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U.S. Department of Energy
Office of Scientific and Technical Information

Literature survey of discontinuous-fiber-reinforced composites with emphasis on pressure vessels

Technical Report ·
OSTI ID:5864806

The critical fiber length (l/sub c/) plays a major role in determining the strength, stiffness (elastic modulus), and toughness (fracture energy) of discontinuous-fiber-reinforced composites. Composite toughness is maximized when the fiber length (l) is approximately equal to l/sub c/, while the strength and stiffness increase rapidly as l goes from l < l/sub c/ to l = l/sub c/ and continue to increase as l increases to 10 l/sub c/. At 10 l/sub c/, discontinuous-fiber-reinforced composites behave similarly to continuous-fiber-reinforced composites. Randomly oriented, discontiuous composites can be formed using techniques such as injection molding or hot press molding. The volume fraction of fibers which these mehtods can tolerate is about 25%, but the ability to use stronger, single crystal, discontinuous fibers (whiskers) would help offset any loss in composite strength. Calculations demonstrate that the tensile strength of the biaxially isotropic composite in any direction (in the random plane) can ideally be comparable to the unidirectional strength of a continuous-fiber-reinforced composite. Randomly oriented discontinuous-fiber-reinforced composites would offer several advantages over continuous-fiber-reinforced composites such as easier fabrication techniques and simplified stress analysis.

Research Organization:
Rockwell International Corp., Golden, CO (USA). Rocky Flats Plant
DOE Contract Number:
AC04-76DP03533
OSTI ID:
5864806
Report Number(s):
RFP-3733; ON: DE85010386
Country of Publication:
United States
Language:
English