Damage Theoretical Analysis of 2.5D C/SiC Composites under Tensile and Shear Loading

2010 ◽  
Vol 150-151 ◽  
pp. 330-333
Author(s):  
Yan Jun Chang ◽  
Ke Shi Zhang ◽  
Gui Qiong Jiao ◽  
Jian Yun Chen
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Yield Function ◽  
Shear Loading ◽  
Isotropic Hardening ◽  
Shear Tests ◽  
Energy Equivalence ◽  
Damage Constitutive Model ◽  
Sic Composites ◽  
Nonlinear Hardening

An anisotropic damage constitutive model is developed to describe the damage behavior of C/SiC composites. Different kinematic and isotropic hardening functions were employed in damage yield function to describe accurately the damage nonlinear hardening. The damage variable is defined by the principle of energy equivalence. The degradation of stiffness and the unrecoverable deformation induced by micro-crack propagation were considered in this model. The constants of constitutive model are identified and the damage evolution processes under tensile and shear loading. Uniaxial tension and shear tests have been used to valid the constitutive model to C/SiC composites.

DUCTILE DAMAGE ANALYSIS BASED ON A J3-GTN-LIKE MODEL

2011 ◽  
Vol 03 (04) ◽  
pp. 189-215 ◽  
Author(s):  
LARBI SIAD
Keyword(s):  
Constitutive Model ◽  
Yield Function ◽  
Shear Loading ◽  
Isotropic Hardening ◽  
Single Element ◽  
Mapping Algorithm ◽  
Failure Initiation ◽  
Fully Implicit ◽  
Return Mapping ◽  
Return Mapping Algorithm

A GTN-like model which yield function explicitly depends upon the third stress invariant is first described in this paper. Subsequently, a fully implicit stress integration procedure of this constitutive model based on the return-mapping algorithm is developed. The validity and the performance of the implementation of the considered algorithm within a finite element code are checked through simulations of single element test and three-element test under hydrostatic tensile conditions and simple shear loading as well. Afterwards, as a numerical example, the presented constitutive model and, for the purpose of comparison, the GTN isotropic hardening model, are used to analyze the classical tensile test of axisymmetric notched specimens. The obtained results highlight similarities, good agreement between both models as long as failure initiation of specimen is not reached, and discrepancy as soon as failure of specimen starts.

Application and Analysis of Plane Woven C/SiC Composites Based on Continuum Damage Mechanics

2012 ◽  
Vol 490-495 ◽  
pp. 3916-3919 ◽  
Author(s):  
Yan Jun Chang ◽  
Ke Shi Zhang ◽  
Gui Qiong Jiao ◽  
Jian Yun Chen
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Kinematic Hardening ◽  
Ceramic Matrix Composites ◽  
Shear Loading ◽  
Internal Variables ◽  
Anisotropic Damage ◽  
Initial Modulus ◽  
Sic Composites

The aim of this article was to propose a macroscopic damage model, which describes the nonlinear behavior observed on woven C/SiC ceramic matrix composites. The model was built within a thermodynamic framework with internal variables. The anisotropic damage evolution processes of the material were described by nonlinear damage isotropic and kinematic hardening functions in this model. The anisotropic damage and damage coupling were considered with a damage yield function including anisotropic coefficients. Using the principle of energy equivalence, the damage variables were defined by the unloading modulus and initial modulus. The damage variable and the irrecoverable strain induced by micro-crack propagation were deduced by thermodynamics. The constants of constitutive model were identified and the damage evolution processes under tensile and shear loading. Uniaxial tension and shear tests had been used to valid the constitutive model to C/SiC composites.

A statistical damage constitutive model considering whole joint shear deformation

2020 ◽  
Vol 29 (6) ◽  
pp. 988-1008 ◽  
Author(s):  
Shijie Xie ◽  
Hang Lin ◽  
Yixian Wang ◽  
Yifan Chen ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Shear Stiffness ◽  
Rock Joints ◽  
Residual Phase ◽  
Proposed Model ◽  
Damage Constitutive Model ◽  
Damage Theory ◽  
Joint Shear ◽  
Statistical Damage

The whole shear deformation of rock joints significantly affects the long-term behavior and safety of engineering projects. In this paper, a new damage constitutive model related to the Weibull distribution and statistical damage theory is proposed. This model considers the shear stiffness degradation, post-peak softening, and residual phase of rock joints in the whole shearing process. Main works include the three following aspects: First, the phase of initial damage is determined on the assumption that the joint shear failure is regarded as a result of damage evolution, according to the typical joint shear curve and the three-parameter Weibull distribution. Then, a statistical damage evolution model for the whole joint shearing process is introduced to make this model be capable of describing the residual phase of rock joints. Finally, a statistical constitutive model for the whole joint shearing process is proposed by statistical damage theory, and the calculated results of the models are compared to the experimental results. The results indicate that the proposed model shows a good agreement with the experimental examples, and the proposed model can distinctly reflect the effects of residual stress, peak stress, and shear stiffness. In addition, the model parameters can be mathematically confirmed and have distinct physical meanings.

Constitutive Modeling for Impact Simulation of Random Fiber Composite Structures

1999 ◽  
Author(s):  
Haeng-Ki Lee ◽  
Srdan Simunovic
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Structures ◽  
Fiber Composite ◽  
Damage Model ◽  
Yield Function ◽  
Progressive Damage ◽  
Finite Element Code ◽  
Effective Yield ◽  
Damage Constitutive Model

Abstract A constitutive model for progressive crushing is presented to predict impact behavior and damage evolution in random carbon fiber polymer matrix composites (RCFPMCs). Based on the ensemble-volume averaging process and first-order effects of eigenstrains due to the existence of prolate fibers, an effective yield criterion is derived to estimate the overall elastoplastic damage responses. First, an effective elastoplastic constitutive damage model for aligned fiber-reinforced composites is proposed. A micromechanical damage constitutive model for RCFPMCs is then developed. The governing field equations and overall yield function for aligned fiber-orientations are averaged over all orientations to obtain the constitutive relations and effective yield function of RCFPMCs. Finally, the complete progressive damage constitutive model is implemented into finite element code DYNA3D to solve large scale problems such as automobile components and systems. An advantage of the progressive damage analysis is that the information from the progressive damage model can be implemented into finite element code as material input properties and thus the calculations required in the constitutive model can be greatly reduced.

Three-dimensional elastic-plastic damage constitutive model of wood

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Lipeng Zhang ◽  
Qifang Xie ◽  
Baozhuang Zhang ◽  
Long Wang ◽  
Jitao Yao
Keyword(s):  
Constitutive Model ◽  
Damage Mechanics ◽  
Euler Method ◽  
Isotropic Hardening ◽  
Damage Initiation ◽  
Elastic Plastic ◽  
Plastic Damage ◽  
Backward Euler ◽  
Tension And Compression ◽  
Damage Constitutive Model

AbstractA 3D combined elastic-plastic damage constitutive model for wood is proposed within the theoretical framework of classical plasticity and continuum damage mechanics (CDM). The model is able to describe the various behavior of wood under loading, including the orthotropic elasticity, strengths inequality under tension and compression in each orthotropic direction, ductile softening under longitudinal compression, brittle failure under transverse tension, and parallel shearing, densification hardening under transverse compression. Hoffman criterion and a set of eight separate failure criteria were used to define wood yielding and damage initiation, respectively. Isotropic hardening was assumed after yielding and defined by an exponential type function. The constitutive model was implicitly discretized using backward Euler method, solved through the return mapping algorithm and implemented into ABAQUS through the user-defined material subroutine (UMAT). The proposed model was firstly verified by material property tests considering different stress states: monotonic and repeated tension and compression (in both parallel and perpendicular-to-grain directions), parallel-to-grain shearing, and the interactions between perpendicular-to-grain compression/tension and parallel-to-grain shearing, etc. Mechanical behavior of typical structural elements was further simulated to validate the proposed constitutive model.

scholarly journals Damage constitutive model of pure copper at different annealing temperatures

2021 ◽  
Vol 2045 (1) ◽  
pp. 012013
Author(s):  
L Li ◽  
X J Zhu ◽  
L Zhang ◽  
F Z Tian
Keyword(s):  
Constitutive Model ◽  
Shape Factor ◽  
Damage Evolution ◽  
Annealing Temperature ◽  
Tensile Deformation ◽  
Pure Copper ◽  
Annealing Temperatures ◽  
Damage Constitutive Model ◽  
Evolution Behavior ◽  
Hardening Coefficient

Abstract Aiming at the problem of damage evolution of pure copper during the plastic deformation, the normalized shape factor is introduced based on the RO model (Ramberg-Osgood model). The mesoscopic damage constitutive model of pure copper at different annealing temperatures is established and the tensile deformation of industrial pure copper at different annealing temperatures is analyzed. The results show that the error between the calculated value and the experimental value of the damage constitutive model, based on normalized shape factor, at different annealing temperatures, is less than 10%. The model can effectively reveal the tensile damage evolution behavior of industrial pure copper and accurately predict the plastic tensile flow stress of industrial pure copper at different annealing temperatures. The hardening coefficient and hardening exponent in the model are closely related to the annealing temperature of the material. The annealing temperature has little effect on the hardening exponent and has a significant effect on the hardening coefficient and the hardening coefficient decreases with the increase in annealing temperature.

scholarly journals A Statistical Damage Constitutive Model of Anisotropic Rock: Development and Validation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Tenglong Rong ◽  
Can Guan ◽  
Keliu Liu ◽  
Shuai Heng ◽  
Wenlong Shen ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Stress Conditions ◽  
Anisotropic Damage ◽  
Anisotropic Rock ◽  
Stress Strain ◽  
True Triaxial ◽  
Damage Constitutive Model ◽  
Statistical Damage Constitutive Model ◽  
Statistical Damage

The damage constitutive model is of great significance to research the stress-strain relationship and damage evolution of rock under loading in engineering. In order to investigate the effect of anisotropic characteristic on the stress-strain relationship and damage evolution, a statistical damage constitutive model of anisotropic rock under true triaxial condition was developed. In this study, the plane which existed perpendicular to the coordinate axis was extracted from representative volume element (RVE) of rock. The extracted plane was assumed to be composed of abundant mesoscopic elements whose failure strength satisfied the Weibull distribution. According to the number of failure elements on the plane in each direction under loading, the anisotropic damage variable was established based on the proposed concept of areal damage. A statistical damage constitutive model of anisotropic rock was developed by using strain equivalent hypothesis and generalized Hooke constitutive model. Subsequently, the parameters in the anisotropic damage constitutive model were determined by the method of total differential. Thus, the damage evolution of anisotropic rock under various stress conditions can be conveniently evaluated by the anisotropic damage model. The model was validated based on the tests of rocks under the stress conditions of conventional triaxial and true triaxial, respectively. Moreover, for the purpose of studying the influence of parameters on the model, sensitivity analyses of mechanical parameters and model parameters were carried out. The results of statistical damage constitutive clearly demonstrate the stress-strain and damage evolution of anisotropic rock under various stress conditions.

scholarly journals Study on Damage Constitutive Model of High-Concentration Cemented Backfill in Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baogui Yang ◽  
Haigang Yang
Keyword(s):  
Constitutive Model ◽  
Coal Mine ◽  
Damage Evolution ◽  
Triaxial Compression ◽  
Failure Process ◽  
Model Parameters ◽  
High Concentration ◽  
Deformation And Failure ◽  
Cemented Backfill ◽  
Damage Constitutive Model

In order to construct the damage constitutive model (DCM) of high-concentration cemented backfill (HCCB) in coal mine, the generalized Hoek-Brown strength criterion was used as the failure criterion. For the difference of theoretical derivation of constitutive relation, a new DCM based on residual strength was proposed. Combined with the conventional triaxial compression test, the correctness and rationality of the DCM were verified. The damage evolution characteristics of HCCB were analyzed, and the physical meaning of model parameters was clarified. The results show that (a) the theoretical curves of stress-strain relation are in good agreement with its experimental curves, which means DCM can simulate the deformation and failure process of HCCB. (b) The damage evolution curve of HCCB is S -shaped. To some extent, the confining pressure can inhibit the development of damage. (c) The parameter F 0 reflects the position of the peak point of the DCM, and parameter n is the slope of the straight line segment in the postpeak strain softening stage, which are, respectively, used to characterize the strength level and brittleness of HCCB. The establishment of DCM of HCCB is helpful to reveal its deformation and failure mechanism and provides theoretical basis for its strength design.

Thermo-mechanical coupling damage constitutive model of rock based on the Hoek–Brown strength criterion

2017 ◽  
Vol 27 (8) ◽  
pp. 1213-1230 ◽  
Author(s):  
Xiaoli Xu ◽  
Feng Gao ◽  
Zhizhen Zhang
Keyword(s):  
Constitutive Model ◽  
Damage Evolution ◽  
Mechanical Response ◽  
Peak Stress ◽  
Strength Criterion ◽  
Confining Pressure ◽  
Stress Strain ◽  
Mechanical Coupling ◽  
Damage Stability ◽  
Damage Constitutive Model

Studying the thermal damage constitutive model of rock using statistical theory can better reflect the damage evolution process and the stress–strain relationship of rock under temperature and loading, which is one of the key problems especially in deep rock mechanics. The thermal-mechanical coupling damage constitutive model of rock is established using the Hoek–Brown strength criterion, based on the Weibull distribution and the continuous damage theory. The rationality of the model is also verified by experiments. The main conclusions are as follows. The stress–strain curves of rock can be divided into four stages according to the damage evolution characteristics, including the non-damage of loading, damage stability expansion, damage intensification expansion, and damage stability expansion to saturation, and the method of determining the demarcation points of each stage is given clearly. The initial damage point of the rock is about 25% of the peak stress, the damage value is about 0.3 when the rock reaches the peak stress and about 0.6 when reaches the residual stress. Both the damage value and the strain energy release rate of the rock corresponding to the peak stress show exponential growth with the increase in confining pressure. The maximum damage evolution rate of the rock shows exponential decay as the confining pressure rises, indicating that the confining pressure can delay the development of cumulative damage. The modified damage constitutive model considering compaction coefficient is in good agreement with the test curves in the stage of compaction, linear elasticity, yield, and pre-peak strength. It is hoped that through the research of this paper, it can provide references for studying the macroscopic mechanical response from the damage propagation characteristics of the rock in the future.

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