Damage Mechanics of Two-Dimensional Woven SiC/SiC Composites

1994 ◽  
Vol 116 (3) ◽  
pp. 403-407 ◽  
Author(s):  
Hui-Zu Shan ◽  
Philippe Pluvinage ◽  
Azar Parvizi-Majidi ◽  
Tsu-Wei Chou
Keyword(s):  
Experimental Data ◽  
Damage Mechanics ◽  
Damage Model ◽  
Ceramic Matrix Composites ◽  
Elastic Behavior ◽  
Two Dimensional ◽  
Compression Tests ◽  
Damage Development ◽  
Tension And Compression ◽  
Sic Composites

The paper reports an analysis and modeling of the damage behavior of two-dimensional woven SiC/SiC composites. The damage mechanics analysis originally developed by Ladeveze and coworkers for polymeric and C/C composites are adopted and extended for ceramic matrix composites. The experimental findings of the coauthors reported in a companion paper provides the data for analytical modeling. The damage model assumes quasi-isotropic elastic behavior of the undamaged SiC/ SiC composites as well as orthotropic damage development (e.g., matrix microcracking, interfacial debonding, and fiber fracture). The model utilize two damage variables which are determined from experimental data; and the constitutive relation takes into account the difference in damage development between tension and compression in the principal material directions. The validity of the theory is demonstrated by the prediction of damage evolution of a SiC/SiC specimen under four-point bend test based upon the experimental data of tension and compression tests. A finite element method coupled with damage is adopted for the flexural analysis. The predictions agree quite well with experimental results.

Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

2021 ◽  
pp. 146442072110134
Author(s):  
A Nayebi ◽  
H Rokhgireh ◽  
M Araghi ◽  
M Mohammadi
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Continuum Damage ◽  
Compression Tests ◽  
Compression Properties ◽  
Mechanics Model ◽  
Stress Components ◽  
Tension And Compression ◽  
Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model

2012 ◽  
Vol 498 ◽  
pp. 42-54 ◽  
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Numerical Model ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Element Analysis ◽  
Progressive Failure Analysis

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.

Accounting for frictional contact in an anisotropic damage model based on compliance tensorial variables, illustration on ceramic matrix composites

2018 ◽  
Vol 28 (8) ◽  
pp. 1150-1169 ◽  
Author(s):  
Emmanuel Baranger
Keyword(s):  
Damage Mechanics ◽  
A Priori ◽  
Damage Model ◽  
Ceramic Matrix Composites ◽  
Inelastic Strain ◽  
Ceramic Matrix ◽  
Thermomechanical Properties ◽  
Matrix Composites ◽  
Crack Network ◽  
Evolution Laws

Ceramic matrix composites have good thermomechanical properties at high or very high temperatures. The modeling of the crack networks associated to the degradation of such composites using damage mechanics is not straightforward. The main reason is the presence of a crack network mainly oriented by the loading direction, which is a priori unknown. To model this, compliance tensorial damage variables are used in a thermodynamic potential able to account for crack closure effects (unilateral contact). The damage kinematic is initially completely free and imposed by the evolution laws. The key point of the present paper is to account for friction in such cracks that can result in an apparent activation/deactivation of the shear damage. The initial model is enriched with an inelastic strain and a friction law. The plasticity criterion is expressed only using tensorial variables. The model is identified and illustrated on multiaxial data obtained at ONERA on tubes loaded in tension and torsion.

Damage Development in SiCf/SiC Composites Through Mechanical Loading

2017 ◽  
Author(s):  
Martin R. Bache ◽  
J. Paul Jones ◽  
Zak Quiney ◽  
Louise Gale
Keyword(s):  
Acoustic Emission ◽  
Mechanical Loading ◽  
Ceramic Matrix Composites ◽  
Potential Drop ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Damage Development ◽  
Macro Scale ◽  
Sic Composites ◽  
The Individual

Sophisticated mechanical characterisation is vital in support of a fundamental understanding of deformation in ceramic matrix composites. On the component scale, “damage tolerant” design and lifing philosophies depend upon laboratory assessments of macro-scale specimens, incorporating typical fibre architectures and matrix under representative stress-strain states. Standard SiCf/SiC processing techniques inherently introduce porosity between the individual reinforcing fibres and between woven fibre bundles. Subsequent mechanical loading (static or cyclic) may initiate cracking from these stress concentrations in addition to fibre/matrix decohesion and delamination. The localised coalescence of such damage ultimately leads to rapid failure. Proven techniques for the monitoring of damage in structural metallics, i.e. optical microscopy, potential drop systems, acoustic emission (AE) and digital image correlation (DIC), have been adapted for the characterisation of CMC’s tested at room temperature. As processed SiCf/SiC panels were subjected to detailed X-ray computed tomography (XCT) inspection prior to specimen extraction and subsequent static and cyclic mechanical testing to verify their condition. DIC strain measurements, acoustic emission and resistance monitoring were performed and correlated to monitor the onset of damage during loading, followed by intermittent XCT inspections throughout the course of selected tests.

A Simple Plastic-Damage Model for the Cement-Soil Admixture

2007 ◽  
Vol 353-358 ◽  
pp. 1145-1148 ◽  
Author(s):  
X.J. Yu ◽  
Zhen Fang ◽  
Shan Yong Wang ◽  
Yun Yan ◽  
Jian Hua Yin
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Critical Index ◽  
Fortran Program ◽  
Compression Tests ◽  
Material Degradation ◽  
Softening Behaviour ◽  
Plastic Damage ◽  
Basic Equations ◽  
Cement Soil

An Elastic Plastic-Damage (EPD) model is developed to model the softening behaviour of the cement-soil admixture based on continuous damage mechanics. The softening behaviour is considered to be characteristic outcome of the material degradation due to damage in material. Material degradation is modelled by reducing progressively the stiffness and yield stress of the material when the damage variable has attained a critical index. The basic equations of the model are derived and presented. A Fortran program for this model has been developed and implemented into a finite element code ABAQUS. In order to evaluate the applicability of this model, several unconfined compression tests are simulated using ABAQUS with this model. The computed results are compared with measured data and good agreement is achieved.

Analysis of Concrete Pressure Vessels in the Framework of Continuum Damage Mechanics

2011 ◽  
Vol 21 (6) ◽  
pp. 843-870 ◽  
Author(s):  
M. Ganjiani ◽  
R. Naghdabadi ◽  
M. Asghari
Keyword(s):  
Potential Energy ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Elastic Behavior ◽  
Gibbs Potential ◽  
Continuum Damage ◽  
Shear Damage ◽  
Tension And Compression ◽  
Walled Cylinder ◽  
Tensile Damage

In this article, a constitutive model in the framework of continuum damage mechanics is proposed to simulate the elastic behavior of concrete in tension and compression states. We assume two parts for Gibbs potential energy function: elastic and damage parts. In order to obtain the elastic-damage constitutive relation with the internal variables, two damage thermodynamic release rates in tension and compression derived from the elastic part of Gibbs potential energy are introduced. Also, two anisotropic damage tensors (tension and compression) are defined which characterize the tensile and compressive behaviors of concrete. Furthermore, two different linear hardening rules for tension and compression states are adopted for characterizing the damage evolution. The spectral decomposition technique is used to resolve the stress tensor into tensile and compressive components. The accuracy and performance of the proposed model are validated by comparing the predicted results with different experimental data, such as monotonic uniaxial tension and compression tests, and monotonic biaxial compression test. As an application, an analytic closed-form solution for a concrete thick-walled cylinder is obtained. It is shown that two damages: tensile damage [Formula: see text] and shear damage [Formula: see text] propagate in the cylinder. These two damages introduce anisotropy in the elastic behavior of the concrete structure. The influence of these two damages is investigated on the stress field in the cylinder. It is found that effect of shear damage [Formula: see text] on radial and tangential stresses as well as the effect of tensile damage [Formula: see text] on radial stress are negligible, while the effect of tensile damage [Formula: see text] on the tangential stress in a concrete thick-walled cylinder is significant.

Damage Mechanics of Dual Systems

2015 ◽  
pp. 412-444
Keyword(s):  
Digital Image Correlation ◽  
Aspect Ratio ◽  
Damage Mechanics ◽  
Damage Model ◽  
Image Correlation ◽  
Elastic Behavior ◽  
Special Technique ◽  
Dual Systems ◽  
Plastic Deformations ◽  
Griffith Criterion

This chapter begins with the presentation of some experimental results on RC specimens using a special technique called “digital image correlation.” Then, it describes a damage model for RC walls. Next, the model is generalized to include elements with any aspect ratio; finally, the analysis of dual system is described and some numerical simulations are presented. Notice that Section 3.4 described the elastic behavior of dual systems; in section 7.3 that model was extended to include plastic deformations. The goal of this chapter is to generalize that model, including cracking propagation described by the Griffith criterion or its modified version.

Constituent and Ply Level Understanding of Electrical Resistance in Si-Containing SiC/SiC Composites

2021 ◽  
Author(s):  
Joseph El Rassi ◽  
Gregory N. Morscher
Keyword(s):  
Electrical Resistance ◽  
Ceramic Matrix Composites ◽  
Potential Drop ◽  
Matrix Composites ◽  
Damage Development ◽  
Laminate Composites ◽  
Monitoring Technique ◽  
Measured Resistance ◽  
Sic Composites ◽  
Current Potential

Abstract Electrical resistance, also known as direct current potential drop (DCPD), has been demonstrated as an enabling means to monitor damage evolution in SiC-based ceramic matrix composites. For laminate composites, it has become apparent that the location and orientation of SiC fibers, free Si and in some cases insertion of C rods can greatly affect the measured resistance. In addition, the nature of crack growth through the different plies which consist of different constituents will have different effects on the change in resistance. Therefore, both experimental and modeling approaches as to the resistance and change in resistance for different laminate architectures based on the nature of constituent content and orientation are needed to utilize and optimize electrical resistance as a health-monitoring technique. In this work, unidirectional and cross-ply laminate composites have been analyzed using a ply-based electrical model. Based on a ply-level circuit model, the change in resistance was modeled for damage development. It is believed that this can serve as a basis for tailoring the architecture/constituent content to create a “smarter” composite.

scholarly journals Prediction of Failure in Ceramic Matrix Composites Using Damage-Based Failure Criterion

2020 ◽  
Vol 4 (4) ◽  
pp. 183
Author(s):  
Neraj Jain ◽  
Dietmar Koch
Keyword(s):  
Failure Criterion ◽  
Damage Mechanics ◽  
Shear Test ◽  
Damage Model ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Filament Winding ◽  
Material Behavior ◽  
Matrix Composites ◽  
Inelastic Behavior

This paper presents a damage-based failure criterion and its implementation in order to predict failure in ceramic matrix composites (CMC) manufactured via filament winding. The material behavior of CMCs is anisotropic and strongly depends on the angle between fiber orientation and loading direction. The inelastic behavior of laminates with different fiber orientations under tension and shear is modeled with the help of continuum damage mechanics. The parameters required for the damage model are obtained from a standard tensile and shear test. An isotropic damage law determines the evolution of damage in thermodynamic space and considers the interaction of damage parameters in different principal material directions. A quadratic damage-based failure criterion inspired by the Tsai-Wu failure criterion is proposed. Failure stress and strain can be predicted with higher accuracy compared to the Tsai-Wu failure criterion in stress- or strain-space. The use of the proposed damage limits allows designing a CMC component based on the microstructural phenomenon of stiffness loss. With the help of results obtained from modeling and experiments, fracture mechanics during the Iosipescu-shear test of CMCs and its capability to determine the shear strength of the material is discussed.

A thermodynamics-based damage model for the non-linear mechanical behavior of SiC/SiC ceramic matrix composites in irradiation and thermal environments

2020 ◽  
Vol 29 (10) ◽  
pp. 1569-1599
Author(s):  
Mohammad Alabdullah ◽  
Nasr M Ghoniem
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Behavior ◽  
Damage Mechanics ◽  
Damage Model ◽  
Ceramic Matrix Composites ◽  
Irradiation Damage ◽  
Continuum Damage ◽  
Wide Spread ◽  
Thermodynamic Framework ◽  
Non Linear

A damage model is developed and validated with experimental data for the non-linear mechanical behavior of SiC/SiC composite materials in nuclear applications. Cyclic thermal and mechanical loading associated with neutron irradiation effects of these composites leads to wide-spread and progressive micro-cracking that leads to loss of thermal conductivity and further enhancement of thermo-mechanical damage. A physics-based model of wide-spread micro-cracking is developed within the thermodynamic framework of continuum damage mechanics. Evolution equations for damage parameters that describe the growth of continuum damage are developed, where the material variables are obtained from experiments. The model novelty is in coupling mechanical, thermal, and irradiation damage through a consistent thermodynamic framework, including loss of thermal conductivity due to the evolution of mechanically induced micro-cracks. A number of thermo-mechanical experiments were conducted to confirm model assumptions. The model is shown to be validated with out-of-pile experiments, and then implemented using commercial finite element code COMSOL to the fuel cladding problem with normal and high radiation dose cases.

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