Nonlinear Analysis of RC Structures Using Isotropic Damage Model

2011 ◽  
Vol 21 (5) ◽  
pp. 647-669 ◽  
Author(s):  
Smitha Gopinath ◽  
J. Rajasankar ◽  
N. R. Iyer
Keyword(s):  
Damage Mechanics ◽  
Local Level ◽  
Damage Model ◽  
Coupled Model ◽  
Crack Model ◽  
Element Analysis ◽  
Directional Bias ◽  
Rc Structures ◽  
Isotropic Damage ◽  
As Stress

This article proposes a simple isotropic damage model within damage mechanics framework to represent the behavior of concrete in tension. Macroscopic evolution of tensile crack is considered as damage and is mathematically defined using an exponential function of tensile strain. A damage evolution law is formulated by applying strain equivalence principle to hyperbolic tension-softening curve. Value of damage variable is assumed theoretically to vary between ‘0’ and ‘1’ to denote uncracked and ruptured states, respectively. A smeared rotating crack model is coupled with damage formulation to simulate crack propagation effects in nonlinear finite element analysis of reinforced concrete (RC) structures. Many deficiencies of smeared crack model such as stress locking, mesh-induced directional bias, and instability in response computation for near-ultimate load are overcome using the coupled model. To verify the proposed model, nonlinear static response behavior of a RC beam is computed and compared with experimental and analytical results reported in literature. Effectiveness and applicability of the model to analyze practical structures are proved by analyzing a RC chimney. Nonlinear response of RC chimney is reviewed at global level while damage states of finite elements are studied at local level.

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 An efficient mechanical-probabilistic approach for the collapse modelling of RC structures

2019 ◽  
Vol 12 (2) ◽  
pp. 386-397
Author(s):  
K. O. COELHO ◽  
E. D. LEONEL ◽  
J. FLÓREZ-LÓPEZ
Keyword(s):  
Probabilistic Approach ◽  
Damage Model ◽  
Coupled Model ◽  
Simulation Method ◽  
Computationally Efficient ◽  
Rc Structures ◽  
Realistic Representation ◽  
Probabilistic Context ◽  
Numerical Approaches

Abstract The reinforced concrete (RC) structures are widely utilized around the world. However, the modelling of its complex mechanical behaviour by efficient numerical approaches has been presented marginally in the literature. The efficient approaches enable the accurate and the realistic representation of the mechanical phenomena involved and are computationally efficient for analysing complex structures. In the present study, the improved version of the lumped damage model is coupled to the Monte Carlo simulation method to represent the mechanical-probabilistic behaviour of RC structures. In such model, the concrete cracking and reinforcements’ yield are represented accurately. Moreover, this damage approach enables the accurate modelling of failure scenarios, which are based on the damage variable. Furthermore, this coupled model enables the determination of the collapse modelling accounting for uncertainties, which is the main contribution of the present study. One simple supported RC beam and one 2D RC frame are analysed in the probabilistic context. The accurate results are obtained for the probabilistic collapse path as well as its changes as a function of the loading conditions and material properties uncertainties.

scholarly journals Probabilistic Mesoscale Analysis of Concrete Beams Subjected to Flexure

2021 ◽  
Vol 26 (3) ◽  
pp. 12-27
Author(s):  
Haider M. Al-Jelawy ◽  
Ayad Al-Rumaithi ◽  
Aqeel T. Fadhil ◽  
Mohannad H. Al-Sherrawi
Keyword(s):  
Concrete Beams ◽  
Mesoscale Model ◽  
Damage Model ◽  
Nonlinear Behavior ◽  
Plain Concrete ◽  
Cumulative Probability ◽  
Crack Model ◽  
Softening Behavior ◽  
Model Response ◽  
Isotropic Damage

Abstract In this paper, the probabilistic behavior of plain concrete beams subjected to flexure is studied using a continuous mesoscale model. The model is two-dimensional where aggregate and mortar are treated as separate constituents having their own characteristic properties. The aggregate is represented as ellipses and generated under prescribed grading curves. Ellipses are randomly placed so it requires probabilistic analysis for model using the Monte Carlo simulation with 20 realizations to represent geometry uncertainty. The nonlinear behavior is simulated with an isotropic damage model for the mortar, while the aggregate is assumed to be elastic. The isotropic damage model softening behavior is defined in terms of fracture mechanics parameters. This damage model is compared with the fixed crack model in macroscale study before using it in the mesoscale model. Then, it is used in the mesoscale model to simulate flexure test and compared to experimental data and shows a good agreement. The probabilistic behavior of the model response is presented through the standard deviation, moment parameters and cumulative probability density functions in different loading stages. It shows variation of the probabilistic characteristics between pre-peak and post-peak behaviour of load-CMOD curves.

Influence of Aggregate Stiffness on Fracture-Mechanical Properties of Lime-Based Mortars

2013 ◽  
Vol 486 ◽  
pp. 289-294 ◽  
Author(s):  
Pavel Tesárek ◽  
Václav Nežerka ◽  
Pavel Padevět ◽  
Jakub Antoš ◽  
Tomáš Plachy
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Damage Model ◽  
Element Model ◽  
Stress Concentrations ◽  
Damage Development ◽  
Element Analysis ◽  
Three Point Bending ◽  
Isotropic Damage ◽  
The Finite Element Model

Addition of relatively stiff aggregates into lime-based mortars is responsible for an increase of the effective mortar stiffness and stress concentrations around aggregates during mechanical loading. To observe the damage development during the three-point bending and splitting tests a 2D plane-stress nonlinear finite element analysis utilizing isotropic damage model was carried out and the results were validated against experimentally obtained data. The study revealed that the finite element model is able to capture the trends observed during the experimental investigation. The results of the numerical modeling and experimental investigation show the advantages of the use of relatively compliant crushed brick aggregates in ancient structures.

Study on Excavation-Induced Permeability Changes in Clay Stone

2011 ◽  
Vol 243-249 ◽  
pp. 2548-2551
Author(s):  
Shan Po Jia ◽  
Wei Zhong Chen
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Coupled Model ◽  
Radioactive Waste Disposal ◽  
Self Healing ◽  
Shield Tunneling ◽  
Boom Clay ◽  
Permeability Changes ◽  
Damaged Zone ◽  
Clay Formation

The mechanical and hydraulic behavior of clay in the excavation damaged zone (EDZ) around underground repository is relevant for the assessment of the safety of geotechnical barriers. By integrating Mohr-Coulomb criterion and damage mechanics considerations, an elasto-plastic damage model is established for clay stone. Based on laboratory and in site investigations, the hydro-mechanical coupled damage model and permeability healing model is developed by the fully coupled hydro-mechanical coupled model, which can predict permeability changes and fractures self-healing in EDZ. Considering the construction of connecting gallery of radioactive waste disposal in deep clay formation in Belgium, a finite element damage model for simulating shield tunneling is proposed. The variations of damage and permeability around the tunnel with time are analyzed in detail. The proposed model is able to effectively depict the main features of hydro-mechanical behaviors of Boom clay.

Physically based damage models for laminated composites

2003 ◽  
Vol 217 (3) ◽  
pp. 163-199 ◽  
Author(s):  
L N McCartney
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Laminated Composites ◽  
Damage Model ◽  
Shear Loading ◽  
Analytical Models ◽  
Element Analysis ◽  
Plane Shear ◽  
Triaxial Loading ◽  
Physically Based

The computing power that is available for engineering calculation continues to grow at a dramatic pace. Engineers in industry want to have seamless models that can be used to design across the scale range from atoms to structures, including simulation of the manufacturing process. A limited aspect of this wish is the requirement to deal effectively with the progressive growth of microstructural damage in composites and its effect on both property degradation and the catastrophic failure event. This paper reviews progress that is being made at the National Physical Laboratory (NPL) with the development and validation of physically based damage growth models for laminated composites. The review includes: (a) prediction of undamaged ply properties determined from the properties of the fibre and the matrix, with emphasis on comparison of analytical models with each other, and with finite and boundary element solutions; (b) discussion of various stress transfer models, and their validation, that have been developed for application to the prediction of the properties of composite laminates having ply crack damage; (c) prediction of ply cracking in multiple-ply cross-ply laminates subject to triaxial loading (without shear) and bending; (d) prediction of ply cracking in general symmetric laminates subject to combined triaxial loading and in-plane shear loading; (e) consideration in a damage mechanics context of progressive ply crack formation in general symmetric laminates subject to thermal residual stresses and general in-plane loading, where an important new methodology is described that results from attempting to develop a continuum damage model from a physically based discrete ply cracking model based on energy concepts; (f) discussion of how the models might be integrated into finite element analysis (FEA) systems to enable strain softening in structures to be adequately modelled. The paper also includes statements concerning the status of the various models in relation to alternative approaches, and to model validation.

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.

scholarly journals Computational modelling of failure mechanisms in reinforced concrete structures

2010 ◽  
Vol 8 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Peter Mark ◽  
Michél Bender
Keyword(s):  
Reinforced Concrete ◽  
Damage Model ◽  
Computational Modelling ◽  
Flow Rule ◽  
Rc Structures ◽  
Suitable Material ◽  
Material Functions ◽  
Material Equations ◽  
Shear Beam ◽  
Isotropic Damage

A modelling approach for macroscopic reinforced concrete (RC) structures and structural elements under static loading conditions is presented. It uses the embedded modelling technique to separately account for concrete volumes and single longitudinal bars or stirrups. The material equations of the 3D elasto-plastic damage model for concrete are derived assuming isotropic damage, stiffness recovery and loss due to crack closing and reopening and a non-associated flow rule. Suitable material functions and material parameters as well as a regularisation by energy criteria are given. The approach is applied to shear beam tests illustrating numerical results compared to corresponding experimental data.

Effect of Residual Stress on the Mechanical Capacity of Layered Composite

2008 ◽  
Vol 368-372 ◽  
pp. 1803-1806
Author(s):  
Dae Suk Han ◽  
Chi Seung Lee ◽  
Min Sung Chun ◽  
Myung Hyun Kim ◽  
Hong Chae Park ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Damage Mechanics ◽  
Mechanical Performance ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Material Model ◽  
Layered Composite ◽  
Layered Composites ◽  
Element Analysis

For enhanced mechanical properties of ceramics for structural application, a great deal of attention has concentrated on preparation of layered composites. In this study, numerical simulation technique, which is applicable for the evaluation of mechanical performance for layered composite material, was developed. A generalized material constitutive equation coupled with material damage model based on the continuum damage mechanics approach was proposed and has been implemented to an in-house type finite element analysis code. The material behaviors for each component of layered composites can be simulated by the pre-defined material model on the simulation. A series of finite element analyses was carried out in order to elucidate the effect of fabrication related residual stress on the structural capacity of the layered composites.

scholarly journals Surface Settlement Damage Model of Pile-Anchor Supporting Structure in Deep Excavation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yuanxun Li ◽  
Wuyu Zhang ◽  
Ningshan Jiang ◽  
Hui Li
Keyword(s):  
Damage Mechanics ◽  
Damage Model ◽  
Surface Settlement ◽  
Skewed Distribution ◽  
Constitutive Relationship ◽  
Deep Excavation ◽  
Damage Development ◽  
Element Analysis ◽  
Undisturbed Soil ◽  
Damage Evolution Equation

In damage mechanics, the deep excavation of soil is a process of damage development, and soil failure can be considered a process of continuously transforming undisturbed soil to damaged soil. Therefore, this study considered the occurrence of soil damage during the pit excavation, established a soil damage model, damage evolution equation, and soil damage constitutive relationship, and then deduced a calculate model of the pile displacement under the consideration of soil damage. Based on the principle of the stratum loss method, the surface settlement around a deep excavated pit was assumed as a skewed distribution curve, and the surface settlement of the pile-anchor supporting pit was solved. Based on this established method, finite element analysis software was used to calculate the surface subsidence for a field case, and the numerical results were compared with monitoring data in the field. The results revealed that, to a certain extent, soil damage affected the distribution of surface settlement in excavated pits. With the development of soil damage, the mechanical properties of soil gradually decreased, which led to increased surface settlement and changes in the direction of the excavation pit. Because soil damage is an important factor causing surface settlement, it is meaningful to consider soil damage when calculating the surface settlement in the deep excavation of pits.

Sign in / Sign up

Export Citation Format

Share Document