https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 09 Jun 2026 18:59:15 GMT 2026-06-09T18:59:15Z http://hdl.handle.net/10985/25863 Exploring the effect of layer thickness on the elastoplastic properties of the constituent materials of CrN/CrAlN multilayer coatings: a nanoindentation and finite element-based investigation AMMAR, Yamen Ben; AOUADI, Khalil; BESNARD, Aurélien; MONTAGNE, Alex; NOUVEAU, Corinne; BOUCHOUCHA, Faker This paper aims to assess the effect of layer thickness on the elastoplastic properties of the constituent materials of multilayer coating systems, as well as on the stress and strain fields in the vicinity of the coating/substrate interface. A methodology based on a trust-region reflective optimization algorithm, integrated with finite element analysis of the nanoindentation process, is employed to extract the elastoplastic properties of the distinct layers, constituting multilayer coating. This approach is validated on a CrN/CrAlN multilayer coating systems with varying layer thicknesses from 1 to 0.35 µm, by which Young's modulus (E), yield stress (σy), and work hardening exponent (n) of each individual coating material layer were obtained. The results revealed a reduction in the hardness and Young's modulus of either CrN, or CrAlN coating layer as the layer thickness decreased. Finite element analysis of the nanoindentation process demonstrated that decreasing the coating layer thickness leads to an increase in the plastic deformation within the coatings, which reduces the stress concentration in this area. The simulation results suggest that an optimum thickness of 0.5 μm of CrAlN and CrN monolayer materials would improve the adhesion properties of CrN/CrAlN multilayer coatings. Fri, 15 Nov 2024 00:00:00 GMT http://hdl.handle.net/10985/25863 2024-11-15T00:00:00Z AMMAR, Yamen Ben AOUADI, Khalil BESNARD, Aurélien MONTAGNE, Alex NOUVEAU, Corinne BOUCHOUCHA, Faker This paper aims to assess the effect of layer thickness on the elastoplastic properties of the constituent materials of multilayer coating systems, as well as on the stress and strain fields in the vicinity of the coating/substrate interface. A methodology based on a trust-region reflective optimization algorithm, integrated with finite element analysis of the nanoindentation process, is employed to extract the elastoplastic properties of the distinct layers, constituting multilayer coating. This approach is validated on a CrN/CrAlN multilayer coating systems with varying layer thicknesses from 1 to 0.35 µm, by which Young's modulus (E), yield stress (σy), and work hardening exponent (n) of each individual coating material layer were obtained. The results revealed a reduction in the hardness and Young's modulus of either CrN, or CrAlN coating layer as the layer thickness decreased. Finite element analysis of the nanoindentation process demonstrated that decreasing the coating layer thickness leads to an increase in the plastic deformation within the coatings, which reduces the stress concentration in this area. The simulation results suggest that an optimum thickness of 0.5 μm of CrAlN and CrN monolayer materials would improve the adhesion properties of CrN/CrAlN multilayer coatings. http://hdl.handle.net/10985/25602 A Method to Extract the Elastoplastic Properties of the Constituent Layers of Multilayer Coatings BEN AMMAR, Yamen; AOUADI, Khalil; BOUCHOUCHA, Faker; NOUVEAU, Corinne; BESNARD, Aurélien; MONTAGNE, Alex This paper presents an approach to characterize the elastoplastic properties of the distinct layers, constituting multilayer coating. The proposed procedure utilizes nanoindentation load-displacement (P-h) curves and a non linear least squares fitting analysis to extract the elastoplastic properties of each layer in the multilayer coating. The accuracy of the optimization results is achieved by choosing initial guess parameters closer to the target values using the modified Jönsson and Hogmark model. The methodology is validated on a CrN/CrAlN multilayer coating systems with varying layer thicknesses from 1 to 0.5 μm, from which the optimal elastoplastic properties: Young’s modulus (E), yield stress (σy), and strain hardening exponent (n) of each individual layer were determined. The results show good agreement between the simulated and the experimental (P-h) curves. Furthermore, the results revealed a reduction in the material parameters (E, H and σY) of the constituent layers when the layer thickness decreases. These findings suggest that decreasing the coating layer thickness lead to an increase in the plastic deformation within the coatings, which reduces the stress concentration in this area and improves the adhesion properties of CrN/CrAlN multilayer coatings. Bourse d'alternance de 6 mois/an - Ministère tunisien Wed, 28 Aug 2024 00:00:00 GMT http://hdl.handle.net/10985/25602 2024-08-28T00:00:00Z BEN AMMAR, Yamen AOUADI, Khalil BOUCHOUCHA, Faker NOUVEAU, Corinne BESNARD, Aurélien MONTAGNE, Alex This paper presents an approach to characterize the elastoplastic properties of the distinct layers, constituting multilayer coating. The proposed procedure utilizes nanoindentation load-displacement (P-h) curves and a non linear least squares fitting analysis to extract the elastoplastic properties of each layer in the multilayer coating. The accuracy of the optimization results is achieved by choosing initial guess parameters closer to the target values using the modified Jönsson and Hogmark model. The methodology is validated on a CrN/CrAlN multilayer coating systems with varying layer thicknesses from 1 to 0.5 μm, from which the optimal elastoplastic properties: Young’s modulus (E), yield stress (σy), and strain hardening exponent (n) of each individual layer were determined. The results show good agreement between the simulated and the experimental (P-h) curves. Furthermore, the results revealed a reduction in the material parameters (E, H and σY) of the constituent layers when the layer thickness decreases. These findings suggest that decreasing the coating layer thickness lead to an increase in the plastic deformation within the coatings, which reduces the stress concentration in this area and improves the adhesion properties of CrN/CrAlN multilayer coatings. http://hdl.handle.net/10985/27106 Physico-Chemical and Mechanical Properties of DC-Sputtered ZrO2 Coatings Prepared by Oblique Angle Deposition GZAIEL, Asma; AOUADI, Khalil; BESNARD, Aurélien; NOUVEAU, Corinne; PINOT, Yoann; BOUCHOUCHA, Faker; BOUAOUINA, Boudjemaa In this study, a ZrO2 thin film was deposited onto a Ti6Al4V substrate using the Oblique Angle Deposition (OAD) technique. The influence of the substrate/Zr target an-gle (15°, 30°, 45°, and 60°) was investigated, with a fixed azimuthal orientation (Phi) of 180°. The primary objective of this work is to develop and characterize novel biocompatible coat-ings for hip prosthesis implants with a complex 3D spherical geometry. The OAD method enables thin film deposition on such geometries and enhances understanding of how the par-ticle incidence angle affects the surface morphology and microstructure of zirconium oxide (ZrO2) thin films. This study combines an experimental approach DC magnetron sputtering with a multi-scale numerical approach using Monte Carlo codes (SRIM, SIMTRA, and NASCAM). The structure, texture, and growth of the ZrO2 coatings were analyzed via X-ray diffraction (XRD), while microstructure and surface morphology were examined using scan-ning electron microscopy (SEM). Hardness and Young’s modulus were determined through nanoindentation testing. Results indicate that increasing the oblique angle leads to a decrease in hardness. Experimental and numerical findings complement each other, offering deeper insight into the deposition phenomena. SIMTRA simulations closely replicate experimental observations: a higher number of incident particles results in increased coating thickness. Additionally, the film thickness decreases with increasing substrate inclination angle. The microstructure of ZrO₂ thin films is strongly influenced by substrate orientation, and coated substrates demonstrate superior performance compared to their uncoated counterparts. Sat, 25 Oct 2025 00:00:00 GMT http://hdl.handle.net/10985/27106 2025-10-25T00:00:00Z GZAIEL, Asma AOUADI, Khalil BESNARD, Aurélien NOUVEAU, Corinne PINOT, Yoann BOUCHOUCHA, Faker BOUAOUINA, Boudjemaa In this study, a ZrO2 thin film was deposited onto a Ti6Al4V substrate using the Oblique Angle Deposition (OAD) technique. The influence of the substrate/Zr target an-gle (15°, 30°, 45°, and 60°) was investigated, with a fixed azimuthal orientation (Phi) of 180°. The primary objective of this work is to develop and characterize novel biocompatible coat-ings for hip prosthesis implants with a complex 3D spherical geometry. The OAD method enables thin film deposition on such geometries and enhances understanding of how the par-ticle incidence angle affects the surface morphology and microstructure of zirconium oxide (ZrO2) thin films. This study combines an experimental approach DC magnetron sputtering with a multi-scale numerical approach using Monte Carlo codes (SRIM, SIMTRA, and NASCAM). The structure, texture, and growth of the ZrO2 coatings were analyzed via X-ray diffraction (XRD), while microstructure and surface morphology were examined using scan-ning electron microscopy (SEM). Hardness and Young’s modulus were determined through nanoindentation testing. Results indicate that increasing the oblique angle leads to a decrease in hardness. Experimental and numerical findings complement each other, offering deeper insight into the deposition phenomena. SIMTRA simulations closely replicate experimental observations: a higher number of incident particles results in increased coating thickness. Additionally, the film thickness decreases with increasing substrate inclination angle. The microstructure of ZrO₂ thin films is strongly influenced by substrate orientation, and coated substrates demonstrate superior performance compared to their uncoated counterparts. http://hdl.handle.net/10985/26943 Wave propagation in laminated structure through wave finite element method ARFA, Henia; BOUCHOUCHA, Faker; DEBBICH, Hayet; AOUADI, Khalil; BEN AMMAR, Yamen; NOUVEAU, Corinne In this paper, the wave finite element(WFE) method is briefly presented and applied in order to extract the dispersion curves. The formulation of the laminated structure is detailed through the Timoshenko theory. The finite element technique is used to model the laminated beam and extract the mass and stiffness matrices for the bending vibration. The bending vibration of the laminated beam is simulated and discussed. The travelling and evanescent modes are illustrated to characterize the flexural wave propagation in laminated structure. The resolution of the equilibrium equation leads to the extraction of the analytical wave number as a function of the frequency in order to validate the dispersion curves simulated through the WFE method. The question of the influence of the layers thickness on the wave propagation is detailed. An uncertainty is introduced in the thickness as a Gaussian variable and the mean and the standard deviation of the dispersion curves are extracted through the Monte Carlo simulation. Among the contributions of this article, the laminated structures are modeled through the Abaqus software and the mass and stiffness matrices are extracted for the multimodal propagation. The multimodal wave number is presented and discussed for the travelling and evanescent modes. Thu, 03 Jul 2025 00:00:00 GMT http://hdl.handle.net/10985/26943 2025-07-03T00:00:00Z ARFA, Henia BOUCHOUCHA, Faker DEBBICH, Hayet AOUADI, Khalil BEN AMMAR, Yamen NOUVEAU, Corinne In this paper, the wave finite element(WFE) method is briefly presented and applied in order to extract the dispersion curves. The formulation of the laminated structure is detailed through the Timoshenko theory. The finite element technique is used to model the laminated beam and extract the mass and stiffness matrices for the bending vibration. The bending vibration of the laminated beam is simulated and discussed. The travelling and evanescent modes are illustrated to characterize the flexural wave propagation in laminated structure. The resolution of the equilibrium equation leads to the extraction of the analytical wave number as a function of the frequency in order to validate the dispersion curves simulated through the WFE method. The question of the influence of the layers thickness on the wave propagation is detailed. An uncertainty is introduced in the thickness as a Gaussian variable and the mean and the standard deviation of the dispersion curves are extracted through the Monte Carlo simulation. Among the contributions of this article, the laminated structures are modeled through the Abaqus software and the mass and stiffness matrices are extracted for the multimodal propagation. The multimodal wave number is presented and discussed for the travelling and evanescent modes.