Continuum Damage Mechanics Studies on the Dynamic Fracture of Concrete

1985 ◽  
Vol 64 ◽  
Author(s):  
E. P. Chen
Keyword(s):  
Dynamic Fracture ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Damage Mechanism ◽  
Continuum Damage ◽  
Strain Rate Effects ◽  
Perfectly Plastic ◽  
Material Stiffness ◽  
Elastic Perfectly Plastic

ABSTRACTThe dynamic fracture of concrete in tension is studied by applying a continuum damage model developed by the author and his coworkers [1–3]. In this model, the degree of damage in concrete corresponds to the fraction of concrete volume that has been tension relieved, and tensile microcracking has been taken as the damage mechanism. In compression, the concrete is assumed to respond in an elastic/perfectly plastic manner. Strain-rate effects have been explicitly included in the model. Accumulation of damage in the material is reflected by the progressive weakening of the material stiffness. Examples involving center- and edge-cracked plate specimens subjected to the action of step and ramp loads are used to demonstrate the material responses predicted by the model. The bulk pressure versus strain relationships at locations close to the crack tip clearly show strainsoftening behavior. The damage tends to localize around the crack and its extent in the specimen is dependent upon both the crack geometry and the loading type. These results are presented and their implications are discussed.

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.

Stochastic Continuum Damage Mechanics Using Spring Lattice Models

2015 ◽  
Vol 784 ◽  
pp. 350-357 ◽  
Author(s):  
Sohan Kale ◽  
Seid Koric ◽  
Martin Ostoja-Starzewski
Keyword(s):  
Damage Mechanics ◽  
Lattice Models ◽  
Continuum Damage Mechanics ◽  
Constitutive Law ◽  
Disordered Media ◽  
Length Scale ◽  
Continuum Damage ◽  
Perfectly Plastic ◽  
Discrete Nature ◽  
Plastic Responses

In this study, a planar spring lattice model is used to study the evolution of damage variabledLin disordered media. An elastoplastic softening damage constitutive law is implemented which introduces a cohesive length scale in addition to the disorder-induced one. The cohesive length scale affects the macroscopic response of the lattice with the limiting cases of perfectly brittle and perfectly plastic responses. The cohesive length scale is shown to affect the strength-size scaling such that the strength increases with increasing cohesive length scale for a given size. The formation and interaction of the microcracks is easily captured by the inherent discrete nature of the model and governs the evolution ofdL. The proposed method provides a way to extract a mesoscale dependent damage evolution rule that is linked directly to the microstructural disorder.

Characterization of Notched Ductile Failure With Continuum Damage Mechanics

1990 ◽  
Vol 112 (4) ◽  
pp. 412-421 ◽  
Author(s):  
C. L. Chow ◽  
K. Y. Sze
Keyword(s):  
Ductile Fracture ◽  
Circular Hole ◽  
Damage Mechanics ◽  
Damage Model ◽  
Ductile Failure ◽  
Continuum Damage Mechanics ◽  
Thin Plates ◽  
Continuum Damage ◽  
Anisotropic Model ◽  
Aluminum Alloy 2024

A recently developed anisotropic model of continuum damage mechanics has been applied successfully to characterize ductile fracture of cracked plates under mode I and mixed mode failures. The damage model is further extended in this investigation to examine its applicability to include notch ductile fracture of thin plates containing a circular hole. Two hole sizes of 16 mm and 24 mm diameters are chosen and the specimen material is aluminum alloy 2024-T3. Fracture loads of the plates are predicted by the damage model and compared satisfactorily with those determined experimentally. This investigation provides an important confirmation that not only the anisotropic model of continuum damage mechanics but also the same failure criterion developed can be effectively employed to characterize both ductile fracture for plates containing an isolated macro-crack or circular hole which would otherwise not be possible using the conventional theory of fracture mechanics. The successful development of the unified approach to characterize ductile failure provides a vital impetus for design engineers in the general application of the theory of continuum damage mechanics to solve practical engineering problems.

CONTINUUM DAMAGE MECHANICS ANALYSIS OF THIN-WALLED TUBE UNDER CYCLIC BENDING AND INTERNAL CONSTANT PRESSURE

2013 ◽  
Vol 05 (04) ◽  
pp. 1350038 ◽  
Author(s):  
H. YAZDANI ◽  
A. NAYEBI
Keyword(s):  
Internal Pressure ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Cyclic Bending ◽  
Thin Walled Tube ◽  
Thin Walled

Ratcheting and fatigue damage of thin-walled tube under cyclic bending and steady internal pressure is studied. Chaboche's nonlinear kinematic hardening model extended by considering the effect of continuum damage mechanics employed to predict ratcheting. Lemaitre damage model [Lemaitre, J. and Desmorat, R. [2005] Engineering Damage Mechanics (Springer-Verlag, Berlin)] which is appropriate for low cyclic loading is used. Also the evolution features of whole-life ratcheting behavior and low cycle fatigue (LCF) damage of the tube are discussed. A simplified method related to the thin-walled tube under bending and internal pressure is used and compared well with experimental results. Bree's interaction diagram with boundaries between shakedown and ratcheting zone is determined. Whole-life ratcheting of thin-walled tube reduces obviously with increase of internal pressure.

The Frost Model of Concrete in the View of Damage Mechanics

2011 ◽  
Vol 194-196 ◽  
pp. 919-923 ◽  
Author(s):  
Dong Fang Pan ◽  
Yun Feng Qiao ◽  
Cheng Shuai Sun ◽  
Xue Bing Liu
Keyword(s):  
Plastic Deformation ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Dissipation Function ◽  
Continuum Damage ◽  
Thawing Cycle ◽  
Frost Model ◽  
Elastic Modules ◽  
The Continuum

To propose the damage model of concrete in the freezing-thawing cycles, the reasonable dissipation function and micro plastic deformation expression have been determined based on the continuum damage mechanics. The damage variable is expressed as a function of the number of freezing-thawing cycle. The damage is defined in terms of the loss of the dynamic elastic modules and the damage model of the concrete in the freezing-thawing cycles has been presented.

Elastic Ply Damage Mechanics Modeling of Glass/Epoxy Laminated Composite

2013 ◽  
Vol 683 ◽  
pp. 176-181
Author(s):  
Yong Chen ◽  
Bao Jun Pang ◽  
Wei Zheng
Keyword(s):  
Composite Material ◽  
Damage Mechanics ◽  
Epoxy Composite ◽  
Damage Model ◽  
Laminated Composite ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Tensile Shear ◽  
Mechanics Model ◽  
Input Parameters

In order to establish an elastic damage model for S2-glass/epoxy composite and identify the input parameters, in-plane behaviour of the composite including tensile, compression and tensile shear were investigated through series of tests. Concerning no plasticity, a simple elastic ply damage mechanics model for this composite was characterized based on Continuum Damage Mechanics Model (CDM) and the input parameters were obtained. The model was then implemented into ABAQUS/EXPLICT and the results show the model can capture most of the in-plane behaviour of the composite material.

Fatigue and fretting fatigue life prediction of double-lap bolted joints using continuum damage mechanics-based approach

2016 ◽  
Vol 26 (1) ◽  
pp. 162-188 ◽  
Author(s):  
Ying Sun ◽  
George Z Voyiadjis ◽  
Weiping Hu ◽  
Fei Shen ◽  
Qingchun Meng
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Mechanics ◽  
Failure Modes ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Fretting Fatigue ◽  
Bolted Joints ◽  
Continuum Damage ◽  
Bolted Joint

Fatigue and fretting fatigue are the main failure mode in bolted joints when subjected to cyclic load. Based on continuum damage mechanics, an elastic–plastic fatigue damage model and a fretting fatigue damage model are combined to evaluate the fatigue property of bolted joints to cover the two different failure modes arisen at two possible critical sites. The predicted fatigue lives agree well with the experimental results available in the literature. The beneficial effects of clamping force on fatigue life improvement of the bolted joint are revealed: part of the load is transmitted by friction force in the contact interface, and the stress amplitude at the critical position is decreased due to the reduction in the force transmitted by the bolt. The negative effect of fretting damage on the bolted joint is also captured in the simulation.

Prediction of Fracture Resistance Behaviour Using Nonlocal Damage Model

2007 ◽  
Author(s):  
M. K. Samal ◽  
M. Seidenfuss ◽  
E. Roos ◽  
B. K. Dutta ◽  
H. S. Kushwaha
Keyword(s):  
Crack Initiation ◽  
Fracture Resistance ◽  
Damage Mechanics ◽  
Damage Model ◽  
Mesh Size ◽  
Continuum Damage Mechanics ◽  
Nonlocal Model ◽  
Continuum Damage ◽  
Local Damage ◽  
Spatial Discretisation

Prevention of failure of pressurised and high-energy components and systems has been an important issue in design of all types of power and process plants. Each individual component of these systems must be dimensioned such that it can resist the forces or moments to which it will be subjected during normal service and upset conditions. Design by analysis is an important philosophy of modern design. The ability of now-a-days computers to numerically handle complex mathematical problems has inspired the use highly nonlinear material behaviour (including material softening) instead of classical linear constitutive theory for the materials. Under the influence of these developments, a fundamentally different type of modelling has emerged, in which fracture is considered as the ultimate consequence of a material degradation process. Crack initiation and growth then follow naturally from the standard continuum mechanics theory (called continuum damage mechanics). Numerical analyses based on these so-called local damage models, however, are often found to depend on the spatial discretisation (i.e., mesh size of the numerical method used). The growth of damage tends to localise in the smallest band that can be captured by the spatial discretisation. As a consequence, increasingly finer discretisation grids can lead to crack initiation earlier in the loading history and to faster crack growth. This non-physical behaviour is caused by the fact that the localisation of damage in a vanishing volume is no longer consistent with the concept of a continuous damage field, which forms the basis of the continuum damage mechanics approach. In this work, the Rousellier’s damage model has been extended to its nonlocal form using damage parameter ‘d’ as a degree of freedom. The finite element (FE) equations have been derived using the weak form of the governing equations for both mechanical force equilibrium and the damage equilibrium. As an example, a standard fracture mechanics specimen [SE(B)] made up of a German low alloy steel has been analysed in 2D plane strain condition using different mesh sizes near the crack tip. The results of the nonlocal model has been compared with experimental results as well as with those predicted by the local model. It was observed that the fracture resistance predicted by the local damage model goes on decreasing when the mesh size near the crack tip is refined whereas the nonlocal model predicts a converged fracture resistance behaviour which compares well with the experimentally determined behaviour.

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