Machining Simulation for Ceramics Based on Continuum Damage Mechanics

2002 ◽  
Vol 124 (3) ◽  
pp. 553-561 ◽  
Author(s):  
Xianbing Liu ◽  
Bi Zhang
Keyword(s):  
Silicon Nitride ◽  
Damage Mechanics ◽  
Current Model ◽  
Continuum Damage Mechanics ◽  
Machining Process ◽  
Depth Of Cut ◽  
Contour Plot ◽  
Continuum Damage ◽  
Damage State ◽  
Highly Nonlinear

An abrasive machining process for ceramics is simulated with a nonlinear thermodynamic constitutive model based on the principle of continuum damage mechanics (CDM). The model consists of a set of parallel Maxwell-type elements arranged in series with a spring. It incorporates stochastic material microstructure through two sets of the newly introduced material parameters, spring-like constants Cr and damping-like coefficients arr=1,2,…,n. Damage is considered cumulative and related with current stress and damage state in a ceramic workpiece during loading, which constitutes damage evolution. A fourth-order isotropic damage tensor is introduced. This highly nonlinear CDM model is reduced to an incremental formulation and approximated by a 3D nonlinear finite element program based on the Newton-Raphson method. The stress-strain correlation calculated from the current model is presented for alumina, silicon carbide, and silicon nitride. The predicted results of damage versus the depth of cut for the three ceramics subjected to machining with single diamond grit are validated by the experiment. As one example, the development of damage with the movement of the abrasive grit in a silicon nitride workpiece is demonstrated by a contour plot. The final part of this paper presents the calculated distribution of residual stress in a silicon nitride sample and the factors contributing to the distribution are discussed.

Damage Mechanisms Modeling for Ceramic Composites

1994 ◽  
Vol 116 (3) ◽  
pp. 331-336 ◽  
Author(s):  
P. Ladeve`ze ◽  
A. Gasser ◽  
O. Allix
Keyword(s):  
Structural Analysis ◽  
Damage Mechanics ◽  
Constitutive Relations ◽  
Continuum Damage Mechanics ◽  
Ceramic Composites ◽  
Continuum Damage ◽  
Damage State ◽  
Damage Mechanisms ◽  
Final Fracture

For ceramic composites, continuum damage mechanics models are built, which include information coming from both the “micro” and “macro” scales. These models are constitutive relations which, when included in a structural analysis code, are able to predict the damage state of the studied structure at any time and at any point until final fracture.

Notion of Continuum Damage Mechanics and its Application to Anisotropic Creep Damage Theory

1983 ◽  
Vol 105 (2) ◽  
pp. 99-105 ◽  
Author(s):  
S. Murakami
Keyword(s):  
Damage Mechanics ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Damage State ◽  
Creep Theory ◽  
Damage Theory ◽  
Damaged Materials ◽  
Damage Tensor ◽  
Anisotropic Creep

After discussing the notion and the practical procedures of continuum damage mechanics, their utility is elucidated by applying them to formulate an anisotropic creep damage theory for nonsteady multiaxial states of stress. By taking account of the mechanisms of microstructural change of materials due to creep, it is shown that the creep damage state can be described by a second rank symmetric damage tensor, while the effects of material damage on creep deformation of damaged materials should be expressed by a fourth rank tensor formed from the damage tensor. Validity of the creep theory formulated in terms of these damage variables is examined by performing model tests. Specialization of the proposed theory is also discussed.

scholarly journals DESCRIPTION OF DETERIORATION PROCESSES: DAMAGE PARAMETER OF Y.N. RABOTNOV: HISTORICAL REMARKS, FUNDAMENTAL RESULTS AND CONTEMPORARY STATE

2017 ◽  
Vol 20 (3) ◽  
pp. 97-114 ◽  
Author(s):  
L.V. Stepanova ◽  
S.A. Igonin
Keyword(s):  
Damage Accumulation ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Damage Parameter ◽  
Continuum Damage ◽  
Damage State ◽  
Detailed Review ◽  
Contemporary State ◽  
Historical Remarks

In the paper the detailed review of the present-day results related to problems of continuum damage mechanics is given. The survey shows the development of ideas of Y.N. Rabotnov who together with L.M. Kachanov introduced damage and continuity variables which characterize the damage state. In the paper the recent studies in the elasticity, plasticity and creep theories accounting for damage accumulation processes are discussed.

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.

Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

2021 ◽  
pp. 146442072110134
Author(s):  
A Nayebi ◽  
H Rokhgireh ◽  
M Araghi ◽  
M Mohammadi
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Element Model ◽  
Continuum Damage ◽  
Compression Tests ◽  
Compression Properties ◽  
Mechanics Model ◽  
Stress Components ◽  
Tension And Compression ◽  
Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

Creep Life Prediction of Aircraft Turbine Disc Alloy Using Continuum Damage Mechanics

2017 ◽  
Vol 38 (1) ◽  
pp. 25-30
Author(s):  
Yan-Feng Li ◽  
Zhisheng Zhang ◽  
Chenglin Zhang ◽  
Jie Zhou ◽  
Hong-Zhong Huang
Keyword(s):  
Numerical Analysis ◽  
Test Data ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Creep Model ◽  
Continuum Damage ◽  
Creep Life ◽  
Creep Life Prediction ◽  
Turbine Disc

Abstract This paper deals with the creep characteristics of the aircraft turbine disc material of nickel-base superalloy GH4169 under high temperature. From the perspective of continuum damage mechanics, a new creep life prediction model is proposed to predict the creep life of metallic materials under both uniaxial and multiaxial stress states. The creep test data of GH4169 under different loading conditions are used to demonstrate the proposed model. Moreover, from the perspective of numerical simulation, the test data with analysis results obtained by using the finite element analysis based on Graham creep model is carried out for comparison. The results show that numerical analysis results are in good agreement with experimental data. By incorporating the numerical analysis and continuum damage mechanics, it provides an effective way to accurately describe the creep damage process of GH4169.

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