scholarly journals Computational Modelling of Fracture Propagation in Rocks Using a Coupled Elastic-Plasticity-Damage Model

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Isa Kolo ◽  
Rashid K. Abu Al-Rub ◽  
Rita L. Sousa
Keyword(s):  
Constitutive Model ◽  
Damage Model ◽  
Computational Modelling ◽  
Fracture Propagation ◽  
Material Model ◽  
Model Predictions ◽  
Tension And Compression ◽  
Damage Constitutive Model ◽  
Ak Model ◽  
Spatially Varying

A coupled elastic-plasticity-damage constitutive model, AK Model, is applied to predict fracture propagation in rocks. The quasi-brittle material model captures anisotropic effects and the distinct behavior of rocks in tension and compression. Calibration of the constitutive model is realized using experimental data for Carrara marble. Through the Weibull distribution function, heterogeneity effect is captured by spatially varying the elastic properties of the rock. Favorable comparison between model predictions and experiments for single-flawed specimens reveal that the AK Model is reliable and accurate for modelling fracture propagation in rocks.

Multi-Axial Concrete Models for Nonlinear Analysis

2014 ◽  
Vol 1065-1069 ◽  
pp. 2099-2103
Author(s):  
Hu Qi ◽  
Yun Gui Li
Keyword(s):  
Constitutive Model ◽  
Nonlinear Analysis ◽  
Damage Model ◽  
Nonlinear Characteristic ◽  
Plastic Model ◽  
Elastic Plastic ◽  
Plastic Damage ◽  
Damage Constitutive Model

The most widely used multi-axial concrete models including elastic-plastic model and elastic plastic damage model are expounded and it is recognized that the elastic plastic damage model is more reasonable to reflect nonlinear characteristic of concrete. The development and application of elastic plastic damage model is comprehensively appraised and a practical elastic plastic damage constitutive model is established. Finally the dynamic trend of constitutive model of concrete development is introduced.

Statistical Damage Constitutive Model for Concrete under Biaxial Tension

2013 ◽  
Vol 438-439 ◽  
pp. 183-186
Author(s):  
Wei Feng Bai ◽  
Jun Hong Zhang ◽  
Jun Feng Guan ◽  
Ying Cui
Keyword(s):  
Constitutive Model ◽  
Biaxial Tension ◽  
Damage Model ◽  
Damage Mechanism ◽  
Deformation Properties ◽  
Damage Constitutive Model ◽  
Strength And Deformation ◽  
Statistical Damage Constitutive Model ◽  
Damage Theory ◽  
Statistical Damage

Based on the statistical damage theory and the experimental phenomena, the statistical damage constitutive model for concrete under biaxial tension is proposed. The two meso-scale damage modes, rupture and yield are considered, and the whole damage evolution process is driven by the principal tensile damage strain. The results show that the proposed statistical damage model can accurately predict the constitutive behavior in the uniform damage phase for concrete under biaxial tension. The damage mechanism is discussed in the view point of biaxial strength and deformation properties.

scholarly journals A Multiparameter Damage Constitutive Model for Rock Based on Separation of Tension and Shear

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
YanHui Yuan ◽  
Ming Xiao
Keyword(s):  
Constitutive Model ◽  
Damage Model ◽  
Damage Mechanism ◽  
Internal Variable ◽  
Damage Variable ◽  
Tensor Form ◽  
Shear Damage ◽  
Damage Constitutive Model ◽  
Microscopic Damage ◽  
Elastoplastic Damage

By analysis of the microscopic damage mechanism of rock, a multiparameter elastoplastic damage constitutive model which considers damage mechanism of tension and shear is established. A revised general form of elastoplastic damage model containing damage internal variable of tensor form is derived by considering the hypothesis that damage strain is induced by the degeneration of elastic modulus. With decomposition of plastic strain introduced, the forms of tension damage variable and shear damage variable are derived, based on which effects of tension and shear damage on material’s stiffness and strength are considered simultaneously. Through the utilizing of Zienkiewicz-Pande criterion with tension limit, the specific form of the multiparameter damage model is derived. Numerical experiments show that the established model can simulate damage behavior of rock effectively.

STOCHASTIC VISCOUS-DAMAGE CONSTITUTIVE MODEL FOR CONCRETE

2013 ◽  
Vol 07 (03) ◽  
pp. 1350027
Author(s):  
JIE LI ◽  
QIAOPING HUANG
Keyword(s):  
Damage Model ◽  
Damage Mechanism ◽  
Failure Behavior ◽  
Strain Rates ◽  
Rate Dependency ◽  
Rate Dependent ◽  
Proposed Model ◽  
Model Predictions ◽  
Damage Constitutive Model ◽  
Stochastic Damage

A new rate-dependent stochastic damage model for the dynamic modeling of concrete is presented in the paper. This model is formulated on the basis of the stochastic damage model, from which, the static stochastic evolution of damage is strictly derived. Then, rate dependency of concrete is included by means of viscous-damage mechanism. The model predictions are tested against experimental results on concrete specimens that cover different strain rates. The results demonstrate the proposed model may predict dynamic failure behavior of concrete quite well.

Stochastic Damage Constitutive Model for Concrete Subjected to Uniaxial Tension Stress

2009 ◽  
Vol 417-418 ◽  
pp. 921-924
Author(s):  
Ming Xie ◽  
Shan Suo Zheng ◽  
Bin Wang ◽  
Lei Li ◽  
Wei Wang
Keyword(s):  
Constitutive Model ◽  
Uniaxial Tension ◽  
Experimental Situation ◽  
Failure Process ◽  
Damage Model ◽  
Tension Stress ◽  
Calculation Results ◽  
Concrete Damage ◽  
Damage Constitutive Model ◽  
Stochastic Damage

A stochastic damage constitutive model is proposed based on Kelvin spring-damper model and Li Jie spring stochastic damage model. The model is made up by microscopic spring-slipper element. The slipper, parallel connected with spring, is introduced to consider the plasticity effect of concrete. Damage failure process of concrete subjected uniaxial tension is divided into spring broken state and slipper broken state to describe the elastic stage and plastic stage of damage respectively. In the light of energy conservation during the process of damage failure, stochastic damage constitutive equation of concrete material subjected to uniaxial tension stress is derived. Comparisons between test results and theoretical calculation results verify that the established constitutive damage equations are accord with the experimental situation, and the experimental data are observed undulated with theoretical curve in the range of variance. The research results can apply in the actual engineering.

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.

Statistical damage model with strain softening and hardening for rocks under the influence of voids and volume changes

2010 ◽  
Vol 47 (8) ◽  
pp. 857-871 ◽  
Author(s):  
Wen-Gui Cao ◽  
Heng Zhao ◽  
Xiang Li ◽  
Yong-Jie Zhang
Keyword(s):  
Constitutive Model ◽  
Strain Softening ◽  
Triaxial Compression ◽  
Damage Model ◽  
Damage Threshold ◽  
Model Parameters ◽  
Volume Changes ◽  
Conventional Triaxial Compression ◽  
Damage Constitutive Model ◽  
Statistical Damage

With regards to the composition of natural rocks including voids or pores, deformation behavior is strongly affected by variation in porosity. By using a statistical damage-based approach, the characteristics of strain softening and hardening under the influence of voids and volume changes are investigated in the present paper. Suppose that a rock consists of three parts: voids, a damaged part, and an undamaged part. The effects of voids and volume changes on rock behavior are first analyzed through determination of the porosity and an associated damage model is then developed. Later, a statistical evolution equation describing the influence of the damage threshold on the propagation condition of rock damage is formulated based on measurement of the mesoscopic element strength. A statistical damage constitutive model reflecting strain softening and hardening behavior for rocks loaded in conventional triaxial compression is further developed and a corresponding method for determining the model parameters is also provided. Theoretical results of this proposed model are then compared with those observed experimentally. Finally, several aspects of the present constitutive model, which affect the relevant behavior of rocks, are particularly discussed.

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 On the Kachanov-Rabotnov continuum damage model

2020 ◽  
Vol 53 (2) ◽  
pp. 125-144
Author(s):  
Harm Askes ◽  
Juha Hartikainen ◽  
Kari Kolari ◽  
Reijo Kouhia ◽  
Timo Saksala ◽  
...  
Keyword(s):  
Free Energy ◽  
Constitutive Model ◽  
Tensile Test ◽  
Helmholtz Free Energy ◽  
Damage Model ◽  
Continuum Damage ◽  
Dissipation Potential ◽  
Continuum Damage Model ◽  
Damage Constitutive Model ◽  
Basic Features

In this paper two partially complementary formulations of the simple phenomenological Kachanov-Rabotnov continuum damage constitutive model are presented. The models are based on a consistent thermodynamic formulation using proper expressions for the Helmholtz free energy or its complementary form of the dissipation potential. Basic features of the models are discussed and the behaviour in tensile test and creep problems is demonstrated.

scholarly journals A Creep Damage Constitutive Model for a Rock Mass with Nonpersistent Joints under Uniaxial Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shuran Lv ◽  
Wanqing Wang ◽  
Hongyan Liu
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Mechanical Behavior ◽  
Uniaxial Compression ◽  
Damage Model ◽  
Creep Damage ◽  
Model Parameters ◽  
Damage Constitutive Model ◽  
Set Up ◽  
Creep Damage Model

As part of the rock mass, both the mesoscopic and macroscopic flaws will affect the creep mechanical behavior of the rock mass with nonpersistent joints. This study focuses on this kind of rock mass and establishes a creep damage model to account for the effect of the joint on its creep mechanical behavior. First, on basis of analyzing the rock element creep mechanism and the typical creep deformation curve, a new creep damage constitutive model for the rock element is set up by introducing the damage theory and Kachanov damage evolution law into the classic creep constitutive model such as J body model. Second, the determination method of the proposed model parameters is studied in detail. Third, the calculation method of the macroscopic damage caused by the joint proposed by others is introduced which can consider the joint geometry, strength, and deformation parameters at the same time. Finally, the creep damage model for the rock mass with nonpersistent joints under uniaxial compression is proposed. The calculation examples indicate that it can present the effect of the joint on the rock mass creep mechanical behavior.

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