Filters








6 Hits in 1.3 sec

Reduction Method Applied to Viscoelastically Damped Finite Element Models [chapter]

Souhir Zghal, Mohamed Lamjed Bouazizi, Rchid Nasri, Noureddine Bouhaddi
2013 Lecture Notes in Mechanical Engineering  
We propose in this paper to combine the GHM (Golla-Hughes-Mc Tavish) method with model reduction technique, especially direct condensation methods to resolve the problem of increased model order of viscoelastically structures. In fact, modeling structures using the GHM method leads to global systems of equation of motion whose numbers of degrees-offreedom largely exceeds the order of the associated undamped system. As result, the numerical resolution of such equations can require prohibitive
more » ... putational (CPU) time. So, to overcome this problem, both Static and Dynamic methods are used to reduce the order of finite elements matrices while preserving its capability to represent the dynamic behavior of viscoelastically damped structures. This paper intends to compare these two methods in direct reduction. Numerical example applied to cantilever beam structure is presented. This example will highlight the domain of validity of the studied methods. Results obtained from these two reduction methods are compared with the full model in order to illustrate its performances and its practical interest in the dynamic analysis of viscoelastically damped structures.
doi:10.1007/978-3-642-37143-1_15 fatcat:3pdz6naapnfina4ngozsiklzhy

Dynamics of convective slippery constraints on hybrid radiative Sutterby nanofluid flow by Galerkin finite element simulation

Jamel Bouslimi, Ali A. Alkathiri, Abdulaziz N. Alharbi, Wasim Jamshed, Mohamed R. Eid, Mohamed Lamjed Bouazizi
2022 Nanotechnology Reviews  
The heat transport and entropy formation of an unsteady Sutterby hybrid nanofluid (SBHNF) are investigated in this work. SBHNF's flowing and thermal transport properties are investigated by exposing the nanofluid to a slippery hot surface. This analysis includes the influences of solid-shaped nanoparticles, porous materials, radiative flux, and viscous dissipative flow. The Galerkin finite element technique (G-FEM) is used to find self-similar solutions to equations that are then transformed
more » ... o ODEs using appropriate transformations. This research considers two diverse kinds of nanosolid-particles, copper (Cu) and graphene oxide (GO), using non-Newtonian engine-oil (EO) as the working fluid. In the flowing, energy, skin friction, Nusselt number, and entropy production, important findings for the various variables are visually depicted. The most notable finding of the analysis is that when SBHNF (GO–Cu/EO) is compared to a typical nanofluid (Cu–EO), the thermal transmission rate of SBHNF (GO–Cu/EO) gradually increases. Furthermore, heat transfer is greatest for spherical-shaped nanoparticles and lowest for lamina-shaped nanoparticles. The entropy in the model is increased when the size of the nanoparticles ϕ \phi is increased. The comparable impact is noticed once the radiation flowing N r {N}_{\text{r}} and Deborah number λ \lambda increase.
doi:10.1515/ntrev-2022-0070 fatcat:mwi4u5aatjez5ccm6kvs5wjnue

Model reduction methods for viscoelastic sandwich structures in frequency and time domains

Souhir Zghal, Mohamed Lamjed Bouazizi, Noureddine Bouhaddi, Rachid Nasri
2015 Finite elements in analysis and design  
doi:10.1016/j.finel.2014.08.003 fatcat:y7idbq4l2bdrrhmxpbpueydfm4

Generation of Reference Softgauges for Minimum Zone Fitting Algorithms: Case of Aspherical and Freeform Surfaces

Amine Chiboub, Yassir Arezki, Alain Vissiere, Charyar Mehdi-Souzani, Nabil Anwer, Bandar Alzahrani, Mohamed Lamjed Bouazizi, Hichem Nouira
2021 Nanomaterials  
Optical aspherical lenses with high surface quality are increasingly demanded in several applications in medicine, synchrotron, vision, etc. To reach the requested surface quality, most advanced manufacturing processes are used in closed chain with high precision measurement machines. The measured data are analysed with least squares (LS or L2-norm) or minimum zone (MZ) fitting (also Chebyshev fitting or L∞-norm) algorithms to extract the form error. Performing data fitting according to L∞-norm
more » ... is more accurate and challenging than L2-norm, since it directly minimizes peak-to-valley (PV). In parallel, reference softgauges are used to assess the performance of the implemented MZ fitting algorithms, according to the F1 algorithm measurement standard, to guarantee their traceability, accuracy and robustness. Reference softgauges usually incorporate multiple parameters related to manufacturing processes, measurement errors, points distribution, etc., to be as close as possible to the real measured data. In this paper, a unique robust approach based on a non-vertex solution is mathematically formulated and implemented for generating reference softgauges for complex shapes. Afterwards, two implemented MZ fitting algorithms (HTR and EPF) were successfully tested on a number of generated reference pairs. The evaluation of their performance was carried out through two metrics: degree of difficulty and performance measure.
doi:10.3390/nano11123386 pmid:34947735 pmcid:PMC8703870 fatcat:uw7w2spejvfxhfhdybod3e2xrm

Traceable Reference Full Metrology Chain for Innovative Aspheric and Freeform Optical Surfaces Accurate at the Nanometer Level

Yassir Arezki, Rong Su, Ville Heikkinen, François Leprete, Pavel Posta, Youichi Bitou, Christian Schober, Charyar Mehdi-Souzani, Bandar Abdulrahman Mohammed Alzahrani, Xiangchao Zhang, Yohan Kondo, Christof Pruss (+5 others)
2021 Sensors  
The design of innovative reference aspheric and freeform optical elements was investigated with the aim of calibration and verification of ultra-high accurate measurement systems. The verification is dedicated to form error analysis of aspherical and freeform optical surfaces based on minimum zone fitting. Two thermo-invariant material measures were designed, manufactured using a magnetorheological finishing process and selected for the evaluation of a number of ultra-high-precision measurement
more » ... machines. All collected data sets were analysed using the implemented robust reference minimum zone (Hybrid Trust Region) fitting algorithm to extract the values of form error. Agreement among the results of several partners was observed, which demonstrates the establishment of a traceable reference full metrology chain for aspherical and freeform optical surfaces with small amplitudes.
doi:10.3390/s21041103 pmid:33562598 pmcid:PMC7915810 fatcat:tjmu7gk65zdfrfe2mq6e4yueoe

REPUBLIQUE TUNISIENNE MINISTERE DE L'ENSEIGNENMENT SUPERIEUR ET DE LA RECHERCHE SCIENTIFIQUE Mémoire Pour l'obtention d'un Diplôme de Mastère Professionnel Réalisé par Mohamed Mehdi MAMLOUK Business Plan pour la création d'une Agence maritime de Consignation de navire

Université Virtuelle De Tunis, Mr Taktak, El Hassen
unpublished
Neziha Nsiri épouse Bouazizi Khelil Hafhouf Mohamed Fethi Beji Fadhel Dhouha Mabrouka Ghannoudi épouse Grab Mohamed Ben Rejab Khaled Bargou Mohamed Cherif Jelidi N° 59 Journal Officiel de  ...  Hédi Dachraoui Mohamed Lamjed Cherif Nejia Melki épouse Ben Arbi Sassia Shili épouse Abdelkerim Chedila Belkahla épouse Azouz Zakia Ben Abderazek épouse Kacem Noureddine Ferchichi Mongi Ksara  ... 
fatcat:s3axp24uxjbinjcasskgjbyt2i