The Influence of Heat Treatment upon Fiber Pull-Out in a Ceramic Composite

1988 ◽  
Vol 120 ◽  
Author(s):  
M. D. Thouless ◽  
O. Sbaizero ◽  
E. Bischoff ◽  
E. Y. Luh
Keyword(s):  
Ceramic Composite ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Shear Lag ◽  
Weibull Statistics ◽  
Pull Out ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

AbstractThe toughness of ceramic-matrix composites is strongly influenced by fiber pull-out. The extent of the pull-out depends upon the properties of the fiber and the fiber/matrix interface. Samples of a SiC/LAS composite were subjected to different heat treatments in order to systematically vary these properties. The predicted distribution of the fiber pull-out lengths was calculated by combining a shear lag analysis with Weibull statistics for the fiber strengths. Comparison of the analysis with experiments and microstructural observations contribute to an understanding of the role of the fiber/matrix interface upon the mechanical properties.

Damping in Unidirectional and Cross-Ply Ceramic Matrix Composites With Matrix Cracks

2001 ◽  
Author(s):  
Victor Birman ◽  
Larry W. Byrd
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Friction ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Unidirectional Composites ◽  
Matrix Cracks ◽  
Dissipation Of Energy ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Abstract The paper elucidates the methods of estimating damping in ceramic matrix composites (CMC) with matrix cracks. Unidirectional composites with bridging matrix cracks and cross-ply laminates with tunneling cracks in transverse layers and bridging cracks in longitudinal layers are considered. It is shown that bridging matrix cracks may dramatically increase damping in unidirectional CMC due to a dissipation of energy along damaged sections of the fiber-matrix interface (interfacial friction). Such friction is absent in the case of tunneling cracks in transverse layers of cross-ply laminates where the changes in damping due to a degradation of the stiffness remain small. However, damping in cross-ply laminates abruptly increases if bridging cracks appear in the longitudinal layers.

Evaluation of Mechanical Properties and Comprehensive Modeling of CMC with Stiff and Weak Matrices

2006 ◽  
Vol 45 ◽  
pp. 1435-1443 ◽  
Author(s):  
Dietmar Koch ◽  
Kamen Tushtev ◽  
Jürgen Horvath ◽  
Ralf Knoche ◽  
Georg Grathwohl
Keyword(s):  
Mechanical Properties ◽  
Mechanical Response ◽  
Ceramic Matrix Composites ◽  
High Strength ◽  
Shear Mode ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Strain Behavior ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

The mechanical properties of ceramic matrix composites (CMC) depend on the individual properties of fibers and matrix, the fiber-matrix interface, the microstructure and the orientation of the fibers. The fiber-matrix interface of ceramics with stiff matrices (e.g. CVI-derived SiC/SiC) must be weak enough to allow crack deflection and debonding in order to achieve excellent strength and strain to failure (weak interface composites WIC). This micromechanical behavior has been intensively investigated during the last 20 years. With the development of CMC with weak matrices (weak matrix composites WMC) as e.g. oxide/oxide composites or polymer derived CMC the mechanical response can not be explained anymore by these models as other microstructural mechanisms occur. If the fibers are oriented in loading direction in a tensile test the WMC behave almost linear elastic up to failure and show a high strength. Under shear mode or if the fibers are oriented off axis a significant quasiplastic stress-strain behavior occurs with high strain to failure and low strength. This complex mechanical behavior of WMC will be explained using a finite element (FE) approach. The micromechanical as well as the FE models will be validated and attributed to the different manufacturing routes.

scholarly journals Effect of Cyclic Fatigue Loading on Matrix Multiple Fracture of Fiber-Reinforced Ceramic-Matrix Composites

Ceramics ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 327-346 ◽  
Author(s):  
Longbiao Li
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Matrix Cracking ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Multiple Fracture ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

In this paper, the effect of cyclic fatigue loading on matrix multiple fracture of fiber-reinforced ceramic-matrix composites (CMCs) is investigated using the critical matrix strain energy (CMSE) criterion. The relationships between multiple matrix cracking, cyclic fatigue peak stress, fiber/matrix interface wear, and debonding are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, and applied cycle number on matrix multiple fracture and fiber/matrix interface debonding and interface wear are discussed. Comparisons of multiple matrix cracking with/without cyclic fatigue loading are analyzed. The experimental matrix cracking of unidirectional SiC/CAS, SiC/SiC, SiC/Borosilicate, and mini-SiC/SiC composites with/without cyclic fatigue loading are predicted.

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