scholarly journals Comparison of Ductile Damage Models During Scratch Tests - A Numerical Study

2015 ◽  
Author(s):  
A. Mostaani ◽  
M.P. Pereira ◽  
B.F. Rolfe
Keyword(s):  
Material Removal ◽  
Numerical Study ◽  
Damage Model ◽  
Scratch Test ◽  
Work Piece ◽  
Damage Initiation ◽  
Damage Models ◽  
Wear Mode ◽  
Scratch Tests ◽  
Wear Modes

The ‘wear mode diagram’ has been commonly used to classify the deformation regime of the soft work-piece during scratching, into three modes: ploughing, wedge formation and cutting. The scratch test is used to evaluate wear modes and material removal associated with wear. There are different damage models in the literature used for the description of material behaviour after damage initiation under different loading conditions. However, there has been little analysis to compare damage models during scratch test conditions. The first aim of this work is first to use a finite element modelling package (Abaqus/Explicit) to build a 3D model to capture deformation modes during scratching with indenters with different attack angles. Three different damage models are incorporated into the model and patterns of damage initiation and propagation are compared with experimental results from the literature. This work highlights the role of the damage model in accurately capturing wear modes and material removal during two body sliding interactions.

Experimental and Three-Dimensional Finite Element Study of Scratch Test of Polymers at Large Deformations

2004 ◽  
Vol 126 (2) ◽  
pp. 372-379 ◽  
Author(s):  
J. L. Bucaille ◽  
E. Felder ◽  
G. Hochstetter
Keyword(s):  
Strain Hardening ◽  
Penetration Depth ◽  
Large Deformations ◽  
Numerical Study ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Plastic Strains ◽  
Thermosetting Polymer ◽  
Scratch Tests ◽  
Hardening Coefficient

An experimental and numerical study of the scratch test on polymers near their surface is presented. The elastoplastic response of three polymers is compared during scratch tests at large deformations: polycarbonate, a thermosetting polymer and a sol-gel hard coating composed of a hybrid matrix (thermosetting polymer-mineral) reinforced with oxide nanoparticles. The experiments were performed using a nanoindenter with a conical diamond tip having an included angle of 30 deg and a spherical radius of 600 nm. The observations obtained revealed that thermosetting polymers have a larger elastic recovery and a higher hardness than polycarbonate. The origin of this difference in scratch resistance was investigated with numerical modelling of the scratch test in three dimensions. Starting from results obtained by Bucaille (J. Mat. Sci., 37, pp. 3999–4011, 2002) using an inverse analysis of the indentation test, the mechanical behavior of polymers is modeled with Young’s modulus for the elastic part and with the G’sell-Jonas’ law with an exponential strain hardening for the viscoplastic part. The strain hardening coefficient is the main characteristic parameter differentiating the three studied polymers. Its value is equal to 0.5, 4.5, and 35, for polycarbonate, the thermosetting polymer and the reinforced thermosetting polymer, respectively. Firstly, simulations reveals that plastic strains are higher in scratch tests than in indentation tests, and that the magnitude of the plastic strains decreases as the strain hardening increases. For scratching on polycarbonate and for a penetration depth of 0.5 μm of the indenter mentioned above, the representative strain is equal to 124%. Secondly, in agreement with experimental results, numerical modeling shows that an increase in the strain hardening coefficient reduces the penetration depth of the indenter into the material and decreases the depth of the residual groove, which means an improvement in the scratch resistance.

A Damage Model for Adhesively Bonded Single-Lap Thick Composite Joints

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Sayed A. Nassar ◽  
Jianghui Mao ◽  
Xianjie Yang ◽  
Douglas Templeton
Keyword(s):  
Damage Mechanics ◽  
Resin Composite ◽  
Analytical Data ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Epoxy Adhesive ◽  
Failure Behavior ◽  
Adhesively Bonded ◽  
Damage Initiation ◽  
Damage Models

A proposed damage model is used for investigating the deformation and interfacial failure behavior of an adhesively bonded single-lap thick joint made of S2 glass/SC-15 epoxy resin composite material. The bonding material is 3M Scotch-Weld Epoxy Adhesive DP405 Black. Continuum damage mechanics models are used to describe the damage initiation and final failure at or near the interface. The effect of adhesive overlap length, thickness, and plasticity on the interfacial shear and normal stresses is studied. Experimental and analytical data are used to validate the proposed damage models.

scholarly journals Dynamic recrystallization-dependent damage modeling during hot forming

2019 ◽  
Vol 29 (2) ◽  
pp. 335-363 ◽  
Author(s):  
Muhammad Imran ◽  
Joanna Szyndler ◽  
Muhammad Junaid Afzal ◽  
Markus Bambach
Keyword(s):  
Dynamic Recrystallization ◽  
Elevated Temperatures ◽  
Damage Model ◽  
Hot Forming ◽  
Damage Initiation ◽  
Damage Models ◽  
Process Simulations ◽  
The Matrix ◽  
Different Temperatures ◽  
Stress States

Hot forming processes are extensively used to produce semi-finished and finished components. At elevated temperatures, dynamic recovery and recrystallization processes occur that enable large shape changes at low forming forces. In steel, non-metallic inclusions cannot be avoided during metallurgical processes. They may induce damage in the same way as at room temperature, but the softening of the matrix due to dynamic recrystallization may be used to control the initiation and progression of damage. Damage models do not take into account that dynamic recrystallization reduces the local stresses at the interface of matrix–inclusion. The purpose of the presented study is to analyze the interaction between dynamic recrystallization and damage initiation. Using representative volume elements, the influence of dynamic recrystallization on damage initiation is studied at different temperatures, strain rates, and stress states. Based on this study, a damage model is devised that couples dynamic recrystallization and damage on the macro level and hence can be used in macroscopic process simulations.

scholarly journals Viscoplastic Regularization of Local Damage Models: A Latent Solution

2012 ◽  
Vol 504-506 ◽  
pp. 845-850 ◽  
Author(s):  
M.S. Niazi ◽  
H.H. Wisselink ◽  
V. Timo Meinders
Keyword(s):  
Deformation Rate ◽  
Numerical Study ◽  
Physical Phenomenon ◽  
Damage Model ◽  
Mesh Size ◽  
Shear Loading ◽  
Local Damage ◽  
Damage Models ◽  
Rate Effects ◽  
Non Local

Local damage models are known to produce pathological mesh dependence in finite element simulations. The solution is to either use a regularization technique or to adopt a non-local damage model. Viscoplasticity is one technique which can regularize the mesh dependence of local damage model by incorporating a physical phenomenon in the constitutive model i.e. rate effects. A detailed numerical study of viscoplastic regularization is carried out in this work. Two case studies were considered i.e. a bar with shear loading and a sheet metal under tensile loading. The influence of hardening / softening parameters, prescribed deformation rate and mesh size on the regularization was studied. It was found that the primary viscoplastic length scale is a function of hardening and softening parameters but does not depend upon the deformation rate. Mesh dependency appeared at higher damage values. This mesh dependence can be reduced by mesh refinement in the localized region and also by increasing the deformation rates. The viscoplastic regularization was successfully used with a local anisotropic damage model to predict failure in a cross die drawing process with the actual physical process parameters.

Validation of the ductile fracture modeling of CGI at quasi-static loading conditions

2021 ◽  
pp. 105678952199754
Author(s):  
Senad Razanica ◽  
Lennart B Josefson ◽  
Ragnar Larsson ◽  
Torsten Sjögren
Keyword(s):  
Ductile Fracture ◽  
Damage Mechanics ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Image Correlation ◽  
Damage Initiation ◽  
Damage Models ◽  
Fracture Modeling ◽  
Static Conditions ◽  
Force Displacement

Fracture modeling and experimental validation of Compacted Graphite Iron (CGI) specimens loaded under quasi-static conditions at room temperature are considered. Continuum damage mechanics coupled to plasticity is adopted to describe the evolution of damage. The damage production is based on a recently developed rate dependent damage evolution law, where the damage–plasticity coupling is modeled based on a damage driving energy that involves both stored energy and plasticity contributions. To describe ductile fracture accounting for stress triaxiality on the damage initiation, the inelastic contribution to the damage driving energy is controlled by the Johnson-Cook failure criterion. Three different damage models are defined based on elastic/inelastic damage driving energies. The damage models are validated against experiments on a set of notched specimens made of CGI with different notch geometries, where the global force-displacement curves and corresponding strain fields are obtained using digital image correlation technology. It is shown from the testing and the simulations that plastic strains generally need to be accounted for in order to properly describe the different failure processes of the CGI specimens. In addition, the ductile damage model is shown to more accurately predict the experimental force-displacement response as compared to the more simplistic stress drop, element deletion technique.

scholarly journals Development of Elastoplastic-Damage Model of AlFeSi Phase for Aluminum Alloy 6061

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 954
Author(s):  
Hailong Wang ◽  
Wenping Deng ◽  
Tao Zhang ◽  
Jianhua Yao ◽  
Sujuan Wang
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Material Properties ◽  
Damage Model ◽  
Scratch Test ◽  
Aluminum Alloy 6061 ◽  
Ultra Precision ◽  
Simulation Results ◽  
Alloy 6061 ◽  
Elastoplastic Damage

Material properties affect the surface finishing in ultra-precision diamond cutting (UPDC), especially for aluminum alloy 6061 (Al6061) in which the cutting-induced temperature rise generates different types of precipitates on the machined surface. The precipitates generation not only changes the material properties but also induces imperfections on the generated surface, therefore increasing surface roughness for Al6061 in UPDC. To investigate precipitate effect so as to make a more precise control for the surface quality of the diamond turned Al6061, it is necessary to confirm the compositions and material properties of the precipitates. Previous studies have indicated that the major precipitate that induces scratch marks on the diamond turned Al6061 is an AlFeSi phase with the composition of Al86.1Fe8.3Si5.6. Therefore, in this paper, to study the material properties of the AlFeSi phase and its influences on ultra-precision machining of Al6061, an elastoplastic-damage model is proposed to build an elastoplastic constitutive model and a damage failure constitutive model of Al86.1Fe8.3Si5.6. By integrating finite element (FE) simulation and JMatPro, an efficient method is proposed to confirm the physical and thermophysical properties, temperature-phase transition characteristics, as well as the stress–strain curves of Al86.1Fe8.3Si5.6. Based on the developed elastoplastic-damage parameters of Al86.1Fe8.3Si5.6, FE simulations of the scratch test for Al86.1Fe8.3Si5.6 are conducted to verify the developed elastoplastic-damage model. Al86.1Fe8.3Si5.6 is prepared and scratch test experiments are carried out to compare with the simulation results, which indicated that, the simulation results agree well with those from scratch tests and the deviation of the scratch force in X-axis direction is less than 6.5%.

Numerical Investigation of Ductile Fracture in Pipelines Under Complex Loading Using a Phenomenological Damage Model

2021 ◽  
Author(s):  
Iago S. Santos ◽  
Diego F. B. Sarzosa
Keyword(s):  
Ductile Fracture ◽  
Mechanical Response ◽  
Numerical Study ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Numerical Procedure ◽  
Complex Loading ◽  
Experimental Tests ◽  
Compact Tension ◽  
Axial Tensile

Abstract This paper presents a numerical study on pipes ductile fracture mechanical response using a phenomenological computational damage model. The damage is controlled by an initiation criterion dependent on the stress triaxiality and the Lode angle parameter, and a post-initiation damage law to eliminate each finite element from the mesh. Experimental tests were carried out to calibrate the elastoplastic response, damage parameters and validate the FEM models. The tested geometries were round bars having smooth and notched cross-section, flat notched specimens under axial tensile loads, and fracture toughness tests in deeply cracked bending specimens SE(B) and compact tension samples C(T). The calibrated numerical procedure was applied to execute a parametric study in pipes with circumferential surface cracks subjected to tensile and internal pressure loads simultaneously. The effects of the variation of geometric parameters and the load applications on the pipes strain capacity were investigated. The influence of longitudinal misalignment between adjacent pipes was also investigated.

Study of material removal mechanisms in grinding of C/SiC composites via single-abrasive scratch tests

2019 ◽  
Vol 45 (4) ◽  
pp. 4729-4738 ◽  
Author(s):  
Yuanchen Li ◽  
Xiang Ge ◽  
Hui Wang ◽  
Yingbin Hu ◽  
Fuda Ning ◽  
...  
Keyword(s):  
Material Removal ◽  
Material Removal Mechanisms ◽  
Removal Mechanisms ◽  
Sic Composites ◽  
Scratch Tests

scholarly journals A 3D multi-scratch test model for characterizing material removal regimes in 5083-Al alloy

2015 ◽  
Vol 87 ◽  
pp. 352-362 ◽  
Author(s):  
F. Elwasli ◽  
F. Zemzemi ◽  
A. Mkaddem ◽  
S. Mzali ◽  
S. Mezlini
Keyword(s):  
Material Removal ◽  
Scratch Test ◽  
Al Alloy ◽  
Test Model ◽  
5083 Al Alloy

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.

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