Micromechanics Analysis of Fiber Toughening in Ceramic-Matrix Composites
Abstract
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA233957
Entities
People
- C. D. Balis
- S. S. Wang