutter, #ReefingLineCutter

This project has been submitted for consideration during the Judging process.