Wyniki wyszukiwania - Biblioteka Nauki

1

Normal temperature mechanical properties of 6082 aluminium alloy as a function of tempering temperature: experimental and numerical approach

100%

Elhadi A. , Amroune S. , Houari A. , Kouder M.

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tom Vol. 18, no. 3

385--392

EN

Our study involved a combination of practical experiments and numerical simulations using the Abaqus computational software. The main aim was to enhance our understanding of the mechanical characteristics exhibited by 6082 aluminium alloy when exposed to tensile forces. To achieve this, we produced 18 samples of standardized dimensions utilizing a parallel lathe. These samples then underwent a thermal treatment comprising a solution treatment, water quenching and various tempering procedures at different temperatures (280°C, 240°C, 200°C, 160°C and 120°C), resulting in a range of hardness levels. To obtain the experimental results, we conducted tensile tests on a specialized machine, which were subsequently supplemented with numerical analyses. By adopting this approach, we gained valuable insights into the behaviour of aluminium alloy 6082, specifically regarding its mechanical properties such as hardness, tensile strength, elongation and necking coefficient. This newfound knowledge holds potential significance in the realm of designing and optimizing aluminium structures that operate within high-temperature environments.

2

Experimental investigations of surface wear by dry sliding and induced damage of medium carbon steel

88%

Elhadi A. , Amroune S. , Zaoui M. , Mohamad B. , Bouchoucha A.

Diagnostyka

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2021

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tom Vol. 22, No. 2

3--10

EN

This study concerns the wear behaviour of metal couples used in industry, particularly in mechanical sliding systems (numerically controlled machine tools). In general, the nature of the materials of the parts of these systems which are in contact and move relatively, are medium carbon steels, thanks to their good mechanical and tribological properties. The present work aims to study, the dry sliding wear of the contact surface of the pin (machine slide) against the contact surface of a disc (machine groove) and the damage induced on the worn track. The pin is AISI 1038 and AISI 1045 steel, the disc is AISI 1055 steel. The tribological tests were carried out on a pin-disc tribometer, in an atmospheric environment. The wear of the pins being evaluated by weighing and studied according to the hardness of the pin with the variation of the normal load applied. The discussion of the results is based on SEM observations and EDS analyzes of worn surfaces and interfacial phenomena produced by dynamic contact. The results obtained indicated the influence of the applied load and the hardness on the wear of the pin and therefore on the tribological behaviour of the worn surfaces.

3

Fluid dynamic and acoustic optimization methodology of a formula-student race car engine exhaust system using multilevel numerical CFD models

88%

Mohamad B. , Ali M. Q. , Neamah H. A. , Zelentsov A. , Amroune S.

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tom Vol. 21, No. 3

103--111

EN

In this work a multilevel CFD analysis have been applied for the design of an engine exhaust system include manifold and muffler with improved characteristics of noise reduction and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model and 3D tools. Once the best configuration has been defined, the 1D-3D approach has been adopted to confirm the prediction carried out by means of the simplified approach, studying also the impact of the new configuration on the engine performances.

4

Experimental and numerical study of the effect of the presence of a geometric discontinuity of variable shape on the tensile strength of an epoxy polymer

75%

Saada K. , Amroune S. , Zaoui M. , Houari A. , Madani K. , Hachaichi A.

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2023

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tom Vol. 17, no. 2

192--199

EN

The presence of geometric discontinuity in a material reduces considerably its resistance to mechanical stresses, therefore reducing the service life of materials. The analysis of structural behaviour in the presence of geometric discontinuities is important to ensure the proper use, especially if it is regarding a material of weak mechanical properties such as a polymer. The objective of the present work is to analyse the effect of the notch presence of variable geometric shapes on the tensile strength of epoxy-type polymer specimens. A series of tensile tests were carried out on standardised specimens, taking into account the presence or absence of a notch. Each series of tests contains five specimens. Two notch shapes were considered: circular (hole) and elliptical. The experimental results in terms of stress–strain clearly show that the presence of notches reduces considerably the resistance of the material, where the maximum stress for the undamaged specimen was 41.22 MPa and the lowest stress for the elliptical-notched specimen was 11.21 MPa. A numerical analysis by the extended finite element method (XFEM) was undertaken on the same geometric models; in addition, the results in stress–strain form were validated with the experimental results. A remarkable improvement was obtained (generally an error within 0.06%) for strain, maximum stress, Young’s modulus and elongation values. An exponential decrease was noted in the stress, strain, and Young’s modulus in the presence of a notch in the material.

5

New approach for computer-aided static balancing of turbines rotors

75%

Amroune S. , Belaadi A. , Menasri N. , Zaoui M. , Mohamad B. , Amin H.

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2019

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tom Vol. 20, No. 4

95--101

EN

The balancing operation consists in improving the distribution of the rotor masses so that the free centrifugal forces around the rotor axis, imposed by the manufacturer, do not exceed the tolerances allowed by the standards. In this paper we propose algorithms for the distribution of the turbine blades from data from an electronic scale which allows to measure the static moment of the blades, these algorithms aim to find the correction weight and the angle of position of the correction mass, we also propose a simulation of the distribution of the blades of a turbine to get an idea on the assembly. This operation is necessary in the case of a repair of the rotors or in the assembly of the new flexible rotors. Using a MATLAB calculation code.

6

Experimental investigation into the tensile strength post-repair on damaged aluminium 2024 - T3 plates using hybrid bonding/riveting

63%

Merah A. A. , Houari A. , Madani K. , Belhouari M. , Amroune S. , Chellil A. , Yahia C. Z. , Campilho R. D. S. G.

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tom Vol. 18, no. 3

514--525

EN

Since the implementation of repair processes by composite patch bonding, this process has consistently demonstrated high performance across various industrial sectors, especially in the fields of aeronautics, aerospace and civil engineering. Consequently, there are situations in which the riveting process becomes the sole solution, particularly when the structure is subjected to severe mechanical or thermo-mechanical stresses, since adhesives have low mechanical strength after aging. Each method has its own set of advantages and disadvantages. The current trend is to combine these two processes to minimise their drawbacks as much as possible. The objective of this work is to present an experimental study on the repair of an aluminium plate AL2024-T3 with a central circular notch using a patch of different nature (metal or composite), under tensile loading conditions. The repair composite considered is a carbon/epoxide. The results of the tensile tests showed that the repair by the combination of the two processes improves the mechanical strength of the damaged structure. A comparison of the results of the experimental curves obtained on riveted, bonded and hybrid assemblies has been taken into consideration.