Time-dependent micro mechanics in damaged high-temperature ceramic composites
- Univ. of California, Los Angeles, CA (United States)
Under monotonic loading of unidirectional ceramic-matrix composites, it has been observed that periodic matrix cracking takes place if the matrix strain-to-failure is below that of the fibers. Furthermore, it has been found that interface debonding, frictional slip and the subsequent bridging of matrix cracks control the overall response of this class of materials. At elevated temperatures, however, fiber and/or matrix creep is expected to dominate the micro mechanical behavior and, in turn, the macroscopic deformation response of the composite. In this paper, a micro mechanical model is developed to study the effects of fiber creep on fiber-matrix interface debonding and fiber frictional slip. The model is particular to composite systems whose fibers exhibit much faster creep rates in comparison with matrices. The model is applied to predict the creep response of composites loaded beyond the matrix cracking stress. It is found that the macroscopic creep response is characterized by a secondary creep regime which is associated with slow propagation of interface debonding cracks, followed by a tertiary creep regime during which rapid growth of debonding represents an instability mechanism.
- OSTI ID:
- 175295
- Report Number(s):
- CONF-950686-; TRN: 95:006111-0252
- Resource Relation:
- Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
- Country of Publication:
- United States
- Language:
- English
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