Investigation of Failure Modes in a Ceramic Composite Under Off-Axis Loading
Abstract
The purpose of this study was to investigate the failure behavior of a ceramic composite (Corning's Nicalon/CAS II) under off-axis loading, and compare the test results with material behavior modeling techniques for polymeric composites. Six different orientations (0, 15, 30, 45, 60, and 90 degrees off axis), with three specimens at each orientation, were tested in an MTS machine. The 60 and 90 degree specimens were tested by gluing them into a fixture that had already been installed into the grips. All others were install in the grips. Thereafter, other specimens were tested incrementally, stopping along the way, to find when and where matrix cracking starts. Acoustic emission was used to determine when cracking starts and replication was used to confirm the cracking. The 0, and 15 degree specimens started cracking in the matrix during the linear portion of the stress-strain curve, at about 35 percent of their ultimate strengths. The rest of the orientations cracked when they reached the ultimate strength. All off-axis load orientations broke parallel to the direction of the fiber, except the 15 degree which was 25 degrees off-axis. The 0 degree specimen showed a decrease in transverse strain before final failure occurred. Theses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA216133
Entities
People
- Walter E. Fink Iii
Organizations
- Air Force Institute of Technology