Moez Abdennadher

• Professor (Associate) at University of Sfax

Most of the researches works describe powertrain models under stationary operating conditions. However, the stationary assumption cannot always be true because during operation, the speed and the charge conditions are fluctuating. In this paper, dynamic behavior of nonlinear powertrain model under acyclism condition and the effect of cracked gear t...

Misalignment fault is a common source that generates strong vibrations and even dysfunction in rotating machinery. However, the characteristics of the dynamic response and the modeling of this type of defect have not been fully understood and there remains today an attractive field of research. This paper sheds the light on the modeling of vibratio...

Different types of tuned mass dampers (TMD) have been used to reduce vibrations in several domains. In this paper, we studied the effect of parameter values of a pendulum tuned mass damper (PTMD) on the dynamic behaviour of a structure. The two-dimensional developed model consist of both planar and spherical motions of our PTMD. The mass of pendulu...

The aim of the present study is to investigate the mechanical behavior of carbon/flax hybrid composites under static and fatigue tensile loading. The failure characteristics and parameters used in the fatigue tests were deduced from the static ones. The effect of the applied stress level, hybridization and stacking sequences on the stiffness, hyste...

There are several types of renewable energy, produced from different sources. One of the most efficient renewable today is the wind energy. In the case of wind power, the kinetic energy of the wind drives a generator which produces electricity. The drive train is an important component in realizing reliable and robust wind turbines. This research w...

The application of friction mechanisms is found in many areas such as automobile disc brakes. The study of these systems presents some complexity due to the large number of components and parameters included. In this paper a mathematical mechanical modeling of disc brake squeal with multi friction contacts points is developed. Besides, an analysis...

Non-linear dynamic problems are difficult to analyze since no general methods exist to deal with them, which namely depend on several factors such as the nature of the problem, the type of non-linearity or the type of solution to be sought. While some methods are used to study weak nonlinearities, others can more easily solve strong nonlinearities....

Wind turbines have been used for decades in order to produce electricity. Its main advantage is that its energy is clean, does not harm the nature and maintains its balance. For this reason, researchers and engineers have been focused on improving its design, performance and reliability. In addition, its condition monitoring has been studied for ma...

The purpose of the present work is to investigate experimentally the mechanical fatigue behavior of unidirectional flax and carbon fiber reinforced composites. Static and fatigue bending tests were realized on laminates made of flax and carbon fibers impregnated with an epoxy resin. Displacement-controlled bending fatigue tests were conducted on st...

Friction-induced vibration can be defined as a type of dynamic instability problem. Generally, engineers and researchers working in the field of noisy disc brakes treat instabilities due to a friction force as self-excited vibrations. The most known case is squealing. For disc brake mechanisms, mode coupling is responsible for generating annoying s...

Ces derniers jours, plusieurs industries se sont concentrées sur les matériaux légers et écologiques, dotés de bonnes propriétés mécaniques et amortissantes. Les composites renforcés de fibres de lin ont fait leur preuve dans le domaine de la dynamique en présentant des performances élevées en amortissement des vibrations. Néanmoins, leurs caractér...

The objective of the present experimental work is to determine the damage mechanisms appearing in unidirectional carbon/flax hybrid composites during tensile tests. The specimens tested consist of unidirectional carbon and flax fiber plies with different stacking sequences. Laminated composites were manufactured using a manual lay-up process. The s...

The brake squeal reduction has been extensively investigated in many academic and industrial researchers. Friction-induced vibrations can be considered as a dynamic instability problem. Generally, automotive engineers and researchers working in the domain of disk brake noise treat instabilities due to the force of friction as a friction-induced vib...

Gears are an important element in a variety of industrial applications. An unexpected failure of the gear may cause significant economic losses. For that reason, fault diagnosis in gears has been the subject of intensive research. Modal analysis can be used in the fault detection of rotating machinery. It can provide natural frequencies and vibrati...

Hybridation of carbon fiber composites with flax fiber offer interesting bio-degradability, respect of the environment, reduced cost and important dynamic properties. The purpose of this work is to study the effect of hybridation on the mechanical fatigue behavior of unidirectional carbon-flax hybrid composites. Static and fatigue tensile tests wer...

The purpose of the present experimental study is to describe the damage mechanisms occurring in epoxy matrix composites reinforced with hybrid carbon-flax fibres. The samples tested were consist of unidirectional carbon and flax fibre plies with different stacking sequences. Composite laminates were manufactured by hand lay-up process. The specimen...

This paper presents an investigation of the effect of stacking sequences on the damping behaviour of carbon-flax hybrid composites. The two different stacking sequences ([C/F2]s and [F2/C]s) studied are made with unidirectional carbon and flax fibres impregnated with epoxy resin. The manufacturing technique used for preparing the composite laminate...

Real applications in mechanical systems where the dynamic behaviour is linear are rare. Generally, friction systems such as disc brake have behaviour may be highly nonlinear. In this paper, A combined Harmonic Balance /alternating frequency time (HBM-AFT) method coupled with an arc length continuation algorithm is developed and used for the predict...

The purpose of the present experimental study is to describe the damage mechanisms occurring in epoxy matrix composites reinforced with hybrid carbon-flax fibres. The samples tested were consist of unidirectional carbon and flax fibre plies with different stacking sequences. Composite laminates were manufactured by hand lay-up process. The specimen...

Reducing or eliminate noise of a brake system caused by vibration is a challenge in the automotive industry. The disc brake squealing is a noise that occurs through high frequency vibrations in the brakes. In spite of the different works that deal with this problem, it remains, up to now, a large field of research thanks to the complexity of the sy...

The dynamic modeling of vibration of a drivetrain is used for increasing our information about vibration generating mechanisms, especially in the presence of some kind of gear faults. This paper describes a research work on the automotive driveline modeling, vibration analysis, and the effect of gear defects on the dynamic behavior of the system. F...

The purpose of the present paper is to study the effect of hybridation, stacking sequences and fiber orientation on the damping properties of unidirectional carbon/flax fiber reinforced epoxy composites. Non-hybrid and hybrid laminates with different stacking sequences were produced by molding vacuum process. Free vibration tests with an impulse te...

Ce travail présente une étude expérimentale du comportement vibratoire des composites stratifiés à fibres hybrides lin/carbone et à matrice époxy. Le principal objectif de cette étude consiste à analyser l’effet de l’hybridation, la séquence d’empilement et l’orientation des fibres sur les propriétés dynamiques des matériaux composites à fibres lin...

Wind energy is one of the most efficient renewable energies. The drive train is an important component in realizing reliable and robust wind turbines. This paper studies the dynamic behavior of a wind turbine drivetrain under different excitation sources. The present research work developed a 11-DOF dynamic model of a wind turbine drivetrain. This...

Les composites à fibres de lin ont fait leur preuve dans le domaine de la dynamique en présentant des bonnes performances. Néanmoins, les propriétés dynamiques des composites à fibres de carbone sont nettement moins importantes. De ce fait, l’objectif de cette étude consiste à améliorer leurs comportements dynamiques en exploitant la technique d’hy...

In this paper, the vibro-acoustic behaviour of a laminated glass plate composed of two elastic skins, a viscoelastic core and two ultra-thin adhesive films; is investigated. Here, the coupled dynamic model is derived by mixing the classical plate's theories (Mindlin and Kirchhoff models) and the specific behaviour law for the ultra-thin films, prev...

The harmonic Balance method (HBM) is an analytical method for solving nonlinear dynamic systems in the frequency domain when the response is periodic over time. Several variations on the classical HBM, such as the incremental harmonic balance IHB or the alternating frequency/time domain AFT have been presented in the literature to calculate the per...

In this paper, a dynamic study is carried out for a new laminated glass plate which contains two elastic skins, a viscoelastic core and two adhesives films supposed to be ultra-thin layers; and which can be used for the assembly of the laminated structure. In this case, the coupling between all layers is modelled by taking into account the interfac...

Drivetrain vibrations are a great concern in the automotive industry, once they are related to many Noise, Vibration and Harshness (NVH) phenomena. An automobile drivetrain system generally consists of the following main components: engine, clutch, gearbox, disk brake, and transmission shafts. This paper represents a nonlinear dynamic model for eac...

The present paper is aimed at the application of a substructure methodology, based on the Frequency Response Function (FRF) simulation technique, to analyze the vibration of a stage reducer connected by a rigid coupling to a planetary gear system. The computation of the vibration response was achieved using the FRF-based substructuring method. Firs...

A generalized dynamic model for an automotive drive train system was detailed to investigate its modal properties and dynamic behavior. The model's engine excitation, clutch, gearbox and disc brake were presented. Then, vibration modes were obtained and classified into clutch, transmission system, disc brake, bearing and combined modes. For each vi...

This paper deals with a new numerical model for predicting the dynamical behaviour of a laminated plate composed of two glass skins and a viscoelastic core (PVB: butyral polyvinyl) assembled by two adhesive ultra-thin films. In order to introduce the effect of the ultra-thin films, some suggestions are considered in the kinematic hypothesis. Theref...

The book provides readers with a snapshot of recent research and industrial trends in field of industrial acoustics and vibration. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at International Conference on Acoustics and Vibration (ICAV2016), which was organized b...

This study proposes a new mathematical mechanical model of a disc brake system that combines pad tangential motion and wobbling disk motion to reduce the vibration and noise of the brake system. The model presents two degrees of freedom. The stability analysis of this system is investigated by Lyapounov stability method. Then, the influence of angu...

Reducing vibrations of a powertrain system is an important research field addressed by many researchers. The study of the dynamic behavior of a powertrain system from the motor shaft to a brake depends on the analysis of sub-systems and specific principal components. The dynamic clutch and the stiffness variation of the meshing gears are two influe...

The study of acoustic radiation through a double laminated plates system requires the modelling of dynamic behaviour of laminated plates, joint, fluid cavity, external fluids and fluid structure interaction. A mixed method based on variational formulation for the fluid cavity and panels in terms of displacements for the structure and pressure for t...

This paper addresses the problem of determining the minimum clamping forces that ensure the dynamic fixturing stability. The clamping force optimization problem is formulated as a bi-level nonlinear programming prob- lem and solved using a computational intelligence technique called particle swarm optimization (PSO). Indeed, we present an innovativ...

Purpose – The purpose of this paper is to analyse the dynamic behaviour of an elasto‐plastic sandwich subjected to low velocity impact. Design/methodology/approach – A numerical model is developed with the assumption that the plastic deformation is confined under the contact area. The structure is analyzed using the in‐house finite element code wi...

In this paper, we present a three-dimensional manufacturing tolerancement model. Several researchers have interested to modelling the machining geometric defects. The most researchers are limited to kinematic and static study. Only some works are evoked the dynamic effects, especially the influence of the chatter phenomenon on the roughness of the...

The vibration response of sandwich panels, under low-velocity impact, is presented by using finite element method (FEM) and Hertz contact low. The vibrations on the sandwich plate under the impact are evaluated using the Wigner-Ville distribution. As a result, by formulating a simple model involving the motion of a rigid impactor combined with dyn...

Ce travail de recherche consiste à analyser l’influence de choix d’un tel montage de prise de pièce (type 3-2-1) sur le comportement vibratoire d’une pièce à usiner et par suite sur la stabilité de posage et fixation. Alors une étude paramétrique (emplacements des butées de mise en position, emplacements et nombre des brides de serrage, efforts de...

This paper presents a model-based framework for the verification of the dynamic stability of a fixtured workpiece during machining. The framework consists of a dynamic model for simulating the vibratory behaviour of the fixtured workpiece subjected to time- and spacevarying machining loads. We present a static model for determining the localized fi...

Sandwich structures have been broadly used in civil and aerospace engineering. The configuration of sandwich panels with two stiff face sheets and viscoelastic core provides high energy absorption capability. In this work we study the dynamic behaviour of sandwich plate in presence of shock. The shock is modelled by a contact between sandwich plate...

Free vibration and damping characteristics of a sandwich plate with elastic facings and visco-elastic core have been studied using a finite-element method. The present method considers a linear variation in the in-plane displacement through the thickness in the faces and a quadratic variation in the core. Quadrilateral finite elements were develope...

Numerical model has been developed to study the vibro-acoustic behaviour of a double sandwich panels system. This numerical model requires the modelling of dynamic behaviour of sandwich panels, air cavity and fluid structure interaction. In this paper, the associated energy functional formulation is established. Its discretization by finite element...