Self recoverable structure : material
Tay, Zhen Yao.
Date of Issue2009
School of Mechanical and Aerospace Engineering
During space travel, spacecraft may bum into objects that are orbiting in space. Therefore a ‘spacecraft bumper’, similar device like a car bumper is needed to protect the hull surface of the space ship. Damage to spacecraft due to ‘wear-and-tear’ where extremes of environment can cause small damages to open up in the superstructure, as impact by meteoroids traveling at remarkable speeds of several kilometers per second. Cracks will grow underneath the surface of the material which is invisible to the naked eye. Over lifetime of the mission these cracks build up, weakening the spacecraft until a catastrophic failure becomes inevitable . While "self-inflating" devices aren't new to the market especially in the commercial industry, most of the existing systems utilize compressed air to inflate or maintain pressure. This is especially true for car tires. However Coda's "SIT" system uses a peristaltic pump built directly into the tire that uses the spinning wheel to force air through a liquid-filled tube to maintain pressure compensating the loss of pressure. This ensures maintenance-free and constant tire pressure over the lifetime of the tire. We explore the use of chemical reaction that able to generate sufficient gas, making use of the air pressure to further strengthen the ‘spacecraft bumper’ during crashing but at the same time recovering to its original form. Behaving like a self inflated airbags in cars during collisions. High temperature in space may also affects the rate of reaction, thus posing as a crucial factor in the sensitivity of the material which is important for the material to restore itself where few seconds differences could mean life and death . The primary research was to fabricate a material capable of recovering to its original shape and size upon impact. The material uses Sylgard 184 silicone as the matrix and the concept of microcapsules embedded in the matrix capable of releasing significant air pressure upon breaking, forcing the material to restore to its original form. The secondary research was carrying out experiments to test out the feasibility of the design concept in extreme conditions, for example heating the specimen. To design structural elastic prototype in a larger scale which is able to absorb impact and resume its original shape without any repercussions. Lastly this report only attempt to demonstrate the possibility of a self recoverable material/structure at preliminary stages which can be fabricated using simple lab technologies.
Final Year Project (FYP)
Nanyang Technological University