https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 09 Jun 2026 20:43:55 GMT 2026-06-09T20:43:55Z http://hdl.handle.net/10985/22516 Identification of the elastic-plastic properties of CrN coating on elastic-plastic substrate by nanoindentation using finite element method-reverse algorithm BEN AMMAR, Yamen; AOUADI, Khalil; NOUVEAU, Corinne; BESNARD, Aurélien; MONTAGNE, Alex This paper proposes an identification methodology based on nanoindentation analysis of coating/substrate system to extract the elastic-plastic properties of coating materials on elastic-plastic substrate when the indenter penetration depth is greater than the film thickness. In order to accurately predict the elastic-plastic properties of the coating materials, a trust-region reflective optimization algorithm is integrated with the finite element analysis, in cooperation with the Jönsson and Hogmark model. The proposed reverse analysis algorithm modifies a predicted load-displacement (P-h) curve by changing the elastic-plastic properties of the coating and the substrate until it fits the experimental nanoindentation (P-h) curve. Numerical and instrumental indentations tests were carried out on a CrN film/Martensitic stainless steel substrate system to verify the proposed reverse method, by which Young's modulus (E), yield stress (σy), and work hardening exponent of the film were obtained. A sensitivity analysis is conducted to study the effect of the elastic-plastic properties of the CrN film/substrate on the (P-h) curve. The results showed a high impact to the loading and unloading part of the (P-h) curve due to variations in (E) and (σy) of the steel substrate compared to those of the CrN coating. Sun, 26 Jun 2022 00:00:00 GMT http://hdl.handle.net/10985/22516 2022-06-26T00:00:00Z BEN AMMAR, Yamen AOUADI, Khalil NOUVEAU, Corinne BESNARD, Aurélien MONTAGNE, Alex This paper proposes an identification methodology based on nanoindentation analysis of coating/substrate system to extract the elastic-plastic properties of coating materials on elastic-plastic substrate when the indenter penetration depth is greater than the film thickness. In order to accurately predict the elastic-plastic properties of the coating materials, a trust-region reflective optimization algorithm is integrated with the finite element analysis, in cooperation with the Jönsson and Hogmark model. The proposed reverse analysis algorithm modifies a predicted load-displacement (P-h) curve by changing the elastic-plastic properties of the coating and the substrate until it fits the experimental nanoindentation (P-h) curve. Numerical and instrumental indentations tests were carried out on a CrN film/Martensitic stainless steel substrate system to verify the proposed reverse method, by which Young's modulus (E), yield stress (σy), and work hardening exponent of the film were obtained. A sensitivity analysis is conducted to study the effect of the elastic-plastic properties of the CrN film/substrate on the (P-h) curve. The results showed a high impact to the loading and unloading part of the (P-h) curve due to variations in (E) and (σy) of the steel substrate compared to those of the CrN coating. 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/10985/26943 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.