H. Kebir

Publications

6 Condition Monitoring for Controlling the Stability of the Rotating Machinery

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, I. Gahlouz, S. Chellil

Abstract:

In this paper, the experimental study for the instability of a separator rotor is presented, under dynamic loading response in the harmonic analysis condition. The global measurement and analysis of vibration on the cement separator RC500 is carried, the points of measurement used are radial dots, vertical, horizontal and oblique. The measures of trends and spectral analysis for reconnaissance of the main anomalies, the main defects in the separator and manifestation, the results prove that the defects effect has a negative effect on the stability of the rotor. Experimentally the study of the rotor in transient system allowed to determine the vibratory responses due to the unbalances and various excitations.

Keywords: Experimental, Frequency, defect, rotor, specter

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5 Composite Patch Repair of Central Crack Growth in Aluminium Alloy Plate

Authors: S. Lecheb, A. Chellil, H. Mechakra, H. Kebir, A. Zeggane

Abstract:

In this work, repaired crack in 6061- T6 aluminum plate with composite patches presented, firstly we determine the displacement, strain and stress, also the first six mode shape of the plate, secondly we took the same model adding central crack initiation, which is located in the center of the plate, its seize vary from 20 mm to 60 mm and we compare the first results with second. Thirdly we repair various cracks with composite patch (carbon/ epoxy) and for (2 layers, 4 layers). Finally the comparison of stress, strain, displacement and six first natural frequencies between un-cracked specimen, crack propagation and composite patch repair.

Keywords: stress, crack growth, composite patch repair, aluminum alloy plate

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4 Numerical Study for Structural Design of Composite Rotor with Crack Initiation

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, A. Bouderba

Abstract:

In this paper, a coupled damage effect in the instability of a composite rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor blade are developed. The use of the composite material for the rotor offers a good stability. Numerical calculations on the model developed prove that the damage effect has a negative effect on the stability of the rotor. The study of the composite rotor in transient system allowed determining the vibratory responses due to various excitations.

Keywords: Composite, Numerical, Damage, finite element, rotor

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3 Behavior Fatigue Life of Wind Turbine Rotor with Longitudinal Crack Growth

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, N. Hamad, H. Kebir

Abstract:

This study concerned the dynamic behavior of the wind turbine rotor. Before all we have studied the loads applied to the rotor, which allows the knowledge their effect on the fatigue, also studied the rotor with longitudinal crack in order to determine stress, strain and displacement. Firstly we compared the first six modes shapes between cracking and uncracking of HAWT rotor. Secondly we show show evolution of first six natural frequencies with longitudinal crack propagation. Finally we conclude that the residual change in the natural frequencies can be used as in shaft crack diagnosis predictive maintenance.

Keywords: natural frequencies, life time, wind turbine rotor, longitudinal crack growth

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2 Stress Intensity Factor for Dynamic Cracking of Composite Material by X-FEM Method

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, N. Hamad, H. Kebir

Abstract:

The work involves develops attended by a numerical execution of the eXtend Finite Element Method premises a measurement by the fracture process cracked so many cracked plates an application will be processed for the calculation of the stress intensity factor SIF. In the first we give in statically part the distribution of stress, displacement field and strain of composite plate in two cases uncrack/edge crack, also in dynamical part the first six modes shape. Secondly, we calculate Stress Intensity Factor SIF for different orientation angle θ of central crack with length (2a=0.4mm) in plan strain condition, KI and KII are obtained for mode I and mode II respectively using X-FEM method. Finally from crack inclined involving mixed modes results, the comparison we chose dangerous inclination and the best crack angle when K is minimal.

Keywords: stress intensity factor (SIF), crack orientation, glass/epoxy, natural frequencies, X-FEM

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1 Mechanical Characteristics on Fatigue Crack Propagation in Aluminium Plate

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, L. Addar

Abstract:

This paper present a mechanical characteristics on fatigue crack propagation in Aluminium Plate based on strain and stress distribution using the abaqus software. The changes in shear strain and stress distribution during the fatigue cycle with crack growth is identified. In progressive crack in the strain distribution and the stress is increase in the critical zone. Numerical Modal analysis of the model developed, prove that the Eigen frequencies of aluminium plate were decreased after cracking, and this reduce is nonlinear. These results can provide a reference for analysts and designers of aluminium alloys in aeronautical systems.

Therefore, the modal analysis is an important factor for monitoring the aeronautic structures.

Keywords: Aluminium Alloys, Failure, Plate, crack

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Abstracts

9 Fracture and Dynamic Behavior of Leaf Spring Suspension

Authors: S. Lecheb, A. Chellil, H. Mechakra, H. Kebir, S. Attou

Abstract:

Although leaf springs are one of the oldest suspension components they are still frequently used, especially in commercial vehicles. Being able to capture the leaf spring characteristics is of significant importance for vehicle handling dynamics studies. The main function of leaf spring is not only to support vertical load but also to isolate road induced vibrations. It is subjected to millions of load cycles leading to fatigue failure. It needs to have excellent fatigue life. The objective of this work is its use of Abaqus software to locate the most stressed areas and predict the areas in which it occurs in fatigue and crack of leaf spring and calculate the stress and frequencies of this model.

Keywords: stress, crack, natural frequencies, leaf spring

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8 Condition Monitoring for Controlling the Stability of the Rotating Machinery

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, I. Gahlouz, S. Chellil

Abstract:

In this paper, the experimental study for the instability of a separator rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor are developed. Numerical calculations on the model develop of three dimensions prove that the defects effect has a negative effect on the stability of the rotor. Experimentally, the study of the rotor in the transient system allowed to determine the vibratory responses due to the unbalances and various excitations.

Keywords: Frequency, finite element, rotor, specter

Procedia PDF Downloads 204
7 Repair of Cracked Aluminum Plate by Composite Patch

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, A. Zeggane

Abstract:

In this work, repaired crack in 6061-T6 aluminum plate with composite patches presented, firstly we determine the displacement, strain, and stress, also the first six mode shape of the plate, secondly we took the same model adding central crack initiation, which is located in the center of the plate, its size vary from 20 mm to 60 mm and we compare the first results with second. Thirdly, we repair various cracks with the composite patch (carbon/epoxy) and for (2 layers, 4 layers). Finally, the comparison of stress, strain, displacement and six first natural frequencies between un-cracked specimen, crack propagation and composite patch repair.

Keywords: stress, crack growth, composite patch repair, aluminum alloy plate

Procedia PDF Downloads 443
6 Numerical Study for Structural Design of Composite Rotor with Crack Initiation

Authors: S. Lecheb, A. Nour, A. Chellil, H. Kebir, A. Bouderba, H.Mechakra

Abstract:

In this paper, the numerical study for the instability of a composite rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor is developed. The use of the composite material for the rotor, offers a good Stability. Numerical calculations on the model develop of three dimensions prove that the damage effect has a negative effect on the stability of the rotor. The study of the composite rotor in transient system allowed to determine the vibratory responses due to various excitations.

Keywords: Composite, Numerical, Damage, finite element, rotor

Procedia PDF Downloads 326
5 Behavior Fatigue Life of Wind Turbine Rotor with Longitudinal Crack Growth

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, N. Tchina

Abstract:

This study concerned the dynamic behavior of the wind turbine rotor. Before all, we have studied the loads applied to the rotor, which allows the knowledge their effect on the fatigue. We also studied the movement of the longitudinal cracked rotor in order to determine stress, strain and displacement. Moreover, to study the issues of cracks in the critical zone ABAQUS software is used, which based to the finite element to give the results. In the first we compared the first six modes shapes between cracking and uncracking of HAWT rotor. In the second part, we show the evolution of six first naturals frequencies with longitudinal crack propagation. Finally, we conclude that the residual change in the naturals frequencies can be used as in shaft crack diagnosis predictive maintenance.

Keywords: natural frequencies, life time, wind turbine rotor, longitudinal crack growth

Procedia PDF Downloads 444
4 Numerical and Experimental Analysis of Rotor Dynamic Stability

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, A. Bouderba

Abstract:

The study of the rotor dynamic in transient system allowed to determine the vibratory responses due to various excitations. This work presents a coupled gyroscopic effect in the defects of a rotor under dynamic loading. Calculations of different energies and virtual work from the various elements of the rotor are developed. To treat real systems a model of finite element was developed. This model of the rotor makes it possible to extract the frequencies and modal deformed, and to calculate the stresses in the critical zone. The study of the rotor in transient system allowed to determine the vibratory responses due to the unbalances, crack and various excitations.

Keywords: Numerical, finite element, defect, rotor

Procedia PDF Downloads 255
3 Dynamic Analysis and Instability of a Rotating Composite Rotor

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, A. Bouderba

Abstract:

In this paper, the dynamic response for the instability of a composite rotor is presented, under dynamic loading response in the harmonic analysis condition. The analysis of the stress which operates the rotor is done. Calculations of different energies and the virtual work of the aerodynamic loads from the rotor blade is developed. The use of the composite material for the rotor, offers a good stability. Numerical calculations on the model develop of three dimensions prove that the damage effect has a negative effect on the stability of the rotor. The study of the composite rotor in transient system allowed to determine the vibratory responses due to various excitations.

Keywords: Composite, Numerical, Damage, finite element, rotor

Procedia PDF Downloads 377
2 Mechanical Characteristics on Fatigue Crack Propagation in Aluminum Plate

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, H. Kebir, L. Addar

Abstract:

This paper present a mechanical characteristics on fatigue crack propagation in Aluminium Plate based on strain and stress distribution using the abaqus software. The changes in shear strain and stress distribution during the fatigue cycle with crack growth is identified. In progressive crack in the strain distribution and the stress is increase in the critical zone. Numerical Modal analysis of the model developed, prove that the Eigen frequencies of aluminium plate were decreased after cracking, and this reduce is nonlinear. These results can provide a reference for analysts and designers of aluminium alloys in aeronautical systems. Therefore, the modal analysis is an important factor for monitoring the aeronautic structures.

Keywords: Aluminum Alloys, Failure, Plate, crack

Procedia PDF Downloads 284
1 Stress Intensity Factor for Dynamic Cracking of Composite Material by X-FEM Method

Authors: S. Lecheb, A. Nour, A. Chellil, H. Mechakra, N. Hamad, H. Kebir

Abstract:

The work involves develops attended by a numerical execution of the eXtend Finite Element Method premises a measurement by the fracture process cracked so many cracked plates an application will be processed for the calculation of the stress intensity factor SIF. In the first we give in statically part the distribution of stress, displacement field and strain of composite plate in two cases uncrack/edge crack, also in dynamical part the first six modes shape. Secondly, we calculate Stress Intensity Factor SIF for different orientation angle θ of central crack with length (2a=0.4mm) in plan strain condition, KI and KII are obtained for mode I and mode II respectively using X-FEM method. Finally from crack inclined involving mixed modes results, the comparison we chose dangerous inclination and the best crack angle when K is minimal.

Keywords: stress intensity factor (SIF), crack orientation, glass/epoxy, natural frequencies, X-FEM

Procedia PDF Downloads 361