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Lateral ring compression test applied to a small caliber steel jacket:Identification of a constitutive model

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defence Technology（防务技术） 2024年第6期36卷 133-148页

作者： Yann Coget Yael demarty Christophe Czarnota Anthony Bracq Jean-Sebastien Brest Alexis Rusinek French-German Research Institute of Saint-Louis 5 Rue Du General Cassagnou68300 Saint-LouisFrance Laboratoire d'etude des Microstructures et de Mecanique des Materiaux(lem3) CNRSUniversite de LorraineArts&Metiers ParisTechF-57000 MetzFrance

The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed *** a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective *** this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical *** experimental method is based on the lateral compression of ring specimens directly machined from the thin and small *** speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested *** Finite Element Updating Method(FEMU)is *** results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket *** of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are *** results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.

关键词： Full metal jacket ammunition Lateral ring compression Inverse identification Numerical simulation

Influence of soil saturation on the free field response of liquefiable soils

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Underground Space 2017年第1期2卷 30-37页

作者： Hanbing Bian Isam Shahrour Yun Jia department of Geotechnical Engineering School of Civil EngineeringTongji UniversityShanghai 200092China lem3 UMR cnrs 7239 Universite de LorraineIle du Saulcy57045 MetzFrance Laboratoire de Genie Civil et geo-Environnement Universite de Lille59650 Villeneuve d’AscqFrance Laboratoire de Mecanique de Lille Universitede Lille59650 Villeneuve d’AscqFrance

The present paper presents analysis of the influence of the soil saturation on the free-field response of liquefiable *** are conducted using a finite element program developed for partially saturated soils subjected to cyclic *** performances of the proposed model are analysed by simulation of undrained triaxial tests with different water *** finite element program is then used for the analysis of the influences of the soil saturation,density and position of the water table on the liquefaction of a soil layer subjected to cyclic *** show that the soil saturation significantly affects the liquefaction of partially saturated sandy *** decrease in the soil saturation results in a reduction of liquefaction risk.

关键词： Free field Liquefaction Dynamic Cyclic loading Seismic Numerical

Toward a Real-Time Framework in Cloudlet-Based Architecture

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Tsinghua Science and Technology 2016年第1期21卷 80-88页

作者： O.Kotevska A.Lbath S.Bouzefrane cnrs LIGUniversity Grenoble Alpes CEDRIC Lab Conservatoire National des Arts et Metiers CNAM

In this study, we present a framework based on a prediction model that facilitates user access to a number of services in a smart living environment. Users must be able to access all available services continuously equipped with mobile devices or smart objects without being impacted by technical constraints such as performance or memory issues, regardless of their physical location and mobility. To achieve this goal, we propose the use of cloudlet-based architecture that serves as distributed cloud resources with specific ranges of influence and a realtime processing framework that tracks events and preferences of the end consumers, predicts their requirements,and recommends services to optimize resource utilization and service response time.

关键词： smart city cloudlet prediction recommendations framework real-time

STATIC REGIME IMAGING OF LOCATIONS OF CERTAIN 3D ELECTROMAGNetIC IMPERFECTIONS FROM A BOUNDARY PERTURBATION FORMULA

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Journal of Computational Mathematics 2014年第4期32卷 412-441页

作者： Seraphin M. Mefire IECL CNRS UMR 7502 Universite de Lorraine Faculte des Sciences et Technologies de Nancy 54506 Vandoeuvre-les-Nancy Cedex France

We are concerned, in a static regime, with a three-dimensional bounded domain of certain an imaging approach of the locations in electromagnetic imperfections. This approach is related to Electrical Impedance Tomography and makes use of a new perturbation formula in the electric fields. We present two localization procedures, from a Current Pro- jection method that deals with the single imperfection context and an inverse Fourier process that is devoted to multiple imperfections configurations. These procedures extend those that were described in our previous work, since operating for a broader class of settings. Namely, the localization is additionally performed for certain purely electric imperfections, as established from numerical simulations.

关键词： Inverse problems Maxwell equations Electric fields Inhomogeneities Elec-trical lmpedanee Tomography Current Projection method FFT Numerical boundarymeasurements Random noise Edge elements Least square systems Incomplete ModifiedGram-Schmidt preconditioning.

Recent progress in augmenting turbulence models with physics-informed machine learning

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Journal of Hydrodynamics 2019年第6期31卷 1153-1158页

作者： Xinlei Zhang Jinlong Wu Olivier Coutier-delgosha Heng Xiao Kevin T.Crofton department of Aerospace and Ocean Engineering Virginia TechBlacksburgVirginiaUSA Laboratoire de Mecanique des Fluides de Lille一Kampe de Feriet Arts et Metiers ParisTechLilleFrance

In view of the long stagnation in traditional turbulence modeling,researchers have attempted using machine learning to augment turbulence *** paper presents some of the recent progresses in our group on augmenting turbulence models with physics-informed machine *** also discuss our works on ensemble-based field inversion to provide training data for constructing machine learning *** and on-going research efforts are introduced.

关键词： Machine learning turbulence modeling data-driven modeling model uncertainty

Influence of manufacturing process-induced geometrical defects on the energy absorption capacity of polymer lattice structures

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defence Technology（防务技术） 2024年第5期35卷 47-59页

作者： Alexandre Riot Enrico Panettieri Antonio Cosculluela Marco Montemurro universite de Bordeaux Arts et Metiers Institute of TechnologyCNRSINRABordeaux INPHESAM UniversiteI2M UMR 5295F-33405 TalenceFrance French Atomic Energy Commission Route des GargailsCedexF-33114Le BarpFrance

Modern additive manufacturing processes enable fabricating architected cellular materials of complex shape,which can be used for different *** them,lattice structures are increasingly used in applications requiring a compromise among lightness and suited mechanical properties,like improved energy absorption capacity and specific stiffness-to-weight and strength-to-weight ratios.A dedicated modeling strategy to assess the energy absorption capacity of lattice structures under uni-axial compression loading is presented in this *** numerical model is developed in a non-linear framework accounting for the strain rate effect on the mechanical responses of the lattice *** geometries,i.e.,cubic body centered cell,octet cell,rhombic-dodecahedron and truncated cuboctahedron 2+,are ***,the influence of the relative density of the representative volume element of each geometry,the strain-rate dependency of the bulk material and of the presence of the manufacturing process-induced geometrical imperfections on the energy absorption capacity of the lattice structure is *** main outcome of this study points out the importance of correctly integrating geometrical imperfections into the modeling strategy when shock absorption applications are aimed for.

关键词： Lattice structures Architected cellular materials Dynamic simulation Energy absorption Geometrical imperfection Additive manufacturing

Impact of B alloying on ductility and phase transition in the Ni–Mn-based magnetic shape memory alloys:Insights from first-principles calculation

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Journal of Materials Science & Technology 2021年第15期74卷 27-34页

作者： Hai-Le Yan Hao-Xuan Liu Ying Zhao Nan Jia Jing Bai Bo Yang Zongbin Li Yudong Zhang Claude Esling Xiang Zhao Liang Zuo Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang 110819China State Key Lab Rolling&Automat Northeastern UniversityShenyang 110819China School of Resources and Materials Northeastern University at Qinhuangdao BranchQinhuangdao 066004China Laboratoire d'etude des Microstructures et de Mecanique des Materiaux(lem3) CNRS UMR 7239Universite de Lorraine57045 Metz.France

Brittleness is a bottleneck hindering the applications of fruitful functional properties of Ni–Mn-based multiferroic ***,experimental studies on B alloying shed new light on this ***,the knowledge related to B alloying is limited until *** importantly,the mechanism of the improved ductility,which is intrinsically related to the chemical bond that is difficult to reveal by routine experiments,is still *** this context,by first-principles calculations,the impact and the correlated mechanism of B alloying were systemically studied by investigating four alloying systems,i.e.,(Ni_(2-x)B_(x))MnGa,Ni_(2)(Mn_(1-x)B_(x))Ga,Ni_(2)Mn(Ga_(1-x)B_(x))and(Ni_(2)MnGa)_(1-x)B_(x).Results show that B prefers the direct occupation manner when it replaces Ni,Mn and *** interstitial doping,B tends to locate at octahedral rather than tetrahedral *** show that the replacement of B for Ga can effectively improve(reduce)the inherent ductility(inherent strength)due to the weaker covalent strength of Ni(Mn)–B compared with Ni(Mn)–*** contrast,B staying at octahedral interstice will lead to the formation of new chemical bonds between Ni(Mn)and B,bringing about a significantly improved strength and a greatly reduced *** the substitutions for Ni and Mn,they affect both the inherent ductility and strength *** phase transition,the replacement of B for Ga tends to destabilize the austenite,which can be understood in the picture of the band Jahn–Teller ***,the substitution for Ga would not lead to an obvious reduction of magnetization.

关键词： Magnetic shape memory alloys Boron alloying Ductility Phase stability First-principles calculation

Ultrasonic fatigue tests at high temperature on an austenitic steel

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Propulsion and Power Research 2012年第1期1卷 29-35页

作者： D.Wagner F.J.Cavalieri C.Bathias N.Ranc Laboratoire Energetique Mecanique Electromagnetisme Universite Paris Ouest92410 Ville D’AvrayFrance LMSP Arts et Metiers-ParisTech75013 ParisFrance

The objective of this paper is to study the gigacycle fatigue behavior of an austenitic steel at temperatures of 6001C and 700℃under fully reverse loading(R=-1).Numerical simulation by finite element method(FEM)was used to design the specimens and to analyze the effects of the variation in the dynamic Young modulus with temperature from measurements of the ultrasonic resonance ***,new stress-life curves for this material are presented for a lifetime range from 10^(5)to 10^(9)cycles at room temperature,600℃and 700℃.

关键词： Fatigue Gigacycle regime High temperature Austenitic steel Finite element method Crack initiation mechanism

Time till death affects spider mobility and web-building behavior during web construction in an orb-web spider

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Current Zoology 2016年第2期62卷 123-130页

作者： Mylene ANOTAUX Camille TOSCANI Raymond LEBORGNE Nicolas CHALINE Alain PASQUet Faculte des Sciences et Technologies Universite de Lorraine 54506 Vandoeuvre Nancy France Ecole nationale veterinaire d'Alfort Universite Paris-Est UMR 7179 CNRS MNHN Maisons-Alfort F-94704 France Laboratoire d'ethologie Experimentale et Comparee EA 4443 universite Paris 13 99 avenue J.B. Clement 93430 Villetaneuse France Faculte des Sciences et Technologies Universite de Lorraine CNRS UR AFPA. B.P. 239 54506 Vandoeuvre Nancy France

It is well known that age influences organism mobility. This was demonstrated in vertebrates （such as mammals and birds） but has been less studied in invertebrates with the exception of Drosophila and the nematode Caenorhabditis elegans. Here we studied the influence of age on the mobility of the orb-weaving spider Zygiella x-notata during web construction. The orb-web is a good model because it has a characteristic geometrical structure and video tracking can be used to easily follow the spider＇s movements during web building. We investigated the influence of age （specifically chronological age, life span, and time till death） on different parameters of spider mobility during the construction of the capture spiral （distance traveled, duration of construction, spider velocity, spider movement, and spider inactivity） with a generalized linear model （GLM） procedure adjusted for the spider mass. The re- sults showed that neither chronological age, nor life span affected the mobility parameters. However, when the time till death decreased, there was a decrease in the distance traveled, the duration of the construction of the capture spiral, and the spider movement. The spider velocity and the time of inactivity were not affected. These results could be correlated with a decrease in the length of the silky thread deposited for the construction of the capture spiral. Spiders with a shorter time till death built smaller web using less silk. Thus, our study suggests strongly that time till death affects spider mobility during web construction but not the chronological age and thus may be a good indicator of senescence.

关键词： ageing behaviors orb-web construction spider mobility Zygiella x-notata.