Micromechanical Evaluation of Ceramic Matrix Composites
Abstract
Analytical and experimental studies have been performed to investigate the thermomechanical properties and failure mechanisms in unidirectional ceramic composites in which the ceramic matrix is flawed and variable. Preliminary model for brittle matrix with a periodic hexagonal array of identical fibers has been analyzed on the basis of numerical fracture mechanics to assess criticality of various kinds of cracks. When this composite model is subjected to axial load, it was found that transverse matrix cracks become unstable for perfect bonding and for disbonding between fibers and matrix, while disbond cracks propagating parallel to the fibers tend to stabilize. The Air Force goal of developing high thrust-to-weight turbine engines depends strongly upon the advancement of high temperature ceramic composites. Ceramic materials retain stiffness at very high temperatures but their extreme brittleness precludes their use as structural materials, since cracks propagate easily and catastrophically. When a ceramic matrix is reinforced with unidirectional fibers the effect of cracks changes fundamentally.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1991
- Accession Number
- ADA236756
Entities
People
- B. W. Rosen
- C. Laird
- C.-f. Yen
- Z. Hashin
- Zhongbao Wang