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Predicted Effects of Interfacial Roughness on the Behavior of Selected Ceramic Composites
Author(s) -
Parthasarathy Triplicane A.,
Kerans Ronald J.
Publication year - 1997
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1997.tb03088.x
Subject(s) - materials science , composite material , composite number , fiber , volume fraction , surface finish , surface roughness , ceramic , ceramic matrix composite
Potential effects of interfacial roughness in ceramic composites were studied using a model that included the progressively increasing contribution of roughness with relative fiber/matrix displacement during debonding of the fiber/matrix interface. A parametric approach was used to study interfacial roughness in conjunction with other parameters such as the strength, radius, and volume fraction of the fiber. The progressive roughness contribution during initial fiber/matrix sliding caused a high effective coefficient of friction, as well as an increased clamping stress, which led to rapidly changing friction with increasing debond length. Calculated effects implied a potentially significant contribution to the behavior of real composite systems and the necessity for explicit consideration in the interpretation of experimental data to understand composite behavior correctly. In a tension test, the Poisson's contraction of the fiber may negate the effects of roughness, allowing an “effective constant shear stress” (tau) approximation. This was evaluated using a piecewise linear approximation to the progressive roughness model in an analysis of composite stress‐strain behavior; for the Nicalon/SiC system, the effective tau value was lower than the values that would be obtained from fiber pushout tests and/or matrix crack spacings.