El Jadida, Morocco
El Jadida, Morocco

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Cherif A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Cherif A.,Ferhat Abbas University Setif | Richard C.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Guyomar D.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | And 8 more authors.
Nonlinear Optics Quantum Optics | Year: 2015

Advanced materials such as carbon fiber, composite materials et al. are more and more used in modern industry. They make the structures lighter and stiffer. However, they bring vibration problems. Researchers studied numerous methods to eliminate the undesirable vibrations. These treatments are expected to be a compact, light, intellectual and modular system. Recently, nonlinear techniques which are known as Synchronized Switch Damping (SSD) technique was proposed. These techniques synchronously switched when structure got to its displacement extremes that leading to a nonlinear voltage on the piezoelectric elements. This paper presents a performance analysis of an improved modal SSDI approach called "SSDI Max". The particularity of this new approach is to maximize the self generated voltage amplitude by a proper definition of the switch instants according to the chosen targeted mode. This paper presents simulations performed on a model representative of a smart beam. Damping results are given in the case of multimodal excitations. The paper analyses the control time window influence on the damping performance of the system. Results show that substantial damping increase can be obtained with very slight modification of the control architecture and the same control energy. © 2015 Old City Publishing, Inc.


Sahraoui B.,University of Angers | Karakas A.,Selcuk University | Hajjaji A.,University dEl Jadida | Kouari Y.E.,Hassan II University | Migalska-Zalas A.,J Dlugosz Academy Of Czestochowa
International Conference on Transparent Optical Networks | Year: 2012

Nonlinear optical (NLO) materials have been extensively studied for many years. The search of new materials with NLO properties is an important research field. Significant interest still exists in the design and development of materials exhibiting large second and third-order NLO response because of the potential application in optoelectronics devices [1-2]. In this talk, comparison between quantum mechanical computations of NLO properties and experimental data in selected azo-dyes will be done. Particularly we will focus on correlation between macroscopic level and microscipic one. To reveal the microscopic second-order NLO properties of a family of azo-azulenes, the electric dipole moments (μ) and static first hyperpolarizabilities () have been evaluated by using density functional theory (DFT) quantum mechanical calculations at B3LYP/ 6-311G (d, p) level. The calculation results with non-zero values on first hyperpolarizabilities indicate that the title molecules might possess microscopic second-order NLO phenomena. The maximum one-photon absorption (OPA) wavelengths obtained by theoretical computations using the configuration interaction (CI) method are located in the visible region, supporting the π → π transitions. We have also calculated the dynamic second (χ 2) and third-order (χ 3+) susceptibilities using the time-dependent Hartree-Fock (TDHF) method. © 2012 IEEE.


Eddiai A.,CNRS Condensed Matter Physics Laboratory | Eddiai A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,Ferhat Abbas University Setif | And 6 more authors.
Synthetic Metals | Year: 2012

The purpose of this paper is to propose new means for harvesting energy using electrostrictive polymers. The recent development of electrostrictive polymers has generated new opportunities for high-strain actuators. At the current time, the investigation of using electrostrictive polymer for energy harvesting, or mechanical-to-electrical energy conversion, is beginning to show its potential for this application. The objective of this work was to study the effect of cellular polypropylene electrets after high-voltage corona poling on an electrostrictive polyurethane composite filled with 1 vol.% carbon black at a low applied voltage in order to increase the efficiency of the electromechanical conversion with electrostrictive polymers. Theoretical analysis supported by experimental investigations showed that an energy harvesting with this structure rendered it possible to obtain harvested power up to 13.93 nW using a low electric field of 0.4 V/μm and a transverse strain of 3% at a mechanical frequency of 15 Hz. This represents an efficiency of 78.14% at low frequency. This percentage is very significant compared to other structures. Finally, it was found that the use of polypropylene electrets with electrostrictive polymers was the best way to decrease the power of polarization in order to obtain a good efficiency of the electromechanical conversion for energy harvesting. © 2012 Elsevier B.V.


Eddiai A.,CNRS Condensed Matter Physics Laboratory | Eddiai A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,Ferhat Abbas University Setif | And 4 more authors.
International Conference on Transparent Optical Networks | Year: 2012

Recent trends in energy conversion mechanisms have demonstrated the abilities of electrostrictive polymers for converting mechanical vibrations into electricity. In particular, such materials present advantageous features such as a high productivity, high flexibility, and ease of processing; hence, the application of these materials for energy harvesting purposes has been of significant interest over the last few years. The purpose of this paper is to propose the mechanical effect on the performance of electrostrictive polymers for energy harvesting. when the sample simultaneously driven by an electrical field and a mechanical excitation. Experimental measurements of the harvested power has been compared with the theoretical behavior predicted by the proposed model. A good agreement was observed between the experimental and the theoretical results. Finally, the results indicated that the strain was the crucial parameter for a good efficiency of the electromechanical conversion with electrostrictive polymers. © 2012 IEEE.


Meddad M.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,Ferhat Abbas University Setif | Eddiai A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Eddiai A.,CNRS Condensed Matter Physics Laboratory | And 6 more authors.
Optical Materials | Year: 2013

Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations. © 2013 Elsevier B.V. All rights reserved.


Meddad M.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Meddad M.,Ferhat Abbas University Setif | Eddiai A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Eddiai A.,CNRS Condensed Matter Physics Laboratory | And 6 more authors.
Journal of Applied Physics | Year: 2012

The harvesting energy with electrostrictive polymers has great potential for remote applications such as invivo sensors, embedded micro-electro- mechanical systems devices, and distributed network instruments. A majority of current research activities in this field refers to classical piezoelectric ceramics, but electrostrictive polymers offer promise of energy harvesting with few moving parts; power can be produced by simply stretching and contracting a relatively low-cost rubbery material. The use of such polymers for energy harvesting is a growing field, which has great potential from an energy density viewpoint. The output power is inversely proportional to the harvesters frequency bandwidth. Consequently, it is much harder to efficiently harvest power from low-frequency sources with a large frequency band response and with a very small system size than from a stabilized high-frequency vibration source. This paper presents a new structure that is able to predict mechanical frequency excitation in order to increase power-harvesting capabilities of electrostrictive polymers. An equivalent structure scheme has been developed by using current and electrical schemes models. With a transverse strain of 0.5% and a bias field of 10 V/μm, such a process rendered it possible to increase the converted power by 80% with a low-frequency mechanical excitation. This study contributes to provide a framework for developing an innovative energy-harvesting technology that collects vibrations from the environment and converts them into electricity to power a variety of sensors. © 2012 American Institute of Physics.


Cherif A.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Cherif A.,Ferhat Abbas University Setif | Richard C.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | Guyomar D.,CNRS Laboratory of Electrical Engineering and Ferroelectricity | And 6 more authors.
Journal of Optoelectronics and Advanced Materials | Year: 2013

Semi-active control is based on modal control strategy that needs very some energy for work but is effective only when the excitation is targeted on a unique mode. To improve the performance of semi-active control in the case of a broadband excitation, a modal approach SSDI-Max is proposed. This present paper presents an analysis of the performance of the SSDI-Max damping technique with a Beam-structure. It relies on simulations, made with the Matlab-Simulink environment, using a realistic model of a beam structure previously identified. The proposed method aims at maximizing the amplitude of the piezoelectric actuator by the definition of an optimal switching time according to the targeted mode chosen. Starting at this time, an algorithm is implemented to wait for the next voltage extremum within a given time window. The performances of the SSDI-Max method for the control of single mode of the structure are described in the case of pulse and noise excitations. Finally the influence of the delay time window used is described again for pulse and noise excitations for various modes.

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