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.

scholarly journals Stress Transfer from Axially Loaded Fiber to Matrix in a Microcomposite

1994 ◽  
Vol 365 ◽  
Author(s):  
Chun-Hway Hsueh
Keyword(s):  
Analytical Solutions ◽  
Volume Fraction ◽  
Axial Stress ◽  
Stress Transfer ◽  
Radial Dependence ◽  
Shear Lag ◽  
Shear Lag Model ◽  
The Matrix ◽  
Lag Model ◽  
Loaded Fiber

ABSTRACTThe shear lag model has been used extensively to analyze the stress transfer in a singe fiberreinforced composite (i.e., a microcomposite). To achieve analytical solutions, various simplifications have been adopted in the stress analysis. Questions regarding the adequacy of those simplifications are discussed in the present study for the following two cases: bonded interfaces and frictional interfaces. Specifically, simplifications regarding (1) Poisson's effect, and (2) the radial dependences of axial stresses in the fiber and the matrix are addressed. For bonded interfaces, the former can be ignored, and the latter can generally be ignored. However, when the volume fraction of the fiber is high, the radial dependence of the axial stress in the fiber should be considered. For frictional interfaces, the latter can be ignored, but the former should be considered; however, it can be considered in an average sense to simplify the analysis. Comparisons among results obtained from analyses with various simplifications are made.

Investigation of Damage in Unidirectional Ceramic Matrix Composites Using a Cohesive-Shear-Lag Model

2001 ◽  
Author(s):  
B. Yang ◽  
S. Mall
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Debonding ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Shear Lag ◽  
Stress Strain ◽  
Unidirectional Fiber ◽  
Shear Lag Model ◽  
Lag Model

Abstract The present study develops a cohesive-shear-lag model to analyze the cycling stress-strain behavior of unidirectional fiber-reinforced ceramic matrix composites. The model, as a modification to a classical shear-lag model, takes into account matrix cracking, partial interfacial debonding, and partial breakage of fibers. The statistical nature of partial breakage of fibers is modeled by using a cohesive force law. The validity of the model is demonstrated by investigating stress-strain hysteresis loops of a unidirectional fiber-reinforced ceramic-glass matrix composite, SiC/1723. This example demonstrates the capability of the proposed model to characterize damage and deformation mechanisms of ceramic matrix composites under tension-tension cycling loading. The dominant progressive damage mechanism with cycling in this case is shown to be accumulation of fibers breakage, accompanied by increase in interfacial debonding and smoothening of frictional debonded interface.

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 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.

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.

High Temperature Solid Particle Erosion in a Melt-Infiltrated SiC/SiC Ceramic Matrix Composite

2021 ◽  
Author(s):  
Michael J. Presby
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Gas Turbines ◽  
Material Removal ◽  
Gas Flow ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Solid Particles ◽  
Material System

Abstract Ceramic matrix composites (CMCs) are an enabling propulsion material system that offer weight benefits over current Ni-based superalloys, and have higher temperature capabilities that can reduce cooling requirements. Incorporating CMCs into the hot section of gas-turbine engines therefore leads to an increase in engine efficiency. While significant advancements have been made, challenges still remain for current and next-generation gas-turbines; particularly when operating in dust-laden or erosive environments. Solid particles entrained in the gas flow can impact engine hardware resulting in localized damage and material removal due to repeated, cumulative impacts. In this study, the erosion behavior of a melt-infiltrated (MI) silicon carbide fiber-reinforced silicon carbide (SiC/SiC) CMC is investigated at high temperature (1,200 °C) in a simulated combustion environment using 150 μm alumina particles as erodent. Particle impact velocities ranged from 100 to 200 m/s and the angle of impingement varied from 30° to 90°. Erosion testing was also performed on α-SiC to elucidate similarities and differences in the erosion response of the composite compared to that of a monolithic ceramic. Scanning electron microscopy (SEM) was used to study the post-erosion damage morphology and the governing mechanisms of material removal.

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.

scholarly journals Development of a System for Additive Manufacturing of Ceramic Matrix Composite Structures Using Laser Technology

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3248
Author(s):  
Stefan Polenz ◽  
Willy Kunz ◽  
Benjamin Braun ◽  
Andrea Franke ◽  
Elena López ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Composite Structures ◽  
Matrix Material ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Test System ◽  
Ceramic Fiber ◽  
Integrating Sphere ◽  
Material System ◽  
The Matrix

Ceramic matrix composites (CMCs) are refractory ceramic materials with damage-tolerant behavior. Coming from the space industry, this class of materials is increasingly being used in other applications, such as automotive construction for high-performance brake discs, furnace technology, heat coatings for pipe systems and landing flaps on reusable rocket sections. In order to produce CMC faster and more cost-efficiently for the increasing demand, a new additive manufacturing process is being tested, which in the future should also be able to realize material joints and higher component wall thicknesses than conventional processes. The main features of the process are as follows. A ceramic fiber bundle is de-sized and infiltrated with ceramic suspension. The bundle infiltrated with matrix material is dried and then applied to a body form. During application, the matrix material is melted by laser radiation without damaging the fiber material. For the initial validation of the material system, samples are pressed and analyzed for their absorption properties using integrating sphere measurement. With the results, a suitable processing laser is selected, and initial melting tests of the matrix system are carried out. After the first validation of the process, a test system is set up, and the first test specimens are produced to determine the material parameters.

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.

scholarly journals Densification of Ceramic Matrix Composite Preforms by Si2N2O Formed by Reaction of Si with SiO2 under High Nitrogen Pressure. Part 1: Materials Synthesis

2021 ◽  
Vol 5 (7) ◽  
pp. 178
Author(s):  
Brice Taillet ◽  
René Pailler ◽  
Francis Teyssandier
Keyword(s):  
Heating Rate ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Nitrogen Pressure ◽  
Major Influence ◽  
High Nitrogen ◽  
Joule Effect ◽  
The Matrix ◽  
High Nitrogen Pressure

Ceramic matrix composites (CMCs) have been designed and developed for extreme operating environments. The aim of the present study is to look for a rapid densification process providing a high level of material performance. The fibrous preform was made of Hi-Nicalon S fibers woven in a 3D interlock weave. The matrix was composed of Si2N2O prepared inside the CMCs by reacting a mixture of Si and SiO2 under high nitrogen pressure (1 to 3 MPa). Silica was either impregnated by slurry or obtained by oxidation of silicon grains inside the preform. The synthesis reaction was initiated by heating the impregnated preform by means of a carbon resistor submitted to Joule effect. Composition, homogeneity and porosity of the formed matrix were studied and interpreted as a function of the experimental parameters (nitrogen pressure, heating rate of the preform) as well as the recorded thermal history of the process. The present results show that the matrix formation is almost completed in less than one minute. Melting of silicon has a major influence on the process. Competition was observed between the formation of Si3N4 and Si2N2O, which could be mainly controlled by the heating rate of the preform and the nitrogen partial pressure.

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