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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

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)

Graphene platform for neural regenerative medicine

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Neural Regeneration Research 2016年第6期11卷 894-895页

作者： Tasneem bouzid Alexander Sinitskii Jung Yul Lim Department of Mechanical and Materials Engineering University of Nebraska-Lincoln Department of Chemistry University of Nebraska-Lincoln Graduate School of Dentistry Kyung Hee University

Graphene is a material composed of a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice. The unique elec- trical, optical, thermal, and mechanical properties of graphene are extensively explo... 详细信息

关键词： Graphene platform for neural regenerative medicine NFL cell FAK RA

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

Erbium Doped Fiber Laser and Amplifier

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Optics and Photonics Journal 2014年第7期4卷 189-193页

作者： Belloui bouzid Electrical Engineering Department Affiliated Colleges Hafr Al-Batin King Fahd University of Petroleum and Minerals (KFUPM) Riyadh KSA

In this paper, new configuration is proposed, investigated and analyzed. Fiber laser and fiber amplifier are merged in one configuration which called Erbium Doped Fiber Laser and Amplifier (EDFLA) or integrating EDFL and EDFA in one design. The configuration has three main outputs;one for laser, second for amplifier and the third it can be used for on/off output. A surprising phenomenon was remarked during the operation of this configuration. The amplification is abolished during the lasing state and appeared again if the lasing is stopped or the switch is off. The difference between outputs with the lasing and without lasing has 30 dB EDFA gain value;it is a good sign that this optical configuration can be used as an on/off integrated optical device for fiber laser.

关键词： Erbium Doped Fiber Amplifier Erbium Doped Fiber Laser Lasing Amplification

Failure Analysis of an Aluminum Extension Portable Ladder

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Materials Sciences and Applications 2014年第9期5卷 674-684页

作者： Abdel-Hakim bouzid Department of Mechanical Engineering école de Technologie Supérieure Montreal Cananda

The conditions of end supports of straight ladders are often the cause of major injuries. The firm and secure ladder ends against instability in general and sliding of the top and bottom ends in particular are among the check list of most ladder safety training books and manuals. However, the restraint to the free expansion of a ladder can cause a catastrophic failure due to buckling even at intermediate loads and should be presented in the latter as a serious potential hazard. This paper deals with an investigation of an extension. An analytical structural model that simulates the buckling behavior of an axially restrained ladder subjected to static and dynamic loading is developed. It compares two different ladder end conditions and shows that instability due to buckling can occur during ascension or descent in the case of an axially restrained ladder. The analytical results are supported and validated by a finite element model simulation conducted in parallel. This study may explain the root cause of similar incidents involving falls from portable ladders worldwide.

关键词： Portable Ladder Beam Shortening Columns Axially Restrained Buckling