Reliability Analysis of Ceramic Matrix Composite Laminates

1993 ◽  
Vol 115 (1) ◽  
pp. 117-121 ◽  
Author(s):  
D. J. Thomas ◽  
R. C. Wetherhold
Keyword(s):  
Composite Laminates ◽  
Ceramic Matrix Composite ◽  
Random Variable ◽  
Ceramic Matrix ◽  
Matrix Cracking ◽  
Bundle Theory ◽  
Fiber Direction ◽  
The Matrix ◽  
Failure Models ◽  
Subsequent Failure

At a macroscopic level, a composite lamina may be considered as a homogeneous orthotropic solid whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or noninteractive, allows for the evaluation of the lamina reliability under a given stress state. Using a noninteractive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occurs. The matrix cracking predicted by ACK theory is modeled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results using this modified bundle model are compared with previous models, which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data.

scholarly journals Reliability Analysis of Ceramic Matrix Composite Laminates

1991 ◽  
Author(s):  
David J. Thomas ◽  
Robert C. Wetherhold
Keyword(s):  
Composite Laminates ◽  
Ceramic Matrix Composite ◽  
Random Variable ◽  
Ceramic Matrix ◽  
Matrix Cracking ◽  
Bundle Theory ◽  
Fiber Direction ◽  
The Matrix ◽  
Failure Models ◽  
Subsequent Failure

At a macroscopic level, a composite lamina may be considered as a homogeneous orthotropic solid whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or non-interactive, allows for the evaluation of the lamina reliability under a given stress state. Using a non-interactive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occur. The matrix cracking predicted by ACK theory is modelled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results using this modified bundle model are compared with previous models which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data.

INTERFACIAL BEHAVIOR OF NICALON-FIBER-FEINFORCED GLASS-CERAMIC MATRIX COMPOSITE DUE TO CREEP-CONDITIONING

2002 ◽  
Vol 16 (01n02) ◽  
pp. 85-92 ◽  
Author(s):  
S. WIDJAJA ◽  
T. H. YIP ◽  
A. M. LIMARGA ◽  
S. LI
Keyword(s):  
Matrix Composite ◽  
Glass Ceramic ◽  
Load Transfer ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Matrix Cracking ◽  
Failure Behavior ◽  
Interfacial Behavior ◽  
Conditioning Treatment ◽  
The Matrix

Creep-conditioning had been shown to be effective in inducing a compressive residual stress in the matrix of SiC-fiber-reinforced BMAS glass-ceramic matrix composite. The increase in the compressive stress in the matrix manifested in the increase in the proportional limit of the crept specimens, as compared to that of the as-received. The change of residual stresses in the composite due to creep-load transfer was evaluated through mechanical testing and X-ray diffraction. Microstructural studies on the fracture surfaces and fiber/matrix interface showed that no interfacial reaction or any significant change in the failure behavior of the composite was observed. Interfacial sliding stress at the interface, obtained from a fiber push-out test, revealed that essentially there was no change in the normal clamping stress. The results confirmed that creep-conditioning treatment, intended to increase the matrix cracking stress, could be successfully applied to composite materials without sacrificing the "composite-like" fracture behaviors.

A Three-Phase Shear-Lag Model for Longitudinal Cracking of a Ceramic Matrix Composite Ply With Thick Fiber Coatings

2015 ◽  
Vol 83 (1) ◽  
Author(s):  
Lucas R. Hansen ◽  
Anthony M. Waas
Keyword(s):  
Ceramic Matrix Composite ◽  
Stress Transfer ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Cracking ◽  
Material System ◽  
Shear Lag ◽  
Thick Fiber ◽  
The Matrix ◽  
Lag Model

During progressive cracking of cross-ply ceramic matrix composites (CMCs), load is transferred from the fiber to the matrix in the longitudinal (0 deg) ply via shear through a compliant interphase layer, also referred to as the coating. In the material system of interest, this coating has significant thickness relative to the fiber diameter. The damage process in the cross-ply CMC is observed to be as follows: (1) elastic deformation, (2) cracking of the transverse plies, (3) matrix cracking within the longitudinal plies, (4) failure of longitudinal fibers, and (5) pullout of the cracked fibers from the matrix. In this paper, the focus is on the longitudinal (0 deg) ply. Existing shear-lag models do not fully represent either the stress transfer through the coating or the true accumulations of shear and normal stresses in the matrix. In the current study, a model is developed that takes into account both of these factors to provide a more accurate, analytical representation of the stress distribution and progressive damage accumulation in a longitudinal CMC ply.

A Review of Failure Models for Ceramic Matrix Composite Laminates Under Monotonic Loads

1990 ◽  
Vol 112 (4) ◽  
pp. 492-501 ◽  
Author(s):  
D. E. Tripp ◽  
J. H. Hemann ◽  
J. P. Gyekenyesi
Keyword(s):  
Matrix Composite ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Failure Models ◽  
Monotonic Loads ◽  
Semi Empirical

Ceramic matrix composites offer significant potential for improving the performance of turbine engines. In order to achieve their potential, however, improvements in design methodology are needed. In the past most components using structural ceramic matrix composites were designed by “trial and error” since the emphasis on feasibility demonstration minimized the development of mathematical models. To understand the key parameters controlling response and the mechanics of failure, the development of structural failure models is required. A review of short-term failure models with potential for ceramic matrix composite laminates under monotonic loads is presented. Phenomenological, semi-empirical, shear-lag, fracture mechanics, damage mechanics, and statistical models for the fast fracture analysis of continuous fiber unidirectional ceramic matrix composites under monotonic loads are surveyed.

Multiscale Modelling of the Influence of Damage on the Thermal Properties of Ceramic Matrix Composites

2010 ◽  
Vol 73 ◽  
pp. 65-71 ◽  
Author(s):  
Jalal El Yagoubi ◽  
Jacques Lamon ◽  
Jean Christophe Batsale
Keyword(s):  
Thermal Loading ◽  
Interfacial Crack ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Cracking ◽  
Fiber Direction ◽  
Multiple Cracks ◽  
Matrix Composites ◽  
Structural Applications ◽  
The Matrix

Ceramic matrix composites (CMC) are very attractive materials for structural applications at high temperatures. Not only must CMC be damage tolerant, but they must also allow thermal management. For this purpose heat transfers must be controlled even in the presence of damage. Damage consists in multiple cracks that form in the matrix and ultimately in the fibers, when the stresses exceed the proportional limit. Therefore the thermal conductivity dependence on applied load is a factor of primary importance for the design of CMC components. This original approach combines a model of matrix cracking with a model of heat transfer through an elementary cracked volume element containing matrix crack and an interfacial crack. It was applied to 1D composites subject to tensile ant thermal loading parallel to fiber direction in a previous paper. The present paper compares predictions to experimental results.

A Review of Failure Models for Ceramic Matrix Composite Laminates Under Monotonic Loads

1989 ◽  
Author(s):  
David E. Tripp ◽  
John H. Hemann ◽  
John P. Gyekenyesi
Keyword(s):  
Matrix Composite ◽  
Composite Laminates ◽  
Damage Mechanics ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Failure Models ◽  
Monotonic Loads ◽  
Semi Empirical

Ceramic matrix composites offer significant potential for improving the performance of turbine engines. In order to achieve their potential, however, improvements in design methodology are needed. In the past most components using structural ceramic matrix composites were designed by “trial and error” since the emphasis on feasibility demonstration minimized the development of mathematical models. To understand the key parameters controlling response and the mechanics of failure, the development of structural failure models is required. A review of short term failure models with potential for ceramic matrix composite laminates under monotonic loads is presented. Phenomenological, semi-empirical, shear-lag, fracture mechanics, damage mechanics, and statistical models for the fast fracture analysis of continuous fiber unidirectional ceramic matrix composites under monotonic loads are surveyed.

Thermal Diffusivity Imaging of Ceramic Composites

1993 ◽  
Author(s):  
K. Elliott Cramer ◽  
William P. Winfree ◽  
Edward R. Generazio ◽  
Ramakrishna Bhatt ◽  
Dennis S. Fox ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Diffusivity ◽  
Silicon Nitride ◽  
Matrix Material ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Ceramic Composites ◽  
Fiber Direction ◽  
Large Area

Strong, tough, high temperature ceramic matrix composites are currently being developed for application in advanced heat engines. One of the most promising of these new materials is a SiC fiber-reinforced silicon nitride ceramic matrix composite (SiCf/Si3N4). The interfacial shear strength in such composites is dependant on the integrity of the fiber’s carbon coating at the fiber-matrix interface. The integrity of the carbon rich interface can be significantly reduced if the carbon is oxidized. Since the thermal diffusivity of the fiber is greater than that of the matrix material, the removal of carbon increases the contact resistance at the interface reducing the thermal diffusivity of the composite. Therefore thermal diffusivity images can be used to characterize the progression of carbon depletion and degradation of the composite. A new thermal imaging technique has been developed to provide rapid large area measurements of the thermal diffusivity perpendicular to the fiber direction in these composites. Results of diffusivity measurements will be presented for a series of SiCf/Si3N4 (reaction bonded silicon nitride) composite samples heat-treated under various conditions. Additionally, the ability of this technique to characterize damage in both ceramic and other high temperature composites will be shown.

A Pre-Stitching Method to Manufacture Z-Pins Reinforced Woven Ceramic Matrix Composite Laminates

2013 ◽  
Vol 721 ◽  
pp. 117-120
Author(s):  
Wei Liu ◽  
Gui Qiong Jiao ◽  
Jing Guo ◽  
Hao Tian Jiang
Keyword(s):  
Carbon Fibers ◽  
Composite Laminates ◽  
Impact Resistance ◽  
Ceramic Matrix Composite ◽  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Chemical Vapor Infiltration ◽  
Matrix Composites ◽  
Delamination Resistance

Z-pins reinforced 2D ceramic matrix composites (CMCs), integratedly designed new materials, are developed to enhance 2D CMCs through-thickness in the form of Z-pins and to ensure significant increase in interlaminar fracture toughness, delamination resistance and impact resistance, and Z-pins reinforced 2D CMCs have much application. A manual pre-stitching method is developed to make holes in the graphite fixture to control Z-pins row spacings and to introduce yarns of 3000 T300 carbon fibers bundle into a preform. Z-pins reinforced woven CMCs for research were manufactured successfully by repeatedly using chemical vapor infiltration (CVI) to infiltrate SiC matrix into woven preform and carbon fiber sutures. It is shown that this method of manufactured Z-pins reinforced woven CMC is feasible.

scholarly journals Multiple Matrix Cracking of Fiber-Reinforced Ceramic-Matrix Composites during Operation

2020 ◽  
Author(s):  
Chengzheng Zhu
Keyword(s):  
Ceramic Matrix Composite ◽  
Weight Ratio ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Aircraft Engine ◽  
Matrix Cracking ◽  
Civil Aviation ◽  
Inlet Temperature ◽  
Flight Safety ◽  
Fiber Reinforced

In the field of civil aviation, the most important factor is safety quality. Improving aircraft performance can increase flight safety factor in some degree. To improve the thrust-to-weight ratio of aircraft engines and reduce fuel consumption, the fundamental measure is to increase the turbine inlet temperature of engines, while hot-section components is directly related to the maximum allowable operating temperature. Ceramic-matrix composite (CMC) material is one of the important candidate materials for aeroengine. To improve CMCs in aircraft engine application, it is necessary to investigate the failure mechanism of CMCs and also failure models. However, during operation, matrix multiple cracking occurs with fiber debonding and fracture, which affects the flight safety and failure risk. In this chapter, the multiple matrix cracking of fiber-reinforced CMCs is investigated using energy balance approach.

Sign in / Sign up

Export Citation Format

Share Document