Micromechanics analysis of fiber toughening in ceramic-matrix composites. Technical report

Technical Report · Fri Dec 01 04:00:00 EST 1989

OSTI ID:5410264

Balis, C D; Wang, S S

Finite element analysis combined with elasticity results governing fiber pullout is used to investigate toughening of undirectional fiber-reinforced ceramic matrix composites. The most important literature concerned with toughening of refractory fiber-reinforced ceramic matrix composites is reviewed, including both experimental attempts to produce tougher composites and analytical models to predict and describe the toughening mechanisms. The primary toughening mechanisms include crack-bridging, crack-tip/fiber interaction and crack front bowing. Of these, the bridging and interaction, which are idealistically two-dimensional mechanisms, dominant the toughening and control the third bowing mechanism. A two-dimensional elasticity solution governing the fiber pullout mechanics of crack bridging is presented and applied in a two-dimensional finite element toughening model. This model includes both the crack bridging coupled with the crack-tip/fiber interaction mechanisms and is used to investigate the role of various parameters in the composite toughening. In addition, certain stress that govern crack propagation are reported. Investigated parameters included fiber/matrix stiffness ration, interfacial friction coefficient, crack-tip position and remote applied load. It is found that crack bridging is the dominant mechanism and the toughening in the bridge composite is strongly dependent on stiffness ratio, crack tip position and remote applied load.

• Research Organization: National Center for Composite Materials Research, Urbana, IL (United States)
• OSTI ID: 5410264
• Report Number(s): AD-A-233957/0/XAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALLOYS
BRIDGES
CERAMICS
COMPOSITE MATERIALS
CRACK PROPAGATION
CRACKS
CRYSTAL STRUCTURE
ELASTICITY
ELEMENTS
FAILURES
FIBERS
FINITE ELEMENT METHOD
FRACTURE PROPERTIES
FRICTION
INTERFACES
MATERIALS
MATHEMATICAL MODELS
MATRIX MATERIALS
MECHANICAL PROPERTIES
MECHANICAL STRUCTURES
MECHANICS
METALS
MICROSTRUCTURE
NUMERICAL SOLUTION
REFRACTORY METALS
REINFORCED MATERIALS
TENSILE PROPERTIES
YOUNG MODULUS