On the mixed-mode crack propagation in FGMs plates: comparison of different criteria

Benamara Nabil,Boulenouar Abdelkader,Aminallah Miloud,Benseddiq Noureddine 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.3

Modelling of a crack propagating through a finite element mesh under mixed mode conditions is of prime importance in fracture mechanics. In this paper, two crack growth criteria and the respective crack paths prediction in functionally graded materials (FGM) are compared. The maximum tangential stress criterion (et -criterion) and the minimum strain energy density criterion (S-criterion) are investigated using advanced finite element technique. Using Ansys Parametric Design Language (APDL), the variation continues in the material properties are incorporated into the model by specifying the material parameters at the centroid of each finite element. In this paper, the displacement extrapolation technique (DET) proposed for homogeneous materials is modified and investigated, to obtain the stress intensity factors (SIFs) at crack-tip in FGMs. Several examples are modeled to evaluate the accuracy and effectiveness of the combined procedure. The effect of the defects on the crack propagation in FGMs was highlighted.

Durability of high performance sandcretes (HPS) in aggressive environment

Benamara, Dalila,Tebbal, Nadia,Rahmouni, Zine El Abidine Techno-Press 2019 Advances in concrete construction Vol.8 No.3

High performance sandcretes (HPS) are new concretes characterized by particles having a diameter less than 5 mm, as well as very high mechanical strength and durability. This work consists in finding solutions to make sandcretes with good physico-mechanical and durability properties for this new generation of micro-concrete. However, upgrading ordinary sandcrete into high performance sandcrete (HPS) requires a thorough study of formulation parameters (equivalent water/binder ratio, type of cement and its dosage, kind and amount of super plasticizer, and gravel/sand ratio). This research study concerns the formulation, characterization and durability, in a sulphate environment, of a high performance sandcrete (HPS), made from local materials. The obtained results show that the rheological properties of fresh concrete and mechanical strength differ with the mineralogy, density and grain size distribution of sands and silica fume used.

Algerian extra hard cheese of Klila: a review on the production method, and microbial, organoleptic, and nutritional properties

Benamara Rym Nouria,Benahmed Meryem,Ibri Kada,Moussa Boudjemaa Boumediene,Demarigny Yann 한국식품연구원 2022 Journal of Ethnic Foods Vol.9 No.-

This paper reviews the traditional practice of Klila production, its microbiological, physicochemical and nutritional properties and aims to raise awareness of Klila. The main objective of this review is to highlight the typicality of Klila and to propose a form of labelling that could help promote it. The Klila is a traditional extra hard cheese from southern Algeria. Nomadic tribes produce it from goat, sheep, or cow milk. Curdled milk is obtained by spontaneous fermentation. It is churned to recover the butter. The co-product, a sour, fat-free milk: Lben, undergoes a moderate heat treatment to get a fresh cheese which, after a dehydration process, gives the Klila. The chemical composition of this product varies regarding fat content. It has a very low water content (less than 10%) and comes in very hard pieces of varying size and irregular shape. The dry matter, for instance, can vary from 33 to 95%. Water availability (Aw) varies from 0.32 to 0.467. Fat rate can vary a lot from region to region from 9.5 to 29.3 g/100 g of cheese. The protein rate also varies a lot: between 29.9 and 71.4 g/100 g of cheese. The lactose concentration can range within 1.2 to 2.4 g/100 mL. The microbiological quality of Klila depends mainly on the quality of the raw milk used and all hygienic factors that surround milk production. The physicochemical conditions that prevail inside Klila are not favourable for the microbial growth. The Klila is an example of adaptation of the nomads’ lifestyle in the Algerian Sahara who use it as a culinary adjunct for nutritional and therapeutic purposes. The Klila can be grinded to be put as ingredient in “Zrizri” dessert with dates and clarified butter (smen). Some people prefer to consume fresh Klila with dates and green tea.

Contribution of Geophysics to the Study of Barite Mineralization in the Paleozoic Formations of Asdaf Tinejdad (Eastern Anti Atlas Morocco)

Dakir Ibrahim,Benamara Ahmed,Aassoumi Habiba,Ouallali Abdessalam,Ait Bahammou Youssef 대한자원환경지질학회 2020 자원환경지질 Vol.53 No.3

The use of the geophysical method in mining prospecting has been studied in the Asdaf region (South-East of Morocco). The objective of the study is to examine the aptitude of the electrical technique, in this case induced polarization (IP) and electric tomography, combined with the electromagnetic method (VLF), in the exploration of barite . The result obtained by the pseudo-sections of electrical tomography and that of KH filtration highlighted anomalies of resistant contact (greater than 400Ω.m) and of high charge chargeability (5mV / V). These contacts are hosted in less resistant Devonian age shale and sandstone. The resistivity response obtained at their level is characteristic of the venous structures associated with barite mineralization. The direction of the mineralized veins is parallel to the direction of the fractured zones (NE-SW), which indicates that the mineralization in place is due to the tectonic movements of the Hercynian orogeny (from Devonian to Permian). These veins are aligned with the locations of abandoned mine shafts and with surface mining areas. Geophysical technique therefore seems to play a key role in barite mining exploration.

CAD model simplification using a removing details and merging faces technique for a FEM simulation

Hamdi Mounir,Aifaoui Nizar,Benamara Abdelmajid 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

The simulation process is currently used in the design and dimensioning of mechanical parts. With the progress of computer materials,the finite elements method (FEM) becomes the most used approach in the simulation of mechanical behaviour. The simulation process needs multiple Design-FEM loops. In order to accelerate those analysis loops, an adaptation of computer aided design (CAD) model is necessary. The adaptation step consists in the simplification of the CAD model geometry by eliminating details (holes, chamfers, fillet,etc.) and faces. In this paper, a novel technique of simplification of the CAD geometry is developed. This technique is a hybrid method based on a combination of the elimination details and merging faces. The merging of faces is based on the energetic method. With this approach, the computing time is reduced by the elimination of geometric details which do not boundary conditions. An implementation of the proposed algorithm on the Open Cascade platform is also presented. The results of the developed method are compared with a previous publication. The reduction of the computing time and the amelioration of the result precision highlight the efficiency of the presented method.

Effect of cavity-defects interaction on the mechanical behavior of the bone cement

Zouambi, Leila,Serier, Boualem,Benamara, Nabil Techno-Press 2014 Advances in materials research Vol.3 No.1

The presence of cavities in the bone cement has a great importance for the transport of antibiotics, but its existence in this material can lead to its weakening by notch effect. The aim of this study allows providing a physical interpretation to the cavities interconnection by cracks observed experimentally. The most important stress of Von Mises is localized at the cement/bone interface near the free edge which is the seat of stress concentration. The presence and interaction of cavities in this site concentrate, by notch effect, stresses which tend to the tensile fracture stress of Bone cement.

An Optimization-based Computational Method for Surface Fitting to Update the Geometric Information of An Existing B-Rep CAD Model

Louhichi, Borhen,Aifaoui, Nizar,Hamdi, Mounir,BenAmara, Abdelmajid,Francois, Vincent Society for Computational Design and Engineering 2009 International Journal of CAD/CAM Vol.9 No.1

For several years, researchers have focused on improving the integration of the CAD, CAM and Analysis through a better communication between the various analysis tools. This tendency to integrate the CAD/Analysis and automation of the corresponding processes requires data sharing between the various tasks using an integrated product model. We are interested in this research orientation to CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results (deformed mesh). Because this problem is complex, it requires to be split into several complementary parts. This paper presents an original interoperability process between the CAD and CAE. This approach is based on a new technique of rebuilding the CAD surface model (Nurbs, Bezier, etc.) starting from triangulation (meshed surface) as a main step of the BREP solid model. In our work, the advantages of this approach are identified using a centrifugal pump example.

A New Eco-Design Approach on CAD Systems

Raoudha Gaha,Bernard Yannou,Abdelmajid Benamara 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Today it becomes necessary for manufacturers to adopt Eco-design to guard their place in the market. Eco-designing products, isreducing their environmental impact in the early design stages throughout all stages of their life cycle (raw material extraction,manufacturing process, use, transport and end of life treatments). In the literature, many tools and methodologies were developed tosimplify the environmental task to the designer by helping him reduce the environmental impact of his products. The most of theseworks are based in feature-based modeling to extract data for realizing environmental evaluation (EE) also we found that thistechnology is essentially used in selecting a green machining process through Computer Aided Process Planning (CAPP). In this paperwe propose a methodology based on feature technology and on the integrations realized on CAD systems such as CAD/CAM/CAPPand CAD/PLM to generate alternative scenarios in order to choose the most ecological one till feature’s selection. The environmentalimpact is calculated with CML method and shown to the designer as End-Points Indicators (Resources, Human Health, Eco-systemdamages) which are related to the designer’s Degrees of Freedom (DoFs). A case study was considered to valid our proposed approachand results are shown and compared to results obtained from SW sustainability and a complete LCA from SimaPro integrations.

State filling dependent luminescence in hybrid tunnel coupled dot-well structures.

Mazur, Yuriy I,Dorogan, Vitaliy G,Ware, Morgan E,Marega, Euclydes,Benamara, Mourad,Zhuchenko, Zoryana Ya,Tarasov, Georgiy G,Lienau, Christoph,Salamo, Gregory J RSC Pub 2012 Nanoscale Vol.4 No.23

<P>A strong dependence of quantum dot (QD)-quantum well (QW) tunnel coupling on the energy band alignment is established in hybrid InAs/GaAs-In(x)Ga(1-x)As/GaAs dot-well structures by changing the QW composition to shift the QW energy through the QD wetting layer (WL) energy. Due to this coupling a rapid carrier transfer from the QW to the QD excited states takes place. As a result, the QW photoluminescence (PL) completely quenches at low excitation intensities. The threshold intensities for the appearance of the QW PL strongly depend on the relative position of the QW excitonic energy with respect to the WL ground state and the QD ground state energies. These intensities decrease by orders of magnitude as the energy of the QW increases to approach that of the WL due to the increased efficiency for carrier tunneling into the WL states as compared to the less dense QD states below the QW energy.</P>

Critical size of self-propelled motion of droplets on GaAs (100) surface

Wu, Jiang,Wang, Zhiming M.,Li, Alvason Z.,Benamara, Mourad,Lee, Jihoon,Koukourinkova, Sabina D.,Soo Kim, Eun,Salamo, Gregory J. American Institute of Physics 2012 JOURNAL OF APPLIED PHYSICS - Vol.112 No.4