Energy absorption behavior of Spacecraft Carbon-epoxy composite wall at oblique angle for hypervelocity impacts in low Earth orbit environment
- Paper number
IAC-11,A6,3,18,x11688
- Author
Mr. Abrar-Ul-Haq Khan Baluch, Korea Advanced Institute of Science and Technology (KAIST), Korea, Republic of
- Coauthor
Prof. Chun Gon Kim, Korea Advanced Institute of Science and Technology (KAIST), Korea, Republic of
- Year
2011
- Abstract
Hypervelocity impacts (HVI) of space debris lead to the destruction of spacecraft subsystem functionality and sometimes spacecraft itself.This is more devastating especially in LEO environment.Till date only 6\% population of LEO are operational spacecraft,while rest are more or less lie in the category of space junk.Approximately 19,000objects are greater the 10cm,while in between 1to10cm diameter objects population is around 500,000 in numbers with major concentrations around 800-850km.Evidence from the experimental study of space debris by NASA shows the impacts of debris on the spacecraft are only 10~20\%normal to the surface while rest are at oblique angles.Till date,different shielding concepts has been adopted and tested ranging from simple whipple shield to mesh double bumper shield but all those includes metal composition along with Kevlar&Nextel.But the potential of Carbon-epoxy composites being less in weight and better in strength then Aluminium still has to be exploited.In this research,the first part of Hybrid composite shielding(HCS),carbon-epoxy behavior is tested and validated for oblique angle.First of all carbon-epoxy laminate is being made by using CU-125NS with 16layers,1.748mm thick[(0,±45,90)2]s,as its been found the best among all the other commercially available prepreg for space applications.After manufacturing of composite,the specimen is subjected to LEO environment simulation chamber for 14thermal cycling and allowed to be attacked by atomic oxygen to get the proper LEO environment.In the end,two stage light gas gun(LGG),using Helium and Neon gas, facility is used to get the experimental profile,energy absorption and behavior of composite.In this, the angles of attack were kept oblique by keeping the plate at inclined angel with respect to Aluminum(Al 2017) projectile(debris)5.56mm in diameter.For HVI testing of the structure,the philosophy adopted is the same as done for ballistic limit.The specimen were tested under velocity range of 1km/sec and then validated by commercially available LS-DYNAsoftware.However,the debris velocity range in low Earth orbit region is higher than this.The reference used here is the ballistic limit curve for Whipple shield.The results for impacts at normal angle of projectile are then compared with the oblique angle findings.Electron microscopic image shows how the fibres of laminate get damaged by oblique angles.The expected outcome,is the less absorption of energy with the possibility of deflection depending on the angle of attack.In the end, the comparison is made with oblique, normal and for Aluminium sheet cases.The results show the dominancy of carbon-epoxy composite towards impact handling at oblique angles with itself at normal angles and with Aluminuim alloy.
- Abstract document
- Manuscript document
(absent)