X. Decoopman | Université des Sciences et Technologies de Lille (Lille-1) (original) (raw)
Papers by X. Decoopman
Fatigue damage accumulation of cold expanded hole in aluminum alloys used in land transportation ... more Fatigue damage accumulation of cold expanded hole in aluminum alloys used in land transportation components was investigated. Tests were carried out using pre-cracked SENT specimens and inserting an expanded hole at the crack tip. The degree of the cold expansion was chosen equal to 4.3%. Tests were performed in two and four block loading under constant amplitude. Two sequences were
International Journal of Fatigue, 2007
Many engineering structures are subjected to random loading. The problem of predicting crack grow... more Many engineering structures are subjected to random loading. The problem of predicting crack growth rates in this case cannot be solved without an accurate knowledge of load-time history occurring in service. There are many calculating models of crack propagation under spectrum loading, such as Wheeler model [Wheeler O. Spectrum loading and crack growth. J Basic Eng D 1972;94:181–86], Huang et
Surface Engineering, 2007
The work presented in the present paper aims at evaluating the opportunity of the eddy current me... more The work presented in the present paper aims at evaluating the opportunity of the eddy current method to characterise the decarburising extent which can occur during usual heat treatments of steel like austenising. The present work is based on previous studies highlighting the ability of eddy current to detect superficial defects such as cracks, pores or the possibility to corroborate its signal intensity with the mechanical microhardness modifications generated by carburising of steel. That is why eddy current is used here to systematically compare non-affected sample with the decarburised ones at different levels of decarburising. Among the techniques available to characterise the extent of decarburising, i.e. optical observations and microhardness profile, the eddy current technique provides a non-destructive method which is often required from an industrial control point of view. The results obtained show a strong correlation between the eddy current signal and the decarburised depth of the samples. As a consequence, they open realistic perspectives to characterise decarburising industrially.
International Journal of Mechanical Sciences, 2013
ABSTRACT The determination of the tensile properties by spherical indentation is based on the rel... more ABSTRACT The determination of the tensile properties by spherical indentation is based on the relation of Tabor, which links the mean pressure and the indent diameter, obtained from indentation tests, to the stress and strain determined from a tensile test, respectively. However, in order to improve the indentation– tensile relationship, an additional correction related to the piling-up or sinking-in formation around the indent must be taken into account for the calculation of the strain by indentation. The correction factor is expressed as a function of the strain-hardening exponent. As a consequence, to validate such methodology, majority of the authors use the strain-hardening exponent previously determined by a tensile test. Unfortunately, this approach obviously impedes a direct construction of the tensile curve from indentation tests since the strain-hardening exponent will be undetermined. In addition, the tensile stress to mean pressure ratio is not a constant value because it depends on the mechanical properties and on the deformation regime. To circumvent these two problems, a simple expression of the mean pressure to stress ratio is proposed in macroindentation as a function of the strain-hardening exponent, which is determined by indentation tests using the relations of Hollomon and Ramberg–Osgood. This methodol-ogy, which allows the construction of the stress –strain curve only from indentation tests, is validated on a low-carbon steel and a commercial brass.
Your article is protected by copyright and all rights are held exclusively by ASM International. ... more Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Thin Solid Films, 2011
In order to characterize the adhesion of nanostructured plasma-sprayed Y2O3–ZrO2 coatings present... more In order to characterize the adhesion of nanostructured plasma-sprayed Y2O3–ZrO2 coatings presenting some geometrical specificities, it is here suggested to apply the Vickers Indentation Cracking (VIC) technique, which is capable of initiating a crack at the interface by performing the indentation test close to the interface within the substrate. This method renders it possible to overcome the difficulties concerning the
Materials Science and Engineering: A, 2008
In different engineering applications such as automobile and train crashes, the high speed impact... more In different engineering applications such as automobile and train crashes, the high speed impact of debris as well as the high speed manufacturing processes, makes it necessary to have a deep understanding of the dynamic behavior of materials and components. There are different experimental techniques to determine the constitutive material behavior. Several constitutive models have been proposed to predict the dynamic response of engineering structures. However, in all cases, initial damage-free material is assumed and the structures are without fatigue damage when tested. The dynamic response of fatigue damaged steel and aluminum specimens subjected to impact loading are investigated in this work. Samples subjected to previous high cycle fatigue are considered. Results show that previous fatigue damage affects the quasi-static behavior of steel more significantly than that of aluminum. Dynamic yield stress of 6061-T6 aluminum samples shows it to be more sensitive to fatigue damage than to strain rate. Previous fatigue damage has a detrimental effect on ductility of 4140T steel, principally under dynamic loading.
Materials Science and Engineering: A, 2011
A methodology for obtaining a nanocrystalline Al 91 -Mn 6 -Nd 3 alloy and characterizing its mech... more A methodology for obtaining a nanocrystalline Al 91 -Mn 6 -Nd 3 alloy and characterizing its mechanical properties is presented. The fabrication procedure, based on the melt spinning method, allowed the preparation of thin ribbons of ∼30 m in thickness. The hardness and elastic modulus have been determined by classical and instrumented indentation tests considering the influence of the ribbon thickness on the indentation measurements. The Martens hardness has been calculated by means of instrumented indentation tests, for which the fixing support of the sample has no influence on the indentation measurement. The results have been subsequently compared with those obtained from classical Vickers hardness measurements, for which some composite hardness models have been applied in order to separate the contribution of the fixing support to the hardness measurement. It has been concluded that both methodologies lead to similar values for the mechanical properties of the alloy, i.e. ∼3.4 GPa for the macrohardness and ∼3.8 MPa m 1/2 for the hardness length-scale factor of the material. The elastic modulus of the material, resulting from the analysis of the unloading indentation curves, has been found to be ∼131 GPa.
Materials Science and Engineering: A, 2013
The recent development of the instrumented indentation technique allows the determination of the ... more The recent development of the instrumented indentation technique allows the determination of the mechanical properties of materials by analyzing the load-depth curve. In hard materials a "sinking-in" type deformation is observed during indentation and the contact area for such materials is usually calculated using the methodology proposed by Oliver and Pharr [1]. However, in softer materials, "piling-up" instead of "sinking-in" occurs along the edges of the residual indent and, in this case, the methodology proposed by Hochstetter et al. is appropriate.
Journal of the Mechanical Behavior of Biomedical Materials, 2013
Elastic modulus Martens hardness Creep Instrumented indentation test a b s t r a c t Properties o... more Elastic modulus Martens hardness Creep Instrumented indentation test a b s t r a c t Properties of elasticity, hardness and viscosity are determined for the study of the viscoelastoplastic behavior of bones. The mechanical properties are compared in two upright sections of the bone due to their anisotropy. Besides, influence of hydration treatments leading to structural modifications of collagen and ground substance contents of bones on the mechanical properties is studied on a femoral cortical bovine bone. The treatments applied to the bone are used by forensic anthropologists to remove the soft tissue and modifying the hydration degree coupled to the collagen content. From instrumented indentation experiments, the hardness is characterized by the macrohardness and a hardness length-scale factor stating the hardness-load dependence. The elastic modulus results from the application of the methodology of Oliver and Pharr (1992). The coefficient of viscosity is deduced from a rheological model representing the indenter time-displacement observed under the application of a constant load. As a result, all the mechanical properties are found to be lower in the transverse section in an extent
International Journal of Fatigue, 2008
It is often necessary to predict the response of engineering structures when subjected to impact ... more It is often necessary to predict the response of engineering structures when subjected to impact loading conditions such as: automobile and train crash, high speed impact of debris and high speed manufacturing processes. An optimum combination of body structure and material is highly required and thus an exact evaluation of high strain rate properties of materials has been demanded. However
International Journal of Fatigue, 2007
... b Mechanical Faculty of Timisoara, Bd. Mihai Viteazu Nr.1, Timisoara 300222, Romania. c The “... more ... b Mechanical Faculty of Timisoara, Bd. Mihai Viteazu Nr.1, Timisoara 300222, Romania. c The “Stefan cel mare” University of Suceava, Universitatii 13, 720229 Suceava, Romania. Received 7 September 2006; revised 16 February 2007; accepted 26 February 2007. ...
International Journal of Microstructure and Materials Properties, 2013
Reference to this paper should be made as follows: Decoopman, X., Nosei, L., Lesage, J., Chicot, ... more Reference to this paper should be made as follows: Decoopman, X., Nosei, L., Lesage, J., Chicot, D. and Feugeas, J. (2013) 'Role of plastic deformation on the efficiency of a nitriding treatment: modelling of the hardness-depth profile ', Int. J. Microstructure and Materials Properties, Vol. 8, No. 3, Biographical notes: Xavier Decoopman received his PhD from the University Lille1, Sciences and Technology. He has published 12 publications and is co-author in five proceedings of congress. He worked on the fatigue crack propagation and on multiaxial fatigue. Since 2010, his research area consists on the determination of mechanical properties of massive and coated materials by means of the instrumented indentation tests. Hardness, elastic modulus, toughness, adhesion of coatings and tensile properties by indentation are analysed using indentation testing conditions from nano to macroindentation. He participates to several international projects supported
Fatigue damage accumulation of cold expanded hole in aluminum alloys used in land transportation ... more Fatigue damage accumulation of cold expanded hole in aluminum alloys used in land transportation components was investigated. Tests were carried out using pre-cracked SENT specimens and inserting an expanded hole at the crack tip. The degree of the cold expansion was chosen equal to 4.3%. Tests were performed in two and four block loading under constant amplitude. Two sequences were
International Journal of Fatigue, 2007
Many engineering structures are subjected to random loading. The problem of predicting crack grow... more Many engineering structures are subjected to random loading. The problem of predicting crack growth rates in this case cannot be solved without an accurate knowledge of load-time history occurring in service. There are many calculating models of crack propagation under spectrum loading, such as Wheeler model [Wheeler O. Spectrum loading and crack growth. J Basic Eng D 1972;94:181–86], Huang et
Surface Engineering, 2007
The work presented in the present paper aims at evaluating the opportunity of the eddy current me... more The work presented in the present paper aims at evaluating the opportunity of the eddy current method to characterise the decarburising extent which can occur during usual heat treatments of steel like austenising. The present work is based on previous studies highlighting the ability of eddy current to detect superficial defects such as cracks, pores or the possibility to corroborate its signal intensity with the mechanical microhardness modifications generated by carburising of steel. That is why eddy current is used here to systematically compare non-affected sample with the decarburised ones at different levels of decarburising. Among the techniques available to characterise the extent of decarburising, i.e. optical observations and microhardness profile, the eddy current technique provides a non-destructive method which is often required from an industrial control point of view. The results obtained show a strong correlation between the eddy current signal and the decarburised depth of the samples. As a consequence, they open realistic perspectives to characterise decarburising industrially.
International Journal of Mechanical Sciences, 2013
ABSTRACT The determination of the tensile properties by spherical indentation is based on the rel... more ABSTRACT The determination of the tensile properties by spherical indentation is based on the relation of Tabor, which links the mean pressure and the indent diameter, obtained from indentation tests, to the stress and strain determined from a tensile test, respectively. However, in order to improve the indentation– tensile relationship, an additional correction related to the piling-up or sinking-in formation around the indent must be taken into account for the calculation of the strain by indentation. The correction factor is expressed as a function of the strain-hardening exponent. As a consequence, to validate such methodology, majority of the authors use the strain-hardening exponent previously determined by a tensile test. Unfortunately, this approach obviously impedes a direct construction of the tensile curve from indentation tests since the strain-hardening exponent will be undetermined. In addition, the tensile stress to mean pressure ratio is not a constant value because it depends on the mechanical properties and on the deformation regime. To circumvent these two problems, a simple expression of the mean pressure to stress ratio is proposed in macroindentation as a function of the strain-hardening exponent, which is determined by indentation tests using the relations of Hollomon and Ramberg–Osgood. This methodol-ogy, which allows the construction of the stress –strain curve only from indentation tests, is validated on a low-carbon steel and a commercial brass.
Your article is protected by copyright and all rights are held exclusively by ASM International. ... more Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Thin Solid Films, 2011
In order to characterize the adhesion of nanostructured plasma-sprayed Y2O3–ZrO2 coatings present... more In order to characterize the adhesion of nanostructured plasma-sprayed Y2O3–ZrO2 coatings presenting some geometrical specificities, it is here suggested to apply the Vickers Indentation Cracking (VIC) technique, which is capable of initiating a crack at the interface by performing the indentation test close to the interface within the substrate. This method renders it possible to overcome the difficulties concerning the
Materials Science and Engineering: A, 2008
In different engineering applications such as automobile and train crashes, the high speed impact... more In different engineering applications such as automobile and train crashes, the high speed impact of debris as well as the high speed manufacturing processes, makes it necessary to have a deep understanding of the dynamic behavior of materials and components. There are different experimental techniques to determine the constitutive material behavior. Several constitutive models have been proposed to predict the dynamic response of engineering structures. However, in all cases, initial damage-free material is assumed and the structures are without fatigue damage when tested. The dynamic response of fatigue damaged steel and aluminum specimens subjected to impact loading are investigated in this work. Samples subjected to previous high cycle fatigue are considered. Results show that previous fatigue damage affects the quasi-static behavior of steel more significantly than that of aluminum. Dynamic yield stress of 6061-T6 aluminum samples shows it to be more sensitive to fatigue damage than to strain rate. Previous fatigue damage has a detrimental effect on ductility of 4140T steel, principally under dynamic loading.
Materials Science and Engineering: A, 2011
A methodology for obtaining a nanocrystalline Al 91 -Mn 6 -Nd 3 alloy and characterizing its mech... more A methodology for obtaining a nanocrystalline Al 91 -Mn 6 -Nd 3 alloy and characterizing its mechanical properties is presented. The fabrication procedure, based on the melt spinning method, allowed the preparation of thin ribbons of ∼30 m in thickness. The hardness and elastic modulus have been determined by classical and instrumented indentation tests considering the influence of the ribbon thickness on the indentation measurements. The Martens hardness has been calculated by means of instrumented indentation tests, for which the fixing support of the sample has no influence on the indentation measurement. The results have been subsequently compared with those obtained from classical Vickers hardness measurements, for which some composite hardness models have been applied in order to separate the contribution of the fixing support to the hardness measurement. It has been concluded that both methodologies lead to similar values for the mechanical properties of the alloy, i.e. ∼3.4 GPa for the macrohardness and ∼3.8 MPa m 1/2 for the hardness length-scale factor of the material. The elastic modulus of the material, resulting from the analysis of the unloading indentation curves, has been found to be ∼131 GPa.
Materials Science and Engineering: A, 2013
The recent development of the instrumented indentation technique allows the determination of the ... more The recent development of the instrumented indentation technique allows the determination of the mechanical properties of materials by analyzing the load-depth curve. In hard materials a "sinking-in" type deformation is observed during indentation and the contact area for such materials is usually calculated using the methodology proposed by Oliver and Pharr [1]. However, in softer materials, "piling-up" instead of "sinking-in" occurs along the edges of the residual indent and, in this case, the methodology proposed by Hochstetter et al. is appropriate.
Journal of the Mechanical Behavior of Biomedical Materials, 2013
Elastic modulus Martens hardness Creep Instrumented indentation test a b s t r a c t Properties o... more Elastic modulus Martens hardness Creep Instrumented indentation test a b s t r a c t Properties of elasticity, hardness and viscosity are determined for the study of the viscoelastoplastic behavior of bones. The mechanical properties are compared in two upright sections of the bone due to their anisotropy. Besides, influence of hydration treatments leading to structural modifications of collagen and ground substance contents of bones on the mechanical properties is studied on a femoral cortical bovine bone. The treatments applied to the bone are used by forensic anthropologists to remove the soft tissue and modifying the hydration degree coupled to the collagen content. From instrumented indentation experiments, the hardness is characterized by the macrohardness and a hardness length-scale factor stating the hardness-load dependence. The elastic modulus results from the application of the methodology of Oliver and Pharr (1992). The coefficient of viscosity is deduced from a rheological model representing the indenter time-displacement observed under the application of a constant load. As a result, all the mechanical properties are found to be lower in the transverse section in an extent
International Journal of Fatigue, 2008
It is often necessary to predict the response of engineering structures when subjected to impact ... more It is often necessary to predict the response of engineering structures when subjected to impact loading conditions such as: automobile and train crash, high speed impact of debris and high speed manufacturing processes. An optimum combination of body structure and material is highly required and thus an exact evaluation of high strain rate properties of materials has been demanded. However
International Journal of Fatigue, 2007
... b Mechanical Faculty of Timisoara, Bd. Mihai Viteazu Nr.1, Timisoara 300222, Romania. c The “... more ... b Mechanical Faculty of Timisoara, Bd. Mihai Viteazu Nr.1, Timisoara 300222, Romania. c The “Stefan cel mare” University of Suceava, Universitatii 13, 720229 Suceava, Romania. Received 7 September 2006; revised 16 February 2007; accepted 26 February 2007. ...
International Journal of Microstructure and Materials Properties, 2013
Reference to this paper should be made as follows: Decoopman, X., Nosei, L., Lesage, J., Chicot, ... more Reference to this paper should be made as follows: Decoopman, X., Nosei, L., Lesage, J., Chicot, D. and Feugeas, J. (2013) 'Role of plastic deformation on the efficiency of a nitriding treatment: modelling of the hardness-depth profile ', Int. J. Microstructure and Materials Properties, Vol. 8, No. 3, Biographical notes: Xavier Decoopman received his PhD from the University Lille1, Sciences and Technology. He has published 12 publications and is co-author in five proceedings of congress. He worked on the fatigue crack propagation and on multiaxial fatigue. Since 2010, his research area consists on the determination of mechanical properties of massive and coated materials by means of the instrumented indentation tests. Hardness, elastic modulus, toughness, adhesion of coatings and tensile properties by indentation are analysed using indentation testing conditions from nano to macroindentation. He participates to several international projects supported