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HYDRODYNAMIC AND ELASTOHYDRODYNAMIC STUDIES OF A CYLINDRICAL JOURNAL BEARING

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Journal of Hydrodynamics 2010年第2期22卷 155-163页

作者： ATTIA HILI Molka BOUAZIZ Slim MAATAR mohamed FAKHFAKH Tahar haddar mohamed Mechanics Modelling and Production Research Unit (U2MP)National School of Engineers of Sfax(ENIS)BP.11733038sfaxTunisia

In this article,the effect of the bearing elastic deformation on the performance characteristics of a cylindrical journal bearing is *** variety of simulation models covers hydrodynamic（HD） and elastohydrodynamic（EHD） lubrication *** Reynolds equations governing the flow in the clearance space of the journal bearing are obtained by considering the effect of mass transfer across the fluid *** finite element method with an iteration scheme was employed to solve both the Reynolds equation and the three-dimensional elasticity equation representing the displacement field in the bearing *** converged solutions for the lubricant flow and elastic deformation vector are *** characteristics of the journal bearing are computed for HD and EHD *** simulation results show that the flexibility of bearing liner has a significant influence on the performance of a cylindrical journal ***,the elastic deformations of the bearing liner extend the pressure area in the bearing and increase the minimum film ***,dynamic coefficient,load capacity and attitude angle decrease.

关键词： Reynolds equation hydrodynamic(HD) and elastohydrodynamic(EHD) lubrication theories dynamic coefficients relative eccentricity deformation coefficient

Damping Analysis and Failure Mechanism of 3D Printed Bio-Based Sandwich with Auxetic Core under Bending Fatigue Loading

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Journal of Renewable Materials 2021年第3期9卷 569-584页

作者： Khawla Essassi Jean-Luc Rebiere Abderrahim El Mahi mohamed Amine Ben Souf Anas Bouguecha mohamed haddar Acoustics Laboratory of Mans University(LAUM)-UMR CNRS Le Mans UniversityLe Mans6613France Laboratory of Mechanics Modeling and Production(LA2MP) National School of Engineers of SfaxUniversity of SfaxSfaxTunisia

Meta-sandwich composites with three-dimensional(3D)printed architecture structure are characterized by their high ability to absorb *** this paper,static and fatigue 3-point bending tests are implemented on a 3D printed sandwich composites with a re-entrant honeycomb *** skins,core and whole sandwich are manufactured using the same bio-based material which is polylactic acid with flax fiber *** tests are performed in order to evaluate the durability and the ability of this material to dissipate ***,static tests are conducted to study the bending behaviour of the sandwich beams,as well as to determine the failure parameters and the characteristic used in fatigue ***,fatigue analyses were carried out to determine the fatigue resistance of these *** effects of the core density on the stiffness,hysteresis loop,energy absorption and loss factor,for two loading level,are ***,the behaviour of this sandwich composite with re-entrant honeycomb core is compared with that of sandwiches with different core *** results show that sandwich with high core density dissipate more energy,which results higher loss *** determined properties offer the most sensitive indicators of sandwich composite damage during its *** work aims to determine the static and fatigue properties of this material,thus,study its potential applications in industry.

关键词： Auxetic structure fatigue damping bio-sandwich composite 3D printing

Topological Modeling of a One Stage Spur Gear Transmission

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 900-908页

作者： MILADI CHAABANE Mariem PLATEAUX Régis CHOLEY Jean-Yves KARRA Chafik RIVIERE Alain haddar mohamed Mechanical Modeling and Manufacturing Unit National Engineering School of Sfax(ENIS) BP 1173 – 3038 – Sfax – Tunisia Laboratory of Engineering of the Mechanical Structures and Materials High Institute of Mechanic of Paris(SUPMECA)3 rue Fernand HainautNational 93407 Saint-Ouen Cedex Mechanical Modeling and Manufacturing Unit National Engineering School of Sfax(ENIS) BP 1173–3038–Sfax–Tunisia

Finding a basis of unification for the modeling of mechatronic systems is the search subject of several *** paper is a part of a general research designed to the application of topology as a new approach for the modeling of mechatronic ***,the modeling of a one stage spur gear transmission using a topological approach is *** approach is based on the concepts of topological collections and transformations and implemented using the MGS（modeling of general systems）*** topological collections are used to specify the interconnection laws of the one stage spur gear transmission and the transformations are used to specify the local behavior laws of its different *** order to validate this approach,simulation results are presented and compared with those obtained with MODELICA language using Dymola *** good results are achieved,this approach might be used as a basis of unification for the modeling of mechatronic systems.

关键词： topological modeling topological collections transformations MGS language one stage spur gear

Effect of Recycling Cycles on the Mechanical and Damping Properties of Flax Fibre Reinforced Elium Composite:Experimental and Numerical Studies

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Journal of Renewable Materials 2021年第4期9卷 695-721页

作者： Sami Allagui Abderrahim El Mahi Jean-Luc Rebiere Moez Beyaoui Anas Bouguecha mohamed haddar Acoustics Laboratory of Le Mans University Le Mans UniversityLe Mans72085France Laboratory of Mechanics Modelling and Production National School of Engineering of SfaxSfax3038Tunisia

This manuscript deals with the effects of recycling on the static and dynamic properties of flax fibers reinforced thermoplastic *** corresponding thermoplastic used in this work is Elium ***’s the first liquid thermoplastic resin that allows the production of recycled composite parts with promising mechanical *** appeared on the resin market in *** until now,no studies were available concerning how it can be recycled and *** this study,a thermocompression recycling process was investigated and applied to Elium *** fiber-reinforced Elium composites were produced using a resin infusion process and were subjected to different thermomechanical recycling *** each material,five recycling operations were carried out on the raw material.A total of 10 different materials were investigated and tested by means of tensile and free vibration tests to evaluate the effect of recycling on their *** addition,a finite element model of the dynamic problem was developed to evaluate the loss factor and natural frequencies regarding different *** results obtained show that the failure tensile properties of Elium resin as well as flax fiber reinforced composites decrease during recycling ***,recycling induces a rise in the elastic ***,improvement in the dynamic stiffness was observed with recycling *** repeated recycling appeared to have negligible effects on the loss factor of the recycled *** results obtained from the experiment and the numerical analyses were in close agreement.

关键词： Recycling thermoplastic bio-composites thermocompression process tensile properties vibration loss factor

Analysis of the Manufactured Tolerances with the Three-Dimensional Method of Angular Chains of Dimensions Applied to a Cylinder Head of Car Engine

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Engineering（科研） 2010年第10期2卷 771-779页

作者： Aida Mezghani Alain Bellacicco Jamel Louati Alain Rivière mohamed haddar 不详

This paper proposes an analysis method of the manufactured tolerances applied to a cylinder head of car engine. This method allows to determine the manufacturing tolerances in the case of angular chains of dimensions and to check its correspondence with the functional tolerances. The objective of this work is to analyze two parameterized functions: the angular defect Δα and the projected length lg of the toleranced surface. The angular defects are determined from the precision of the machine tools, we consider only the geometrical defects (position and orientation of surfaces), making the assumption that the form defects are negligible. The manufactured defect is determined from these two parameterized functions. Then it will be compared with the functional condition in order to check if the selected machining range allows, at end of the manufacturing process, to give a suitable part.

关键词： Three-Dimensional Tolerancing Manufacturing Process Toleranced Surface Angular Defect

Influence of Cutting and Geometrical Parameters on the Cutting Force in Milling

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Engineering（科研） 2010年第10期2卷 751-761页

作者： Hedi Yangui Bacem Zghal Amir Kessentini Gael Chevallier Alain Riviere mohamed haddar Chafik Karra Unite de Mecanique Modélisation et Production(U2MP)Ecole Nationale d’Ingénieurs de Sfax(E.N.I.S.)route soukra km 4 Sfax–TUNISIEFrance Laboratoire d’Ingénierie des Structures Mécanique et de Matériaux(LISMMA) Institut Supérieur de Mécanique de Paris(SUPMECA)3 rue Fernand Hainaut93407 cedex Saint ouenParis–France

This paper presents a numerical modelling of the dynamic behaviour of the Machine-Tool-Part system (MOP) in milling. The numerical study of such complex structure requires the use of sophisticated method like finite elements one. Simulation is employed to predict cutting forces and dynamic response of Machine-Tool-Part system (MOP) during end-milling operation. Finally, spectral analysis is presented to see the influence of feed direction in the vibration.

关键词： Milling Modelling Cutting Force Finite Element

A Challenging Approach to Improve the Low Affinity of Acrylic Fibres to Be Successfully Dyed with a Bio-Colorant Extracted from Grape Marc

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Journal of Renewable Materials 2019年第3期7卷 289-300页

作者： Noureddine Baaka Manel Ben Ticha Wafa haddar mohamed Farouk Mhenni University of Monastir Faculty of Sciences of MonastirResearch Unity of Applied Chemistry and Environment5000 MonastirTunisia National Engineering School of Monastir 5019 MonastirTunisia Higher Institute of Technological Studies 5070Ksar HellalMonastirTunisia

Acrylic fibres are highly crystalline and non-polar polymers,which makes their dyeing a very difficult step that poses real technical *** order to overcome this concern,it is intended in this paper to modify acrylic fibers by different methods namely cationisation using the Crosscolor DRT then amidoximation using hydroxylamine hydrochloride and ammonium *** resulted samples were dyed then with the bio-colorant extracted from grape *** effect of the pretreatment on fibers fine structure using X-ray diffraction and the scanning electron microscope(SEM)images and its correlation with the colour strength of the dyed fabrics was *** dyeing parameters,such as dye bath pH and temperature on the performances of this dyeing process were *** dyeing qualities and new shades varying from brown to grey and dark green have been obtained following process optimization,mordanting and modification of acrylic fibers by the technique of cationisation.

关键词： Modified acrylic fibers grape marc bio-colorant mordant.