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Finite element analysis of slope stability by expanding the mobilized principal stress Mohr's circles-Development, encoding and validation

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第4期14卷 1165-1179页

作者： Djillali Amar bouzid Department of Civil Engineering Faculty of TechnologyUniversity of Blida 1Blida09000Algeria

In recent years,finite element analysis is increasingly being proposed in slope stability problems as a competitive method to traditional limit equilibrium methods(LEMs)which are known for their inherent ***,the application of finite element method(FEM)to slope stability as a strength reduction method(SRM)or as finite element limit analysis(FELA)is not always a success for the drawbacks that characterize both *** increase the performance of finite element analysis in this problem,a new approach is proposed in this *** consists in gradually expanding the mobilized stress Mohr’s circles until the soil failure occurs according to a prescribed non-convergence *** present approach called stress deviator increasing method(SDIM)is considered rigorous for three main ***,it preserves the definition of the factor of safety(FOS)as the ratio of soil shear strength to the mobilized shear ***,it maintains the progressive development of shear stress resulting from the increase in the principal stress deviator on the same plane,on which the shear strength takes ***,by introducing the concept of equivalent stress loading,the resulting trial stresses are checked against the violation of the actual yield criterion formed with the real strength parameters rather than those reduced by a trial *** new numerical procedure was encoded in a Fortran computer code called S^(4)DINA and verified by several *** with other numerical methods such as the SRM,gravity increasing method(GIM)or even FELA by assessing both the FOS and contours of equivalent plastic strains showed promising results.

关键词： Slope stability,Finite element analysis Strength reduction method(SRM),Stress point-based factor of safety(FOS),Limit equilibrium method(LEM),Stress deviator Mohr’s circle,Plastic strain

Energy based 3D trajectory tracking control of quadrotors with model-free based on-line disturbance compensation

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Chinese Journal of Aeronautics 2018年第7期31卷 1568-1578页

作者： Yasser bouzid Houria SIGUERDIDJANE Yasmina BESTAOUI IBISC Laboratory Université d'Evry Val d'Essonne Université Paris-Saclay L2S CentraleSupélecUniversité Paris-Saclay

In this work, a Revisited form of the so-called Model-Free Control（R-MFC） is ***, the MFC principle is employed to deal with the unknown part of a plant only（i.e., unmodeled dynamics, disturbances, etc.） and occurs beside an Interconnection and Damping AssignmentPassivity Based Control（IDA-PBC） strategy. Using the proposed formulation, it is shown that we can significantly improve the performance of the control through the reshaping properties of the IDA-PBC technique. Moreover, the control robustness level is increased via a compensation of the time-varying disturbances and the unmodeled system dynamics. This on-line compensation capability is provided by the MFC principle. The problem is studied in the case of Multi-Input Multi-Output（MIMO） mechanical systems with an explicit application to a small Vertical Take-Off and Landing（VTOL） Unmanned Aerial Vehicle（UAV） where a stability analysis is also provided. Numerical simulations have shown satisfactory results, in comparison with some other control strategies, where an in-depth discussion with respect to the control performance is highlighted by considering several scenarios and using several metrics.

关键词： IDA-PBC Model-free control Nonlinear flight control Robust control Trajectory tracking

Progressive collapse of 2D reinforced concrete structures under sudden column removal

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1387-1402页

作者： EI houcine MOURID Said MAMOURI Adnan IBRAHIMBEGOVIC Mechanics of Structures Laboratory MechanicsModeling and Experimentation Laboratory.Department of Mechanical EngineeringUniversity of Tahri Mohamed-Bechar Bechar 08000Algeria Roberal Mechanics laboratory Alliance Sorbonne UniversiyCompiegne 60203France

Once a column in building is removed due to gas explosion,vehicle impact,terrorist attack,earthquake or any natural disaster,the loading supported by removed column transfers to neighboring structural *** these elements are unable to resist the supplementary loading,they continue to fail,which leads to progressive collapse of *** this paper,an efficient strategy to model and simulate the progressive collapse of multi-story reinforced concrete structure under sudden column removal is *** strategy is subdivided into several connected steps including failure mechanism creation,MBS dynamic analysis and dynamic contact simulation,the latter is solved by using conserving/decaying scheme to handle the stiff nonlinear dynamic *** effect of gravity loads,structure-ground contact,and structure-structure contact are accounted for as *** main novelty in this study consists in the introduction of failure function,and the proper manner to control the mechanism creation of a frame until its total ***,this contribution pertains to a very thorough investigation of progressive collapse of the structure under sudden column *** proposed methodology is applied to a six-story frame,and many different progressive collapse scenarios are *** results ilustrate the efficiency of the proposed strategy.

关键词： failure mechanism MBS dynamic analysis gravity loads structure-ground contact structure-structure contact energy conserving decaying scheme

Assessment of some chemical element contents in Traganum nudatum Del shrub using instrumental neutron activation analysis

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Nuclear Science and Techniques 2015年第4期26卷 46-50页

作者： bouzid Nedjimi Brahim Beladel Laboratory of Exploration and Valuation of the Steppe Ecosystem Faculty of Science of Nature and Life University of Djelfa University of Djelfa

Instrumental neutron activation analysis(INAA)has been used to determine some chemical element contents(K,Ca,Na,Fe,Zn,Co,Eu,Sb,and Sc)in Traganum nudatum Del(Chenopodiaceae family)consumed in North African rangelands by sheep *** were collected from the area of Djelfa in an arid steppe of *** show that pasture halophyte had sufficient levels of K,Ca,Zn,and Co to meet the requirements of ***,it seems that this halophyte shrub had substantial amounts of Na,higher than the critical level established by the National Research Council(NRC).Eu,Sb,and Sc were within the safety baseline of all the assayed elements recommended by the *** high Na content(～10 g/kg)in this halophytic species requires elevated intake of water by livestock.

关键词：仪器中子活化分析化学元素含量灌木评价盐生植物阿尔及利亚钙水平 INAA

Effect of seasonal changes on predictive model of bovine babesiosis transmission

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International Journal of Modeling, Simulation, and Scientific Computing 2017年第3期8卷 178-194页

作者： Leila bouzid Omar Belhamiti Laboratory of Pure and Applied Mathematics Department of Mathematics and Computer Science Abdelhamid Ben Badis University Mostaganem 27000 Algeria

In this paper,we present an attempt at analyzing the seasonal pattern of the Babesiosis transmission dynamics in bovine and tick *** infestation rate plays an important role in the variation of *** this logic,we set out a mathematical model with variable infestation rate for the evolution of babesiosis *** the(0,2)-Jacobi multi-wavelets method combined with the decoupling and quasi-linearization technique,we demonstrate the validity and applicability of our ***,a set of experimental data is used to validate the proposed model under the same operating *** results of numerical simulations are provided to show the impact of seasonality on the transmission dynamics of ***,a numerical study of the model varying the control parameters of babesiosis shows different scenarios about the spread of the disease.

关键词： Babesiosis disease seasonal effects infestation rate jacobi wavelets method

Assessment of natural frequency of installed offshore wind turbines using nonlinear finite element model considering soil-monopile interaction

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第2期10卷 333-346页

作者： Djillali Amar bouzid Subhamoy Bhattacharya Lalahoum Otsmane Department of Civil Engineering Faculty of Technology University Saad Dahled of Blida Department of Civil and Environmental Engineering Tomas Telford Building University of Surrey Department of Material Engineering Faculty of Sciences and TechnologyUniversity of Médéa

A nonlinear finite element model is developed to examine the lateral behaviors of monopiles, which support offshore wind turbines(OWTs) chosen from five different offshore wind farms in Europe. The simulation is using this model to accurately estimate the natural frequency of these slender structures, as a function of the interaction of the foundations with the subsoil. After a brief introduction to the wind power energy as a reliable alternative in comparison to fossil fuel, the paper focuses on concept of natural frequency as a primary indicator in designing the foundations of OWTs. Then the range of natural frequencies is provided for a safe design purpose. Next, an analytical expression of an OWT natural frequency is presented as a function of soil-monopile interaction through monopile head springs characterized by lateral stiffness KL, rotational stiffness KRand cross-coupling stiffness KLRof which the differences are discussed. The nonlinear pseudo three-dimensional finite element vertical slices model has been used to analyze the lateral behaviors of monopiles supporting the OWTs of different wind farm sites considered. Through the monopiles head movements(displacements and rotations), the values of KL, KRand KLRwere obtained and substituted in the analytical expression of natural frequency for comparison. The comparison results between computed and measured natural frequencies showed an excellent agreement for most cases. This confirms the convenience of the finite element model used for the accurate estimation of the monopile head stiffness.

关键词： Nonlinear finite element analysis Vertical slices model Monopiles under horizontal loading Natural frequency Monopile head stiffness Offshore wind turbines(OWTs)

Mechanical and Metallurgical Characterization of HSLA X70Welded Pipeline Steel Subjected to Successive Repairs

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Acta Metallurgica Sinica(English Letters) 2016年第6期29卷 568-576页

作者： bouzid Maamache Mabrouk Bouabdallah Abdelhalim Brahimi Youcef Yahmi Billel Cheniti Brahim Mehdi Research Center in Industrial Technologies(CRTI) P.O.Box 6416014 CheragaAlgeria Laboratoire des Aeronefs Universite de Blidal09000 BlidaAlgeria LGSDS Ecole Nationale PolytechniqueEl Harrach16200AlgiersAlgeria LTSM Universite de Blidal09000 BlidaAlgeria ICMMO/SP2M Bat 410Universite Paris-Sud 1191405Orsay CedexFrance

The aim of this work is to study the influence of successive weld repairs on the microstructure and the mechanical behavior of the heat-affected zone（HAZ） of an HSLA X70 steel. Detailed microstructural examination combined to grain size measurement showed that beyond the second weld repair, the microstructure of the HAZ undergoes significant change in the grain morphology and grain growth. The results of the X-ray diffraction analyzed using MAUD software indicated an increase in the crystallite size and a decrease in the dislocation density according to the number of weld repair operations. Consequently, a loss of mechanical properties, namely the yield strength and the toughness with the number of weld repairs, was recorded. Beyond the second weld repair operation, the properties of the welded joint do not fulfill the standards applied in piping industry.

关键词： HSLA X70 steel Successive weld repair Heat affected zone Dislocation density

Insight of ZnS nanoparticles contribution in different biological uses

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Asian Pacific Journal of Tropical Medicine 2016年第8期9卷 735-740页

作者： houcine Labiadh Karima Lahbib Slah Hidouri Soufiane Touil Tahar BEN Chaabane Unité de Recherche UR11ES30 de Synthèse et Structures de Nanomatériaux Faculté des Sciences de Bizerte Laboratory of Heteroatom organic chemistry Department of Chemistry Faculty of Sciences of Bizerte 7021 Jarzouna Carthage University Department of Research in Sciences of Life and Materials Faculty of Sciences of Bizerte Carthage University

Objective:To evaluate the contributions of the some quantum dots in different biological uses in order to valorizes such nanomaterials for further ***:Zinc sulfide ZnS nanoparticles were synthesized in aqueous medium at pH constant,the obtained nanoparticles has been characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM)and Fourier Transform Infra-red(FTIR) *** sulfide nanoparticles were screened for their antibacterial and antifungal profiling and tested for antioxidant activity using l,l-diphenyl-2-picrylhydrazyl(DPPH),hydroxyl radical(OH·) and hydrogen peroxide(H_2O_2) scavenging activity,ferric reducing power(FRP) assay and ferrous ion chelating(FIC)***:The sizes of the crystallites were estimated to 3 nm using the DebyeScherrer formula based on the XRD *** shape was identified to be quasi-spherical whith agglomerated *** obtained ZnS quantum dots present an antioxidant activity especially in oxido-reduction power,and can be used for species profiling either for bacteria and ***:It was found that ZnS nanoparticles showed relatively higher antioxidant activities and antibacterial with an antifungal behavior which proves that this nanomaterials can react at the interface with the life entities.

关键词： Nanoparticles Semiconductors Antioxidant activity Antibacterial activity Antifungal activity

Aggressiveness Assessment of Two Fusarium spp. on Durum Wheat Grain Coleoptiles under Controlled Conditions

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Phyton-International Journal of Experimental Botany 2024年第11期93卷 2983-2992页

作者： Salah Hadjout Mohamed Zouidi houcine Bougrine Abdeldjalil Belkendil Amer Zeghmar Walid Ouaret Walid Soufan Fathi Abdellatif Belhouadjeb Centre de Recherche en Amenagement du Territoire(CRAT) Campus Zouaghi SlimaneRoute de Ain el BeyConstantine25000Algerie Ecole Nationale Superieure Agronomique(ENSA) Alger16200Algerie Department of Geographical Sciences University of MarylandCollege ParkMD 20742USA Plant Production Department College of Food and Agriculture SciencesKing Saud UniversityRiyadh11451Saudi Arabia Centre de Recherche en Agropastoralisme(CRAPast) Djelfa17000Algerie

Fusarium head blight(FHB)is a disease caused by several Fusarium species,notably,*** and *** pathogens adversely affect the technological and sanitary qualities of cereal grains,particularly durum *** favorable environmental conditions and in susceptible varieties,these Fusarium species can signiﬁcantly reduce both the quantity and quality of *** study evaluated the pathogenicity of the two Fusarium species(FC2006 and FG2008)in the growth of durum wheat *** plant material included four commercially grown parental varieties(G9,G10,G11,G12)and eight breeding lines(G1,G2,G3,G4,G5,G6,G7,G8).In vitro tests revealed that both Fusarium species signiﬁcantly reduced the coleoptile growth across the studied varieties and lines(p≤0.001).The control test had an average coleoptile length of 37.87 *** contrast,seeds inoculated with FC2006 had an average length of 0.62 mm,and those inoculated with FG2008 had only 0.064 *** there was a slight difference in aggressiveness between the two spe-cies,it was not statistically signiﬁcant(p>0.05).Some variability was also noted in the responses of the durum wheat varieties and *** G8 genotype showed remarkable behavior in both isolates,with an average length of 1.83 mm for FC2006 and 0.4 mm for *** other genotypes showed total inhibition of coleoptile growth(0 mm).Theseﬁndings highlight the importance of conducting further research on the defense mechanisms of durum wheat against Fusarium and assessing the local varieties’pathogenicity to better explore the interactions between these pathogens and durum wheat genotypes under in vitro conditions.

关键词： Fusarium species aggressiveness coleoptile growth durum wheat in vitro test