In the present paper, we aim to analyze the effect of the design parameters of micro-textured sur... more In the present paper, we aim to analyze the effect of the design parameters of micro-textured surfaces on the anti-fingerprint function. For this purpose, a numerical model of the finger contact was developed to simulate the mechanical response of the finger loaded over differently micro-textured surfaces. Interestingly, this model enables the measurement of the touched area (i.e. stained area by fingerprints). A statistical analysis was conducted using a full factorial design in order to investigate the effect of the height, width and pitch describing the surface texture. The statistical significance of the parameters effects as well as the effects of their interactions was discussed. Results have shown that both the height and the interaction between the height and the pitch have significant influences on the real area of the finger contact. An optimal compromise between the height and the pitch is recommended to reduce the touched area. The obtained results highlighted by the statistical analyses can provide a guideline for the design of anti-fingerprint surfaces.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2019
In this paper, we have studied the effect of the degree of asymmetry and peakedness on the perfor... more In this paper, we have studied the effect of the degree of asymmetry and peakedness on the performances of a rough contact. A numerical model is proposed to evaluate the real area, the number of contacting asperities and the normal stiffness. The contact between two rough surfaces was modeled as a contact between a rigid flat and an elastic–plastic rough surface taking into account the work hardening and interaction among asperities. The Pearson system of frequency curves was used to generate non-Gaussian random surfaces. Results show that a negative skewness and/or a low kurtosis improve the contact performances by increasing the normal stiffness. This increase is governed by much more asperities into contact and more elastic behavior.
In this work, we investigate the effects of roughness level and asymmetry of profile on the mecha... more In this work, we investigate the effects of roughness level and asymmetry of profile on the mechanical behavior of an engineering surface. A numerical model was performed to simulate bi-dimensional surfaces with different roughness parameters (The arithmetic average height parameter Ra and skewness) values. This model predicts the contact load, real area and interfacial stiffness. It takes into account the elastic-plastic material behavior, asperities interactions and more realistic geometry than the analytical models. Both symmetric and asymmetric profiles were simulated. Symmetric (Gaussian) profiles were generated through experimentally measured surfaces. These profiles were artificially edited in order to put forward the effect of roughness parameters on the contact performances. The Pearson system of frequency curves is used to produce asymmetric profiles with the same roughness level. The effect of crushing and roughness level as well as the skewness parameter on the contact performance in terms of real area, contact load and interfacial stiffness was analyzed.
In order to accurately estimate the temperature reached in the cylinder block and cylinder head g... more In order to accurately estimate the temperature reached in the cylinder block and cylinder head gasket of an internal combustion engine, an experimental investigation of the thermal contact resistance (TCR) across cylinder head gasket is performed. TCR has been calculated for contact pressure up to 42 MPa which corresponds to the clamping pressure of the gasket. Different sections (inter-cylinders, oil, and water ribs) with different law behavior have been retained. The temperature evolution has been recorded using thermocouples immerged in the measurement device. The heat flux has been calculated using this temperature evolution. The TCR has been deduced using Fourier law. Results show that the TCR decreases with increasing the load and tends toward a constant value for various sections of the gasket. In addition, TCR values are more important for the inter-cylinder’s section which will result in greater values of temperature near inter-cylinder’s section on the cylinder block.
Recently, anti-fingerprint surfaces have attracted wide attention due to their self-clean and est... more Recently, anti-fingerprint surfaces have attracted wide attention due to their self-clean and esthetic performances. The surface texture is a determinant parameter that governs such properties. In this paper, the anti-fingerprint function of microstructured surfaces has been investigated. We have studied the effect of some topographic parameters on the mechanical behavior of the finger contact. Our analysis is mainly focused on the effect of the pitch value and the aspect ratio of the surface patterns on the anti-fingerprint function. A numerical approach has been employed to model dry contacts between the human fingertip and differently microstructured surfaces. The fingertip was modeled taking into account the topography of the finger skin (finger ridges) and the mechanical properties of the finger tissues. Results indicate that the pitch value has a critical effect on the anti-fingerprint function particularly for low aspect ratio surfaces. This highlights the relevance of the te...
This paper aims at investigating the production of high quality briquettes from olive mill solid ... more This paper aims at investigating the production of high quality briquettes from olive mill solid waste (OMSW) mixed with corn starch as a binder for energy production. For this purpose, different mass percentages of OMSW and binder were considered; 100%-0%, 90%-10%, 85%-15%, and 70%-30%, respectively. The briquetting process of the raw mixtures was carried out based on high pressures. Physico-chemical and mechanical characterizations were performed in order to select the best conditions for the briquettes production. It was observed that during the densification process, the optimal applied pressure increases notably the unit density, the bulk density, and the compressive strength. Mechanical characterization shows that the prepared sample with 15% of corn starch shows the best mechanical properties. Moreover, the corn starch binder affects quietly the high heating value (HHV) which increases from 16.36 MJ/Kg for the 100%-0% sample to 16.92 MJ/Kg for the 85%-15% sample. In addition,...
In the present paper, we aim to analyze the effect of the design parameters of micro-textured sur... more In the present paper, we aim to analyze the effect of the design parameters of micro-textured surfaces on the anti-fingerprint function. For this purpose, a numerical model of the finger contact was developed to simulate the mechanical response of the finger loaded over differently micro-textured surfaces. Interestingly, this model enables the measurement of the touched area (i.e. stained area by fingerprints). A statistical analysis was conducted using a full factorial design in order to investigate the effect of the height, width and pitch describing the surface texture. The statistical significance of the parameters effects as well as the effects of their interactions was discussed. Results have shown that both the height and the interaction between the height and the pitch have significant influences on the real area of the finger contact. An optimal compromise between the height and the pitch is recommended to reduce the touched area. The obtained results highlighted by the statistical analyses can provide a guideline for the design of anti-fingerprint surfaces.
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2019
In this paper, we have studied the effect of the degree of asymmetry and peakedness on the perfor... more In this paper, we have studied the effect of the degree of asymmetry and peakedness on the performances of a rough contact. A numerical model is proposed to evaluate the real area, the number of contacting asperities and the normal stiffness. The contact between two rough surfaces was modeled as a contact between a rigid flat and an elastic–plastic rough surface taking into account the work hardening and interaction among asperities. The Pearson system of frequency curves was used to generate non-Gaussian random surfaces. Results show that a negative skewness and/or a low kurtosis improve the contact performances by increasing the normal stiffness. This increase is governed by much more asperities into contact and more elastic behavior.
In this work, we investigate the effects of roughness level and asymmetry of profile on the mecha... more In this work, we investigate the effects of roughness level and asymmetry of profile on the mechanical behavior of an engineering surface. A numerical model was performed to simulate bi-dimensional surfaces with different roughness parameters (The arithmetic average height parameter Ra and skewness) values. This model predicts the contact load, real area and interfacial stiffness. It takes into account the elastic-plastic material behavior, asperities interactions and more realistic geometry than the analytical models. Both symmetric and asymmetric profiles were simulated. Symmetric (Gaussian) profiles were generated through experimentally measured surfaces. These profiles were artificially edited in order to put forward the effect of roughness parameters on the contact performances. The Pearson system of frequency curves is used to produce asymmetric profiles with the same roughness level. The effect of crushing and roughness level as well as the skewness parameter on the contact performance in terms of real area, contact load and interfacial stiffness was analyzed.
In order to accurately estimate the temperature reached in the cylinder block and cylinder head g... more In order to accurately estimate the temperature reached in the cylinder block and cylinder head gasket of an internal combustion engine, an experimental investigation of the thermal contact resistance (TCR) across cylinder head gasket is performed. TCR has been calculated for contact pressure up to 42 MPa which corresponds to the clamping pressure of the gasket. Different sections (inter-cylinders, oil, and water ribs) with different law behavior have been retained. The temperature evolution has been recorded using thermocouples immerged in the measurement device. The heat flux has been calculated using this temperature evolution. The TCR has been deduced using Fourier law. Results show that the TCR decreases with increasing the load and tends toward a constant value for various sections of the gasket. In addition, TCR values are more important for the inter-cylinder’s section which will result in greater values of temperature near inter-cylinder’s section on the cylinder block.
Recently, anti-fingerprint surfaces have attracted wide attention due to their self-clean and est... more Recently, anti-fingerprint surfaces have attracted wide attention due to their self-clean and esthetic performances. The surface texture is a determinant parameter that governs such properties. In this paper, the anti-fingerprint function of microstructured surfaces has been investigated. We have studied the effect of some topographic parameters on the mechanical behavior of the finger contact. Our analysis is mainly focused on the effect of the pitch value and the aspect ratio of the surface patterns on the anti-fingerprint function. A numerical approach has been employed to model dry contacts between the human fingertip and differently microstructured surfaces. The fingertip was modeled taking into account the topography of the finger skin (finger ridges) and the mechanical properties of the finger tissues. Results indicate that the pitch value has a critical effect on the anti-fingerprint function particularly for low aspect ratio surfaces. This highlights the relevance of the te...
This paper aims at investigating the production of high quality briquettes from olive mill solid ... more This paper aims at investigating the production of high quality briquettes from olive mill solid waste (OMSW) mixed with corn starch as a binder for energy production. For this purpose, different mass percentages of OMSW and binder were considered; 100%-0%, 90%-10%, 85%-15%, and 70%-30%, respectively. The briquetting process of the raw mixtures was carried out based on high pressures. Physico-chemical and mechanical characterizations were performed in order to select the best conditions for the briquettes production. It was observed that during the densification process, the optimal applied pressure increases notably the unit density, the bulk density, and the compressive strength. Mechanical characterization shows that the prepared sample with 15% of corn starch shows the best mechanical properties. Moreover, the corn starch binder affects quietly the high heating value (HHV) which increases from 16.36 MJ/Kg for the 100%-0% sample to 16.92 MJ/Kg for the 85%-15% sample. In addition,...
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Papers by Saoussen BELGHITH