Comparison of Matrix Cracking in High Temperature and Lower Temperature PMCs from Cryogenic Exposure (Preprint)
Abstract
The behavior of a high temperature carbon/polyimide composite, T650/AFR-PE-4, in a cryogenic environment was studied. The results were compared to results from similar testing of a carbon/epoxy and a carbon/bismaleimide composite to begin to scale the difficulties involved with using high temperature polymer matrix composites (PMCs) in cryogen containers on launch vehicles. T650/AFR-PE-4 developed transverse cracks in all plies after fewer cycles than the carbon/bismaleimide (IM7/5250-4) when each was cycled between -196?C and their respective maximum service temperatures. While a change to a cross-ply of IM7/5250-4 showed a substantial reduction in the tendency toward a complete crack network in past work on IM7/5250-4, there was only a small delay of 50 cycles in the formation of transverse cracks in all plies when a [0/90]2S lay-up of T650/AFR-PE-4 was used instead of a [0/45/-45/90]S lay-up. On the other hand, the lay-up change corresponded to a large permeability reduction indicating that either the amount of delamination was much lower in the [0/90]2S samples after thermal cycling or the cracks did not extend far from the sample edges. Basic composite properties ? transverse strength and mode I toughness of unidirectional laminates ? were also measured at room temperature and -196?C to further determine the sources of the rise in damage accumulation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2007
- Accession Number
- ADA473959
Entities
People
- Vernon T. Bechel
Organizations
- Air Force Research Laboratory