scholarly journals 3D Anisotropic Elastoplastic-Damage Model and its Application in Simulating the Behavior of Rock Materials

2006 ◽  
Vol 324-325 ◽  
pp. 579-582
Author(s):  
Jun Feng Zhang ◽  
Tao Qi
Keyword(s):  
Damage Evolution ◽  
Damage Mechanics ◽  
Rock Sample ◽  
Progressive Failure ◽  
Failure Process ◽  
Damage Model ◽  
Tensor Decomposition ◽  
Continuum Damage Mechanics ◽  
Proposed Model ◽  
Elastoplastic Damage

A 3D anisotropic elastoplastic-damage model was presented based on continuum damage mechanics theory. In this model, the tensor decomposition technique is employed. Combined with the plastic yield rule and damage evolution, the stress tensor in incremental format is obtained. The derivate eigenmodes in the proposed model are assumed to be related with the uniaxial behavior of the rock material. Each eigenmode has a corresponding damage variable due to the fact that damage is a function of the magnitude of the eigenstrain. Within an eigenmodes, different damage evolution can be used for tensile and compressive loadings. This model was also developed into finite element code in explicit format, and the code was integrated into the well-known computational environment ABAQUS using the ABAQUS/Explicit Solver. Numerical simulation of an uniaxial compressive test for a rock sample is used to examine the performance of the proposed model, and the progressive failure process of the rock sample is unveiled.

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.

scholarly journals A bi-dissipative damage model for concrete

2015 ◽  
Vol 8 (1) ◽  
pp. 49-65
Author(s):  
J. J. C. Pituba ◽  
W. M. Pereira Júnior
Keyword(s):  
Reinforced Concrete ◽  
Structural Engineering ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Concrete Material ◽  
Framed Structures ◽  
Energy Equivalence ◽  
Proposed Model ◽  
Damage Processes

This work deals with an improvement of an anisotropic damage model in order to analyze reinforced concrete structures submitted to reversal loading. The original constitutive model is based on the fundamental hypothesis of energy equivalence between real and continuous media following the concepts of the Continuum Damage Mechanics. The concrete is assumed as an initial elastic isotropic medium presenting anisotropy, permanent strains and bimodularity induced by damage evolution. In order to take into account the bimodularity, two damage tensors governing the rigidity in tension or compression regimes are introduced. However, the original model is not capable to simulate the influence of the previous damage processes in compression regimes. In order to avoid this problem, some conditions are introduced to simulate the damage unilateral effect. It has noted that the damage model is agreement with to micromechanical theory conditions when dealing to unilateral effect in concrete material. Finally, the proposed model is applied in the analyses of reinforced concrete framed structures submitted to reversal loading. These numerical applications show the good performance of the model and its potentialities to simulate practical problems in structural engineering.

Material orthotropy effects on progressive damage analysis of open-hole composite laminates under tension

2017 ◽  
Vol 36 (20) ◽  
pp. 1473-1486 ◽  
Author(s):  
Song Zhou ◽  
Yi Sun ◽  
Boyang Chen ◽  
Tong-Earn Tay
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Tensile Loading ◽  
Progressive Damage ◽  
Cohesive Elements ◽  
Damage Initiation ◽  
Proposed Model ◽  
Open Hole

The sizes effects on the strengths of open-hole fibre-reinforced composite laminates subjected to tensile loading (OHT) have been investigated widely. However, little attention has been paid to the influence of material orthotropy. This paper presents a progressive damage model for the model failure of notched laminates under tensile loading based on continuum damage mechanics and cohesive elements. The effects of orthotropy on the failure of notched laminates with seven different ply sequences are investigated by our proposed model. The prediction results adopting the Hoffman and Pinho failure criterions to determine matrix damage initiation are compared with the results of experiments. Our proposed models are able to predict the strong influence of orthotropy on strengths of open-hole laminate under tension, and model using Pinho criterion can predict the open-hole tension strength most accurately.

Un modèle thermo-plastique couplé à l'endommagement pour le béton à hautes températures

2001 ◽  
Vol 28 (4) ◽  
pp. 593-607 ◽  
Author(s):  
Wahid Nechnech ◽  
Jean-Marie Reynouard ◽  
Fekri Meftah
Keyword(s):  
Damage Mechanics ◽  
Constitutive Relations ◽  
Damage Model ◽  
Thermal Action ◽  
Plain Concrete ◽  
Continuum Damage Mechanics ◽  
Mechanical Action ◽  
Proposed Model ◽  
Damage Theory ◽  
And Performance

In this paper a new thermoplastic damage model for plain concrete subjected to combined thermal and cyclic loading is developed using the concept of plastic-work hardening and stiffness degradation in continuum damage mechanics. Two damage variables are used: one for mechanical action and the other one for thermal action. Further, thermomechanical interaction strains have been introduced to describe the influence of mechanical loading on the physical process of thermal expansion of concrete. The constitutive relations for elastoplastic responses are decoupled from the degradation damage responses by using the effective stress concept. This method provides advantages in the numerical implementation. Efficient computational algorithms for the proposed model are subsequently explored and performance of this model is demonstrated with numerical examples.Key words: damage theory, plasticity, thermal, unilateral phenomenon, thermomechanical interaction.

A physically motivated model for fatigue damage of concrete

2017 ◽  
Vol 27 (8) ◽  
pp. 1192-1212 ◽  
Author(s):  
Ding Zhaodong ◽  
Li Jie
Keyword(s):  
Fatigue Damage ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Physical Mechanism ◽  
Crack Nucleation ◽  
Continuum Damage Mechanics ◽  
Self Similarity ◽  
Proposed Model ◽  
Damage Constitutive Model ◽  
Rate Process Theory

The fatigue problem of concrete is still a challenging topic in the researches and applications of concrete engineering. This paper aims to develop a fatigue damage evolution law based model for concrete motivated by the analysis of physical mechanism. In this model, the fatigue energy dissipation process at microscale is investigated with rate process theory. The concept of self-similarity is employed to bridge the scale gap between microscale cracking and mesoscale dissipative element. With the stochastic fracture model, the crack avalanches and macro-crack nucleation processes from mesoscale to macroscale are simulated to obtain the behaviors of macroscope damage evolution of concrete. In conjunction with continuum damage mechanics framework, the fatigue damage constitutive model for concrete is then proposed. Numerical simulations are carried out to verify the model, revealing that the proposed model accommodates well with physical mechanism of fatigue damage evolution of concrete whereby the fatigue life of concrete structures under different stress ranges can be predicted.

scholarly journals A Modified Fatigue Damage Model for High-Cycle Fatigue Life Prediction

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Meng Wang ◽  
Qingguo Fei ◽  
Peiwei Zhang
Keyword(s):  
Damage Mechanics ◽  
High Cycle Fatigue ◽  
Failure Process ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Cycle Fatigue ◽  
Damage State ◽  
Damage Evolution Equation ◽  
Metal Material ◽  
Python Language

Based on the assumption of quasibrittle failure under high-cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Then, finite element method (FEM) is used to describe the failure process of metal material. The increment of specimen’s life and damage state can be researched using damage mechanics-FEM. Finally, the lifetime of the specimen is got at the given stress level. The damage mechanics-FEM is inserted into ABAQUS with subroutine USDFLD and the Python language is used to simulate the fatigue process of titanium alloy specimens. The simulation results have a good agreement with the testing results under constant amplitude loading, which proves the accuracy of the method.

Constitutive Modeling of Damage Evolution in Semicrystalline Polyethylene

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
José A. Alvarado-Contreras ◽  
Maria A. Polak ◽  
Alexander Penlidis
Keyword(s):  
Amorphous Phase ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Texture Evolution ◽  
Continuum Damage Mechanics ◽  
Material Behavior ◽  
Phase Hardening ◽  
Strain Behavior ◽  
Proposed Model ◽  
Crystallographic Slip

In this article, the description of a novel damage-coupled constitutive formulation for the mechanical behavior of semicrystalline polyethylene is presented. The model attempts to describe the deformation and degradation processes in polyethylene considering the interplay between the amorphous and crystalline phases and following a continuum damage mechanics approach from a microstructural viewpoint. For the amorphous phase, the model is developed within a thermodynamic framework able to describe the features of the material behavior. Amorphous phase hardening is considered into the model and associated with the molecular configurations arising during the deformation process. The equation governing damage evolution is obtained by choosing a particular form based on internal energy and entropy. For the crystalline phase, the proposed model considers the deformation mechanisms by the theory of crystallographic slip and incorporates the effects of intracrystalline debonding and fragmentation. The model generated within this framework is used to simulate uniaxial tension and simple shear of high density polyethylene. The predicted stress-strain behavior and texture evolution are compared with experimental results and numerical simulations obtained from the literature. By incorporating a damage mechanics approach, the proposed model predicts the progressive loss of material stiffness attributed to the crystal fragmentation and molecular debonding of the crystal-amorphous interfaces.

A new damage-coupled cyclic plastic model for whole-life ratchetting of heat-treated U75V steel

2020 ◽  
Vol 29 (9) ◽  
pp. 1397-1415
Author(s):  
Ziyi Wang ◽  
Xiang Xu ◽  
Li Ding ◽  
Guozheng Kang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Fatigue Failure ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Hysteresis Loops ◽  
Continuum Damage Mechanics ◽  
Damage Evolution Equation ◽  
Plastic Model ◽  
Cyclic Plastic ◽  
Heat Treated ◽  
Proposed Model

In the framework of continuum damage mechanics, a new damage-coupled cyclic plastic model is proposed to describe the nonlinear evolution of whole-life ratchetting and its dependence on the stress level. The characteristic that the damage evolution rate of U75V heat-treated steel decays in the initial load cycles is considered by introducing a modified term into classic damage evolution equation. A hybrid fatigue failure criterion considering both the fatigue and ratchetting strain-induced failures is established based on the fatigue failure rule concluded from experiments. Comparisons between simulated and experimental stress–strain hysteresis loops, ratchetting strains, damage evolutions, and fatigue lives are performed to validate the proposed model.

Modelling Damage of Composite Laminates with Different Stacking Sequences

2013 ◽  
Vol 698 ◽  
pp. 1-10
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Numerical Application ◽  
Element Analysis

This paper considers damage development mechanisms in composite laminates subjected to tensile loading. The continuum damage mechanics is the most widely used approach to capture the non linear behaviour of laminates due to cracking. In this study, a continuum damage model based on ply failure criteria, which is initially proposed by Ladevèze has been extended to cover all plies failures mechanisms using an accurate numerical model to predict the equivalent damage accumulation. However, this model requires a reliable representation of the elementary damage mechanisms which can be produced in the composite laminate. To validate this model, a numerical application has been carried on the cross-ply laminates of type [0n/90m]s..A shear lag model was adapted to calculate the average stress of the 0° and 90° plies. The solution presented is obtained by using finite element analysis which implements progressive failure analysis. The effect of the stacking sequences has been done by varying the thickness of the 90° plies.

Fatigue Life of the Human Teeth: A Continuum Damage Approach

2019 ◽  
Vol 43 ◽  
pp. 1-19
Author(s):  
Theddeus Tochukwu Akano
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Stress Amplitude ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Elastoplastic Model ◽  
Human Teeth ◽  
Proposed Model ◽  
Number Of Cycles ◽  
Cycles To Failure

Normal oral food ingestion processes such as mastication would not have been possible without the teeth. The human teeth are subjected to many cyclic loadings per day. This, in turn, exerts forces on the teeth just like an engineering material undergoing the same cyclic loading. Over a period, there will be the creation of microcracks on the teeth that might not be visible ab initio. The constant formation of these microcracks weakens the teeth structure and foundation that result in its fracture. Therefore, the need to predict the fatigue life for human teeth is essential. In this paper, a continuum damage mechanics (CDM) based model is employed to evaluate the fatigue life of the human teeth. The material characteristic of the teeth is captured within the framework of the elastoplastic model. By applying the damage evolution equivalence, a mathematical formula is developed that describes the fatigue life in terms of the stress amplitude. Existing experimental data served as a guide as to the completeness of the proposed model. Results as a function of age and tubule orientation are presented. The outcomes produced by the current study have substantial agreement with the experimental results when plotted on the same axes. There is a notable difference in the number of cycles to failure as the tubule orientation increases. It is also revealed that the developed model could forecast for any tubule orientation and be adopted for both young and old teeth.

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