Development and Numerical Implementation of an Anisotropic Continuum Damage Model for Concrete

2016 ◽  
Vol 713 ◽  
pp. 115-118
Author(s):  
Juha Hartikainen ◽  
Kari Kolari ◽  
Reijo Kouhia
Keyword(s):  
Basic Characteristic ◽  
Damage Model ◽  
Failure Surface ◽  
Anisotropic Damage ◽  
Continuum Damage ◽  
Numerical Implementation ◽  
Dissipation Potential ◽  
Characteristic Behaviour ◽  
Gibb’S Free Energy ◽  
Realistic Shape

In this paper, a thermodynamic formulation for modelling anisotropic damage of elastic-brittle materials based on Ottosen's 4-parameter failure surface is proposed. The model is developed by using proper expressions for Gibb's free energy and the complementary form of the dissipation potential. The formulation predicts the basic characteristic behaviour of concrete well and results ina realistic shape for the damage surface.

Failure Predictions for DP Steel Cross-die Test using Anisotropic Damage

2011 ◽  
Vol 21 (5) ◽  
pp. 713-754 ◽  
Author(s):  
M. S. Niazi ◽  
H. H. Wisselink ◽  
T. Meinders ◽  
J. Huétink
Keyword(s):  
Strain Rate ◽  
Damage Evolution ◽  
Damage Model ◽  
Anisotropic Damage ◽  
Continuum Damage ◽  
Anisotropic Plasticity ◽  
Continuum Damage Model ◽  
Damage Models ◽  
Isotropic Damage ◽  
Failure Predictions

The Lemaitre's continuum damage model is well known in the field of damage mechanics. The anisotropic damage model given by Lemaitre is relatively simple, applicable to nonproportional loads and uses only four damage parameters. The hypothesis of strain equivalence is used to map the effective stress to the nominal stress. Both the isotropic and anisotropic damage models from Lemaitre are implemented in an in-house implicit finite element code. The damage model is coupled with an elasto-plastic material model using anisotropic plasticity (Hill-48 yield criterion) and strain-rate dependent isotropic hardening. The Lemaitre continuum damage model is based on the small strain assumption; therefore, the model is implemented in an incremental co-rotational framework to make it applicable for large strains. The damage dissipation potential was slightly adapted to incorporate a different damage evolution behavior under compression and tension. A tensile test and a low-cycle fatigue test were used to determine the damage parameters. The damage evolution was modified to incorporate strain rate sensitivity by making two of the damage parameters a function of strain rate. The model is applied to predict failure in a cross-die deep drawing process, which is well known for having a wide variety of strains and strain path changes. The failure predictions obtained from the anisotropic damage models are in good agreement with the experimental results, whereas the predictions obtained from the isotropic damage model are slightly conservative. The anisotropic damage model predicts the crack direction more accurately compared to the predictions based on principal stress directions using the isotropic damage model. The set of damage parameters, determined in a uniaxial condition, gives a good failure prediction under other triaxiality conditions.

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.

Use of a Continuum Damage Model Based on Energy Equivalence to Predict the Response of a Single-Crystal Superalloy

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
P. Grammenoudis ◽  
D. Reckwerth ◽  
Ch. Tsakmakis
Keyword(s):  
Equivalence Principle ◽  
Evolution Equations ◽  
Dynamic Recovery ◽  
Damage Model ◽  
Yield Function ◽  
Anisotropic Damage ◽  
Continuum Damage ◽  
Energy Equivalence ◽  
Deformation Processes ◽  
Multiple Holes

Anisotropic viscoplasticity coupled with anisotropic damage has been modeled in previous works by using the energy equivalence principle appropriately adjusted. Isotropic and kinematic hardenings are present in the viscoplastic part of the model and the evolution equations for the hardening variables incorporate both static and dynamic recovery terms. The main difference to other approaches consists in the formulation of the energy equivalence principle for the plastic stress power and the rate of hardening energy stored in the material. As a practical consequence, a yield function has been established, which depends, besides effective stress variables, on specific functions of damage. The present paper addresses the capabilities of the model in predicting responses of deformation processes with complex specimen geometry. In particular, multiple notched circular specimens and plates with multiple holes under cyclic loading conditions are considered. Comparison of predicted responses with experimental results confirms the convenience of the proposed theory for describing anisotropic damage effects.

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.

Modified Dyson Continuum Damage Model for Austenitic Steel Alloy

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Seok Jun Kang ◽  
Hoomin Lee ◽  
Jae Boong Choi ◽  
Moon Ki Kim
Keyword(s):  
Damage Model ◽  
Life Time ◽  
Continuum Damage ◽  
Creep Life ◽  
Creep Tests ◽  
Continuum Damage Model ◽  
Thermal Plant ◽  
Uniaxial Creep ◽  
Term Creep

Ultrasuper critical (USC) thermal plants are now in operation around the globe. Their applications include superheaters and reheaters, which generally require high temperature/pressure conditions. To withstand these harsh conditions, an austenitic heat-resistant HR3C (ASME TP310NbN) steel was developed for metal creep resistance. As the designed life time of a typical thermal plant is 150,000 h, it is very important to predict long-term creep behavior. In this study, a three-state variable continuum damage model (CDM) was modified for better estimation of long-term creep life. Accelerated uniaxial creep tests were performed to determine the material parameters. Also, the rupture type and microstructural precipitation were observed by scanning electron microscopy. The creep life of HR3C steel was predicted using only relatively short-term creep test data and was then successfully verified by comparison with the long-term creep data.

Comparison of Two Time-Integration Algorithms for an Anisotropic Damage Model Coupled with Plasticity

2015 ◽  
Vol 784 ◽  
pp. 292-299 ◽  
Author(s):  
Stephan Wulfinghoff ◽  
Marek Fassin ◽  
Stefanie Reese
Keyword(s):  
Evolution Equations ◽  
Damage Model ◽  
Time Integration ◽  
Three Dimensional ◽  
Anisotropic Damage ◽  
Euler Scheme ◽  
The Finite Element Method ◽  
Time Step ◽  
Implicit Euler Scheme ◽  
Integration Algorithms

In this work, two time integration algorithms for the anisotropic damage model proposed by Lemaitre et al. (2000) are compared. Specifically, the standard implicit Euler scheme is compared to an algorithm which implicitly solves the elasto-plastic evolution equations and explicitly computes the damage update. To this end, a three dimensional bending example is solved using the finite element method and the results of the two algorithms are compared for different time step sizes.

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