Characterization of mechanical-damage mechanisms in ceramic and polymeric -matrix composite materials. Technical report, Oct 89-Oct 90
The principal objective of the program has been to establish the loading rate dependence of compressive deformation and fracture mechanisms in whisker and fiber-reinforced ceramic matrix composites, and in fiber-reinforced polymeric matrix composites. Work during the last year has emphasized several types of composite: Silicon Carbide fiber and Silicon Carbide whisker-reinforced pyroceram, and graphite fiber-reinforced thermoplastic. The behavior of a unidirectional carbon fiber-reinforced thermoplastic matrix composite subject to compressive loading at strain rates ranging from 10 to the minus 5 sec t the minus 1 to 5000 sec to the minus 1 is reported. Damage mechanisms are identified, and discussed in terms of matrix microstructure and fiber interactions. In particular, it is found that under quasi-static conditions, two absolutely critical factors control the life of the composite, i.e., the ability of the polymeric matrix to resist shear and thereby inhibit fiber flexure, and the ability of individual fibers to resist the nucleation of compressive plastic shear bands during flexure. It also is shown that at very high rates of strain (approx. 5000/s), the strength suddenly begins to increase with strain rate in an extremely robust fashion. The measured strength-strain rate dependence in this range is shown to be consistent with the kinetics of kink band propagation.
- Research Organization:
- Southwest Research Inst., San Antonio, TX (USA)
- OSTI ID:
- 5690359
- Report Number(s):
- AD-A-230220/6/XAB; CNN: N00014-84-C-0123
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COMPOSITE MATERIALS
MECHANICAL PROPERTIES
CERAMICS
COMPRESSION
CONTROL
DAMAGE
DEFORMATION
FIBERS
FLEXURAL STRENGTH
FRACTURE MECHANICS
GRAPHITE
INTERACTIONS
MATRIX MATERIALS
MICROSTRUCTURE
NUCLEATION
PLASTICS
REINFORCED PLASTICS
SERVICE LIFE
SHEAR PROPERTIES
SILICON CARBIDES
STRAIN RATE
THERMOPLASTICS
CARBIDES
CARBON
CARBON COMPOUNDS
CRYSTAL STRUCTURE
ELEMENTAL MINERALS
ELEMENTS
MATERIALS
MECHANICS
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYMERS
REINFORCED MATERIALS
SILICON COMPOUNDS
SYNTHETIC MATERIALS
360603* - Materials- Properties