The Matrix Cracking Stress and Residual Thermal Stress of 2D SiC/SiC Composite Fabricated by PIP Process

2018 ◽  
Vol 281 ◽  
pp. 375-381
Author(s):  
Hai Peng Qiu ◽  
Shan Hua Liu ◽  
Ling Wang ◽  
Bing Yu Zhang ◽  
Ming Wei Chen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Regression Line ◽  
Strain Curve ◽  
Thermal Residual Stress ◽  
Matrix Cracking ◽  
Stress Strain Curve ◽  
Sic Ceramic ◽  
The Matrix ◽  
Sic Composites ◽  
Cracking Stress

A two dimensional silicon carbide fiber reinforced SiC matrix (2D SiC/SiC) composite fabricated by precursor infiltration pyrolysis (PIP) process used a liquid SiC ceramic precursor was obtained. Two key properties including matrix cracking stress and thermal residual stress were investigated for this PIP 2D SiC/SiC composites. Three methods were applied to determine the matrix cracking stress in order to obtained a trusted value, and the value of matrix cracking stress for SiC/SiC composite was 75±4 MPa. The thermal residual stress of the composites was calculated by linear regression line according to the loading-unloading-reloading stress-strain curve of the 2D SiC/SiC composite, and the result showed that the value of thermal residual stress of SiC matrix in composite was 20MPa, which means the PIP SiC matrix in the 2D SiC/SiC composite was under the compressive stress when the composite cooling down from the fabrication temperature to the room temperature.

scholarly journals A machine learning framework for damage mechanism identification from acoustic emissions in unidirectional SiC/SiC composites

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
C. Muir ◽  
B. Swaminathan ◽  
K. Fields ◽  
A. S. Almansour ◽  
K. Sevener ◽  
...  
Keyword(s):  
Domain Knowledge ◽  
Acoustic Emissions ◽  
Damage Mechanism ◽  
Matrix Cracking ◽  
Fiber Failure ◽  
Learning Framework ◽  
Sic Ceramic ◽  
The Matrix ◽  
Fiber Breaks ◽  
Sic Composites

AbstractIn this work, we demonstrate that damage mechanism identification from acoustic emission (AE) signals generated in minicomposites with elastically similar constituents is possible. AE waveforms were generated by SiC/SiC ceramic matrix minicomposites (CMCs) loaded under uniaxial tension and recorded by four sensors (two models with each model placed at two ends). Signals were encoded with a modified partial power scheme and subsequently partitioned through spectral clustering. Matrix cracking and fiber failure were identified based on the frequency information contained in the AE event they produced, despite the similar constituent elastic properties of the matrix and fiber. Importantly, the resultant identification of AE events closely followed CMC damage chronology, wherein early matrix cracking is later followed by fiber breaks, even though the approach is fully domain-knowledge agnostic. Additionally, the partitions were highly precise across both the model and location of the sensors, and the partitioning was repeatable. The presented approach is promising for CMCs and other composite systems with elastically similar constituents.

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.

Modeling the Matrix of Articular Cartilage Using a Continuous Fiber Angular Distribution Predicts Many Observed Phenomena

2009 ◽  
Author(s):  
Gerard A. Ateshian ◽  
Vikram Rajan ◽  
Nadeen O. Chahine ◽  
Clare Canal Guterl ◽  
Clark T. Hung
Keyword(s):  
Angular Distribution ◽  
Mechanical Response ◽  
Strain Curve ◽  
Collagen Matrix ◽  
Compressive Properties ◽  
Continuous Fiber ◽  
Stress Strain Curve ◽  
Theoretical Frameworks ◽  
The Matrix ◽  
Discrete Fiber

A number of theoretical frameworks embodying the disparity between tensile and compressive properties of cartilage have been proposed, accounting for the collagen fibers implicitly [1,2] or explicitly [3–5]. These models generally propose discrete fiber families to describe the collagen matrix. They are able to capture the most salient features of the cartilage mechanical response, namely, the tension-compression nonlinearity of the stress-strain curve [6].

Damage Evolution of the Interphase on C/SiC Composites with CZM Method

2012 ◽  
Vol 166-169 ◽  
pp. 2847-2850
Author(s):  
Yan Jun Chang ◽  
Zhuo Li ◽  
Ke Shi Zhang
Keyword(s):  
Residual Stress ◽  
Damage Evolution ◽  
Fem Analysis ◽  
Matrix Crack ◽  
Thermal Residual Stress ◽  
Analysis Model ◽  
Initial Matrix ◽  
Thermal Residual Stresses ◽  
Initiation And Propagation ◽  
Sic Composites

Considering thermal residual stress and initial matrix crack, the cylinder FEM analysis model for C/SiC tow was established. The cohesive element and damage criterions were introduced to simulation the initiation and propagation of interphase crack processes of C/SiC composites. The thermal residual stresses release with the initial matrix crack and the cracking on interphase. The interphase crack length was dominated by the performance of interphase. Analysis demonstrated that the CZM model can simulate well the thermal residual stress and the delamination of the interphase.

Matrix Cracking In Brittle-Matrix Composites with Tailored Interfaces

1994 ◽  
Vol 365 ◽  
Author(s):  
Sawai Danchaivijit ◽  
L-Y. Chao ◽  
D. K. Shetfty
Keyword(s):  
Steady State ◽  
Crack Length ◽  
Uniaxial Tension ◽  
Sliding Friction ◽  
Crack Opening ◽  
State Theory ◽  
Matrix Cracking ◽  
Opening Displacement ◽  
The Matrix ◽  
Cracking Stress

ABSTRACTMatrix cracking from controlled through cracks with bridging filaments was studied in a model unidirectional composite of SiC filaments in an epoxy-bonded alumina matrix. An unbonded, frictional interface was produced by moderating the curing shrinkage of the epoxy with the alumina filler and coating the filaments with a releasing agent. Uniaxial tension test specimens (2.5 × 25 × 125 mm) with filament-bridged through cracks were fabricated by a novel two-step casting technique involving casting, precracking and joining of cracked and uncracked sections. Distinct matrix-cracking stresses, corresponding to the extension of the filamentbridged cracks, were measured in uniaxial tension tests using a high-sensitivity extensometer. The crack-length dependence of the matrix-cracking stress was found to be in good agreement with the prediction of a fracture-mechanics analysis that employed a new crack-closure force - crack-opening displacement relation in the calculation of the stress intensity for fiber-bridged cracks. The prediction was based on independent experimental measurements of the matrix fracture toughness (Kcm), the interfacial sliding friction stress (τ) and the residual stress in the matrix (σmI). The matrix-cracking stress for crack lengths (2a) greater than 3 mm was independent of the crack length and agreed with the prediction of the steady-state theory of Budiansky, Hutchinson and Evans[2]. Tests on specimens without the deliberately introduced cracks indicated a matrix-cracking stress significantly higher than the steady-state stress.

scholarly journals Residual stress variation in SiCf/SiC composite during heat treatment and its effects on mechanical behavior

2020 ◽  
Author(s):  
Xiaowu Chen ◽  
Guofeng Cheng ◽  
Junmin Zhang ◽  
Feiyu Guo ◽  
Haijun Zhou ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Reduction ◽  
Tensile Strain ◽  
Room Temperature ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
Stress Variation ◽  
Sic Fiber ◽  
The Matrix ◽  
Sic Composites

Abstract Residual stress originated from thermal expansion mismatch determines the mechanical properties of ceramic matrix composites (CMCs). Here, continuous SiC fiber reinforced SiC matrix (SiCf/SiC) composites were fabricated by nano-infiltration and transient eutectic-phase (NITE) method, and variation of residual stress in the constituent phases was investigated using high-temperature Raman spectrometer. With temperature increasing from room temperature to 1400°C, residual stresses of the matrix and the fiber decrease from 1.29 GPa to 0.62 GPa and from 0.84 GPa to 0.55 GPa in compression respectively, while that of the interphase decreases from 0.16 GPa to 0.10 GPa in tension. The variation of residual stress shows little effect in the tensile strength of the composites, while causes a slight decrease in the tensile strain. Suppression of fiber/matrix debonding and fiber pulling-out caused by the residual stress reduction in the interphase is responsible for the decreasing tensile strain. This work can open up new alternatives for residual stress analysis in CMCs.

Tensile Creep Behavior of Melt-Infiltrated SiC-SiC Composites for Gas Turbine Engine Applications

2007 ◽  
Author(s):  
Vijay V. Pujar ◽  
Gregory N. Morscher
Keyword(s):  
Ceramic Matrix Composites ◽  
Matrix Cracking ◽  
Tensile Creep ◽  
Matrix Composites ◽  
Creep Tests ◽  
Turbine Engine ◽  
Sic Ceramic ◽  
Melt Infiltration ◽  
Sic Composites ◽  
Engine Components

SiC-SiC ceramic matrix composites (CMCs) manufactured by the melt-infiltration (MI) process are considered leading candidates for hot-section turbine engine components. MI composites consisting of different commercially available SiC fibers were fabricated and their room temperature and elevated temperature performance was evaluated. In this paper, results on the performance of composites under tensile creep conditions and the properties of these materials retained after creep are discussed. Specimens were subjected to 100-h creep tests at different stress levels. For samples that did not rupture during creep, retained tensile properties were measured after creep and compared to those on the as-produced samples. Interestingly, the after-creep specimens show higher 0.005% offset stresses (or matrix cracking strengths) relative to those in the as-produced materials, which is attributed to redistribution of stresses among the constituents during the tensile creep test. That is, the results show that the offset stresses in these materials can actually improve with use under tensile creep conditions, which is a desirable attribute for components of these materials for turbine engines.

Effects of Curing-Induced Residual Stress on Composite Strength

2020 ◽  
Author(s):  
Haotian Sun ◽  
Dianyun Zhang
Keyword(s):  
Residual Stress ◽  
Damage Model ◽  
Matrix Cracking ◽  
Bending Test ◽  
Composite Strength ◽  
Plain Weave ◽  
The Matrix ◽  
Smeared Crack Approach ◽  
Fiber Matrix ◽  
Stress Buildup

Abstract An integrated processing-damage model was developed to predict the inter-lamina strength of a plain weave composite flange manufactured using the Resin Transfer Molding (RTM) technique. The plain weave composite flange was subjected to four-point bending test to characterize its inter-lamina strength. A Representative Volume Element (RVE) at the fiber–matrix level was established to study the effect of curing-induced residual stress on the resulting composite strength. In order to calculate the residual stress, the curing cycle of the experiment was imposed on the RVE. After fully cured, the RVE was virtually loaded and the cohesive element and Smeared Crack Approach (SCA) were employed to capture the fiber-matrix debonding and matrix cracking responses, respectively. Due to the nature of stress history dependency, the SCA was formulated in the incremental form to reflect the stress buildup. The result shows that both fiber-matrix debonding and matrix cracking can be captured during the virtual loading. However, the load drop in the simulation mainly depends the matrix cracking. As the stress buildup in the matrix is dramatic, it demonstrates that the residual stress has large impact on the composite inter-lamina strength. The numerical methods in this paper can be used as an efficient tool in optimizing the curing process of composite material.

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