Accession Number:

ADA305777

Title:

Space Radiation Effects on Graphite-Epoxy Composite Materials

Descriptive Note:

Interim rept. no. 49

Corporate Author:

VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG COLL OF ENGINEERING

Report Date:

1984-06-01

Pagination or Media Count:

179.0

Abstract:

The objective of this study is to characterize radiation effects or engineering properties, dimensional stability, and chemistry on state-of-the-art composite systems. This investigation used T300934 graphite-epoxy composite that was subjected to 1.0 MeV electron radiation for a total dose of 1.0 x 10 to the 10th rads at a rate of 5.0 x 10 to the 7th radshour. This simulates a worst-case exposure equivalent to 30 years in space. Mechanical testing was performed on the 4-ply unidirectional laminates over the temperature range of -25O deg F 116K to 250 deg F 394K. A complete set of in-plane tensile elastic and strength properties were obtained. In addition electron microscopy was used to study and analyze the fracture surfaces of all specimens tested. Results indicate that little difference in properties is noted at room temperature, but significant differences are observed at both low and elevated temperatures. Dynamic-mechanical analysis showed that the glass transition temperature of the epoxy matrix was lowered by over 100 deg F 56K after being irradiated. Thermomechanical analysis demonstrated that volatile products are produced upon heating the irradiated material. These degradation products were analyzed by infrared spectrophotometry and mass spectrometry, and found to be low molecular weight material produced by polymer chain scission and crosslink breakage. In conclusion, electron radiation acts to produce low molecular weight material in the epoxy resin matrix.

Subject Categories:

  • Astrophysics
  • Laminates and Composite Materials
  • Nuclear Physics and Elementary Particle Physics
  • Unmanned Spacecraft
  • Manned Spacecraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE