Designing Interfaces in Inorganic Matrix Composites

MRS Bulletin ◽  
1991 ◽  
Vol 16 (4) ◽  
pp. 32-38 ◽  
Author(s):  
James A. Cornie ◽  
Ali S. Argon ◽  
Vijay Gupta
Keyword(s):  
Ceramic Matrix Composites ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Stress Concentrations ◽  
Interface Shear ◽  
Pull Out ◽  
Reinforcing Fibers ◽  
The Matrix ◽  
Definition Of ◽  
Work Of Fracture

The key to controlling and predicting the properties of metal matrix composites lies in understanding and controlling the interface. When properly designed, the interface between reinforcing fibers and the matrix or protective coating can act as a mechanical fuse through a controlled delamination mechanism.Controlled delamination, in effect, results in the decoupling of fibers from early damage due to stress concentrations in the vicinity. The delamination event must precede the crack bridging and frictional pull-out mechanisms that have been so effectively demonstrated in ceramic matrix composites. The delamination event, therefore, is the necessary precondition, and so analysis of composite toughening must start with a definition of the conditions for interface debonding.This decoupling can be expressed in terms of cohesive strength of the interface, shear strength of the interface, and fiber fracture stress. In a related but alternative manner, debonding can be expressed in terms of the intrinsic work of fracture of the interface as compared to the transverse work of fracture of the fiber.

Modeling matrix fracture in fiber-reinforced ceramic-matrix composites with different fiber preforms

2019 ◽  
Vol 90 (7-8) ◽  
pp. 909-924 ◽  
Author(s):  
Longbiao Li
Keyword(s):  
Elastic Modulus ◽  
Ceramic Matrix Composites ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Multiple Fracture ◽  
Fiber Volume ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
The Matrix ◽  
Fiber Preforms

In this paper, the stress-dependent matrix multiple fracture in silicon carbide fiber-reinforced ceramic-matrix composites with different fiber preforms is investigated. The critical matrix strain energy criterion is used to determine the matrix multiple fracture considering the interface debonding. The effects of the fiber radius, fiber elastic modulus, matrix elastic modulus, fiber volume, interface shear stress, and interface debonded energy on the matrix multiple fracture and the interface debonding are analyzed. The experimental matrix multiple cracking and interface debonding of minicomposite, unidirectional, and two-dimensional woven SiC/SiC composites with different fiber volumes and interphases are predicted. The matrix cracking density increases with the increasing of the fiber volume, fiber elastic modulus, interface shear stress, and interface debonded energy, and the decreasing of the fiber radius and matrix elastic modulus.

Estimate interface frictional coefficient of ceramic matrix composites from hysteresis loops

2010 ◽  
Vol 45 (9) ◽  
pp. 989-1006 ◽  
Author(s):  
Longbiao Li ◽  
Yingdong Song
Keyword(s):  
Frictional Coefficient ◽  
Hysteresis Loops ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Fatigue Loading ◽  
Hysteresis Loss ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Interface Shear ◽  
The Matrix

An approach to estimate fiber/matrix interface frictional coefficient of ceramic matrix composites under fatigue loading is developed by means of hysteresis loops. The Coulomb friction law is adopted to describe the interface shear stress in the debonded region. The matrix crack space and interface debonded length are obtained by matrix statistical cracking model and fracture mechanics interface debonding criterion. The hysteresis loops of four different cases are derived based on the damage mechanisms of fiber sliding relative to matrix in the debonded region during unloading and subsequent reloading. The hysteresis loss energy corresponding to different cycle is formulated in terms of interface frictional coefficient. By comparing the experimental hysteresis loss energy with computational values, the interface frictional coefficient of three different ceramic matrix composites under fatigue loading is derived.

Effect of temperature on matrix multicracking evolution of C/SiC fiber-reinforced ceramic-matrix composites

2020 ◽  
Vol 39 (1) ◽  
pp. 189-199
Author(s):  
Longbiao Li
Keyword(s):  
Strain Energy ◽  
Ceramic Matrix Composites ◽  
Critical Value ◽  
Matrix Cracking ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Temperature Dependent ◽  
Damage State ◽  
The Matrix ◽  
Sic Composites

AbstractIn this paper, the temperature-dependent matrix multicracking evolution of carbon-fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) is investigated. The temperature-dependent composite microstress field is obtained by combining the shear-lag model and temperature-dependent material properties and damage models. The critical matrix strain energy criterion assumes that the strain energy in the matrix has a critical value. With increasing applied stress, when the matrix strain energy is higher than the critical value, more matrix cracks and interface debonding occur to dissipate the additional energy. Based on the composite damage state, the temperature-dependent matrix strain energy and its critical value are obtained. The relationships among applied stress, matrix cracking state, interface damage state, and environmental temperature are established. The effects of interfacial properties, material properties, and environmental temperature on temperature-dependent matrix multiple fracture evolution of C/SiC composites are analyzed. The experimental evolution of matrix multiple fracture and fraction of the interface debonding of C/SiC composites at elevated temperatures are predicted. When the interface shear stress increases, the debonding resistance at the interface increases, leading to the decrease of the debonding fraction at the interface, and the stress transfer capacity between the fiber and the matrix increases, leading to the higher first matrix cracking stress, saturation matrix cracking stress, and saturation matrix cracking density.

scholarly journals Micromechanical Modeling Tensile and Fatigue Behavior of Fiber-Reinforced Ceramic-Matrix Composites Considering Matrix Fragmentation and Closure

2021 ◽  
Vol 5 (7) ◽  
pp. 187
Author(s):  
Longbiao Li
Keyword(s):  
Fatigue Behavior ◽  
Constitutive Models ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Fatigue Loading ◽  
Micromechanical Modeling ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
The Matrix

In this paper, micromechanical constitutive models are developed to predict the tensile and fatigue behavior of fiber-reinforced ceramic-matrix composites (CMCs) considering matrix fragmentation and closure. Damage models of matrix fragmentation, interface debonding, and fiber’s failure are considered in the micromechanical analysis of tensile response, and the matrix fragmentation closure, interface debonding and repeated sliding are considered in the hysteresis response. Relationships between the matrix fragmentation and closure, tensile and fatigue response, and interface debonding and fiber’s failure are established. Experimental matrix fragmentation density, tensile curves, and fatigue hysteresis loops of mini, unidirectional, cross-ply, and 2D plain-woven SiC/SiC composites are predicted using the developed constitutive models. Matrix fragmentation density changes with increasing or decreasing applied stress, which affects the nonlinear strain of SiC/SiC composite under tensile loading, and the interface debonding and sliding range of SiC/SiC composite under fatigue loading.

Micromechanical Modeling for Fatigue Hysteresis Loops of Fiber-Reinforced Ceramic–Matrix Composites Under Multiple Loading Stress Levels

2015 ◽  
Vol 07 (06) ◽  
pp. 1550087 ◽  
Author(s):  
Longbiao Li
Keyword(s):  
Slip Length ◽  
Hysteresis Loops ◽  
Ceramic Matrix Composites ◽  
Peak Stress ◽  
Interface Debonding ◽  
Matrix Composites ◽  
Interface Shear ◽  
Interface Shear Stress ◽  
Stress Levels ◽  
Multiple Loading

In this paper, the fatigue hysteresis loops of fiber-reinforced ceramic–matrix composites (CMCs) under multiple loading stress levels considering interface wear have been investigated using micromechanics approach. Under fatigue loading, fiber/matrix interface shear stress decreases with the increase of cycle number due to interface wear. Upon increasing of fatigue peak stress, the interface debonded length would propagate along the fiber/matrix interface. The difference of interface shear stress existing in the new and original debonded region would affect interface debonding and interface frictional slipping between fibers and matrix. Based on the fatigue damage mechanism of fiber slipping relative to matrix in the interface debonded region upon unloading and subsequent reloading, the interface debonded length, unloading interface counter-slip length and reloading interface new-slip length are determined by fracture mechanics approach. The fatigue hysteresis loop models under multiple peak stress levels have been developed. The effects of fiber volume fraction, fatigue peak stress, matrix crack spacing, interface debonding and interface wear on interface slip and fatigue hysteresis loops have been analyzed.

Metal-Reinforced Ceramic Composites for Turbine Vanes

1972 ◽  
Author(s):  
S. A. Bortz
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Metal Fiber ◽  
Turbine Engine ◽  
Turbine Vanes ◽  
The Matrix ◽  
The Relationship ◽  
Structural Matrix

Experiments have been performed which indicate the potential of metal-fiber reinforced-ceramic matrix composites for use as a high temperature structural matrix. The results of this work reveal that metal-fiber reinforced ceramics obey compostie theory, and that after cracks occur in the matrix, a pseudo-ductility can be introduced into the composite. This toughness can be predicted from equations of work required to pull the fibers through the matrix. The relationship between strength, toughness, and crack depths, are dependent on the inter-facial bond between the fibers and matrix as well as fiber diameter and length. Based on the results of these experiments, multicomponent materials with superior resistance to failure from oxidation, thermal shock, and high mechanical stresses in air above 2400 F can be postulated. These materials have potential for use as gas turbine engine vanes.

scholarly journals Mechanical Behavior of Fiber-Reinforced SiC/RBSN Ceramic Matrix Composites: Theory and Experiment

1993 ◽  
Vol 115 (1) ◽  
pp. 91-102 ◽  
Author(s):  
A. Chulya ◽  
J. P. Gyekenyesi ◽  
R. T. Bhatt
Keyword(s):  
Mechanical Behavior ◽  
Ceramic Matrix Composites ◽  
In Situ Monitoring ◽  
Matrix Cracking ◽  
Test Problems ◽  
Interface Debonding ◽  
Failure Behavior ◽  
Fiber Reinforced ◽  
History Effects ◽  
Pull Out

The mechanical behavior of continuous fiber-reinforced SiC/RBSN composites with various fiber contents is evaluated. Both catastrophic and noncatastrophic failures are observed in tensile specimens. Damage and failure mechanisms are identified via in-situ monitoring using NDE techniques throughout the loading history. Effects of fiber/matrix interface debonding (splitting) parallel to the fibers are discussed. Statistical failure behavior of fibers is also observed, especially when the interface is weak. Micromechanical models incorporating residual stresses to calculate the critical matrix cracking strength, ultimate strength, and work of pull-out are reviewed and used to predict composite response. For selected test problems, experimental measurements are compared to analytic predictions.

scholarly journals Localization due to Damage in Two-Direction Fiber-Reinforced Composites

1996 ◽  
Vol 63 (2) ◽  
pp. 321-326 ◽  
Author(s):  
F. Hild ◽  
P.-L. Larsson ◽  
F. A. Leckie
Keyword(s):  
Damage Mechanics ◽  
Ceramic Matrix Composites ◽  
Continuum Damage Mechanics ◽  
General Criterion ◽  
Matrix Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Damage Models ◽  
Pull Out ◽  
Fracture Features

Fiber pull-out is one of the fracture features of fiber-reinforced ceramic matrix composites. The onset of this mechanism is predicted by using continuum damage mechanics, and corresponds to a localization of deformation. After deriving two damage models from a uniaxial bundle approach, different configurations are analyzed through numerical methods. For one model some very simple criteria can be derived, whereas for the second one none of these criteria can be derived and the general criterion of localization must be used.

Micromechanics Approach for the Overall Elastic Properties of Ceramic Matrix Composites Incorporating Defect Structures

2020 ◽  
Author(s):  
Rajesh S. Kumar
Keyword(s):  
Elastic Properties ◽  
Volume Fraction ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Volume Shrinkage ◽  
Matrix Composites ◽  
Defect Structures ◽  
Linear Elastic ◽  
Elastic Tensor ◽  
The Matrix

Abstract Initial mechanical behavior of Ceramic Matrix Composites (CMCs) is linear until the proportional limit. This initial behavior is characterized by linear elastic properties, which are anisotropic due to the orientation and arrangement of fibers in the matrix. The linear elastic properties are needed during various phases of analysis and design of CMC components. CMCs are typically made with ceramic unidirectional or woven fiber preforms embedded in a ceramic matrix formed via various processing routes. The matrix processing of interest in this work is that formed via Polymer Impregnation and Pyrolysis (PIP). As this process involves pyrolysis process to convert a pre-ceramic polymer into ceramic, considerable volume shrinkage occurs in the material. This volume shrinkage leads to significant defects in the final material in the forms of porosity of various size, shape, and volume fraction. These defect structures can have a significant impact on the elastic and damage response of the material. In this paper, we develop a new micromechanics modeling framework to study the effects of processing-induced defects on linear elastic response of a PIP-derived CMC. A combination of analytical and computational micromechanics approaches is used to derive the overall elastic tensor of the CMC as a function of the underlying constituents and/or defect structures. It is shown that the volume fraction and aspect ratio of porosity at various length-scales plays an important role in accurate prediction of the elastic tensor. Specifically, it is shown that the through-thickness elastic tensor components cannot be predicted accurately using the micromechanics models unless the effects of defects are considered.

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