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Anisotropic modelling of Opalinus Clay behaviour: From triaxial tests to gallery excavation application

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第3期9卷 53-66页

作者： Francois Bertrand Frédéric Collin Université de Liège Département ArGEnCo/Géomécanique Allée de la découverte 9 4000 Liège Belgium F.R.I.A Fonds de la Recherche Scientifique e FNRS Brussels Belgium

Deep repository in geological formations is the preferential solution considered in many countries to manage high-level nuclear wastes. In Switzerland, the Opalinus Clay is a candidate host rock. In this context, in situ and laboratory tests are conducted on Opalinus Clay to demonstrate the feasibility of deep disposal in this argillaceous formation. This paper presents a constitutive model able to fit the experimental data obtained from some triaxial tests conducted by Jahns(2013) on cores from borehole Schlattingen SLA-1. The elasto-plastic behaviour of Opalinus Clay is reproduced thanks to a DruckerPrager model, taking into account the anisotropy behaviour of this sedimentary rock. The objective is to employ a single set of parameters representative of the material. In a second version of the model, the stress-dependence of the elastic properties and damage are taken into account. Finally, the parameters calibrated with experimental tests are used to simulate the excavation of a gallery with a second gradient approach.

关键词： Opalinus Clay Schlattingen constitutive modelling Anisotropy Dilatancy Localisation Tunnel excavation

Investigation of the hydro-mechanical behaviour of fouled ballast

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 244-255页

作者： Yu-jun CUI Trong Vinh DUONG Anh Minh TANG Jean-Claude DUPLA Nicolas CALON Alain ROBINET Laboratoire Navier/CERMES Ecole des Ponts ParisTechBlaise PascalCité DescartesChamps-sur-Marne 77455 Marne-la-Vallée Cedex-France French National Railway Company 93574La Plaine St DenisFrance

In this study,a fouled ballast taken from the site of Sénissiat,France,was *** the hydraulic behaviour,a large-scale cell was developed allowing drainage and evaporation tests to be carried out with monitoring of both suction and volumetric water content at various positions of the *** was observed that the hydraulic conductivity of fouled ballast is decreasing with suction increase,as for common unsaturated *** effect of fines content was found to be *** the mechanical behaviour,both monotonic and cyclic triaxial tests were carried out using a large-scale triaxial *** water contents were *** results were interpreted in terms of shear strength and permanent axial *** appeared that the water content is an important factor to be accounted for since any increase of water content or degree of saturation significantly decreases the shear strength and increases the permanent *** modelling has been attempted based on the experimental *** model in its current state is capable of describing the effects of stress level,cycle number and water content.

关键词： Fouled ballast Degree of saturation Hydraulic behaviour Mechanical behaviour Fines content constitutive modelling

A bayesian optimisation methodology for the inverse derivation of viscoplasticity model constants in high strain-rate simulations

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Defence Technology（防务技术） 2022年第9期18卷 1563-1577页

作者： Shannon Ryan Julian Berk Santu Rana Brodie McDonald Svetha Venkatesh Applied Artificial Intelligence Institute(A^(2)I^(2)) Deakin University75 Pigdons RdWaurn PondsVIC3216Australia Defence Science and Technology Group 506 Lorimer StreetFishermans BendVIC3207Australia

We present an inverse methodology for deriving viscoplasticity constitutive model parameters for use in explicit finite element simulations of dynamic processes using functional experiments, i.e., those which provide value beyond that of constitutive model development. The developed methodology utilises Bayesian optimisation to minimise the error between experimental measurements and numerical simulations performed in LS-DYNA. We demonstrate the optimisation methodology using high hardness armour steels across three types of experiments that induce a wide range of loading conditions: ballistic penetration, rod-on-anvil, and near-field blast deformation. By utilising such a broad range of conditions for the optimisation, the resulting constitutive model parameters are generalised, i.e., applicable across the range of loading conditions encompassed the by those experiments(e.g., stress states, plastic strain magnitudes, strain rates, etc.). Model constants identified using this methodology are demonstrated to provide a generalisable model with superior predictive accuracy than those derived from conventional mechanical characterisation experiments or optimised from a single experimental condition.

关键词： constitutive modelling Finite element Bayesian optimisation Finite element model updating

Deep Learning Predicts Stress–Strain Relations of Granular Materials Based on Triaxial Testing Data

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Computer Modeling in Engineering & Sciences 2021年第7期128卷 129-144页

作者： Tongming Qu Shaocheng Di Y.T.Feng Min Wang Tingting Zhao Mengqi Wang Zienkiewicz Centre for Computational Engineering College of EngineeringSwansea UniversitySwanseaWalesSA18EPUK College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China Institute of Applied Mechanics and Biomedical Engineering Taiyuan University of TechnologyTaiyuan030024China Fluid Dynamics and Solid Mechanics Group Theoretical DivisionLos Alamos National LaboratoryLos AlamosNM 87545USA

This study presents an AI-based constitutive modelling framework wherein the prediction model directly learns from triaxial testing data by combining discrete element modelling(DEM)and deep learning.A constitutive learning strategy is proposed based on the generally accepted frame-indifference assumption in constructing material constitutive *** low-dimensional principal stress-strain sequence pairs,measured from discrete element modelling of triaxial testing,are used to train recurrent neural networks,and then the predicted principal stress sequence is augmented to other high-dimensional or general stress tensor via coordinate *** detailed hyperparameter investigations,it is found that long short-term memory(LSTM)and gated recurrent unit(GRU)networks have similar prediction performance in constitutive modelling problems,and both satisfactorily predict the stress responses of granular materials subjected to a given unseen strain ***,the unique merits and ongoing challenges of data-driven constitutive models for granular materials are discussed.

关键词： Deep learning granular materials constitutive modelling discrete element modelling coordinate transformation LSTM GRU

Grain crushing in geoscience materials-Key issues on crushing response,measurement and modeling:Review and preface

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Geoscience Frontiers 2020年第2期11卷 363-374页

作者： Yang Xiao Chandrakant SDesai Ali Daouadji Armin WStuedlein Hanlong Liu Hossam Abuel-Naga Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China School of Civil Engineering Chongqing UniversityChongqing 400045China Dept.of Civil Engineering and Engineering Mechanics Univ.of ArizonaTucsonAZ85721USA Universite de Lyon INSA LYONLaboratoire GEOMASJ.C.A.Coulomb34 Avenue des Arts69621VilleurbanneFrance School of Civil and Construction Engineering Oregon State UniversityCorvallisOR97331USA Chongqing University Chongqing 400045China School of Engineering and Mathematical Sciences La Trobe UniversityVictoria3086Australia

Grain crushing is commonly encountered in deep foundation engineering,high rockfill dam engineering,railway engineering,mining engineering,coastal engineering,petroleum engineering,and other geoscience *** crushing is affected by fundamental soil characteristics,such as their mineral strength,grain size and distribution,grain shape,density and specimen size,and also by external factors including stress magnitude and path,loading rate and duration,degree of saturation,temperature and geochemical *** material becomes a series of different materials with the change in its grading during grain crushing,resulting in a decrease in strength and dilatancy and an increase in *** of grain crushing on strength,dilatancy,deformation and failure mechanisms have been extensively investigated through laboratory testing,discrete element method(DEM)modelling,Weibull statistics,and constitutive modelling within the framework of the extended crushing-dependent critical state theory or the energy-based *** papers summarized in this review article for this special issue addressed the above issues in grain crushing through the advanced testing and modelling.

关键词： Grain crushing Particle breakage Strength Dilatancy DEM modelling constitutive modelling

ON THE DESCRIPTION OF ANISOTROPIC DAMAGE IN COMPOSITE LAMINATES

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Acta Mechanica Sinica 1991年第4期7卷 335-343页

作者：杨卫 J.P.Boehler Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China Institut de Me’canique de Grenoble University Joseph FourierGrenoble I.38041 Grenoble CedexFrance

A general anisotropic damage theory of cracked laminates is formulated *** deformation of composite laminates is composed of matrix elastic strains,pseudo-elastic damage strains due to cracking and permanent damage strains due to interlaminar *** surface of damage initiation is constructed accord- ing to the concept of linear elastic fracture mechanics for the virgin *** the initial damage,a pesudo-elastic damage can be used to describe the damage behaviour if interlaminar slip is *** evolution,load induced anisotropy and interlaminar-intralaminar interaction for composite laminates are exam- ined;the latter can perturb the normality structure of damage strain *** expressions are given for pseudo-elastic (or secant) moduli of the damaging composite laminates,under a non-interacting assumption imposed on the cracks between different families.

关键词： composite laminates anisotropic damage constitutive modelling

modelling and Simulation on the Effect of Hot Forming Damage on Three-Point Bending Performance of Beam Components

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Journal of Beijing Institute of Technology 2020年第3期29卷 399-409页

作者： Weimin Zhuang Pengyue Wang Yang Liu Dongxuan Xie Hongda Shi State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China FAW-Volkswagen Automotive Co. Ltd.Changchun 130011China

The effects of forming damage are analyzed,which occur during hot stamping process,on the load-carrying capacity and failure mode of hot stamped beams.A damage-coupled pre-forming constitutive model was proposed,in which the damage during hot stamping process was introduced into the service *** constitutive model was applied into the three-point bending simulation of a hot stamped beam,and then the influences of forming damage on the load-carrying capacity and cracks propagation were *** results show that the forming damage reduces the maximum load capacity of the hot stamped beam by 7.5%.It also causes the crack to occur earlier and promotes crack to propagate along the radial direction of the punch.

关键词： constitutive modelling hot-stamped beam forming damage three-point bending crack propagation

A unified constitutive model for multiphase precipitation and multi-stage creep ageing behavior of Al−Li−S4 alloy

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Transactions of Nonferrous Metals Society of China 2021年第5期31卷 1217-1234页

作者： He LI Li-hua ZHAN Ming-hui HUANG Xing ZHAO Chang ZHOU Li-bin HU Zheng-gen HU De-bo LIU Light Alloy Research Institute Central South UniversityChangsha 410083China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of High-Performance Complex Manufacturing Central South UniversityChangsha 410083China Beijing Institute of Astronautic Systems Engineering Beijing 100076China

A unified constitutive model is presented to predict the recently observed“multi-stage”creep behavior of Al−Li−S4 *** corresponding microstructural variables related to the yield strength and creep deformation of the alloy during the creep ageing process,including dislocations and multiple precipitates,have been characterized in detail by X-ray diffraction(XRD)and transmission electron microscopy(TEM).For the yield strength,the model considers the multiphase strengthening behavior of the alloy based on strengthening mechanisms,which includes shearable T1 precipitate strengthening,non-shearable T1 precipitate strengthening andθ′precipitate *** on creep deformation mechanism,the“multi-stage”creep behavior of the alloy is predicted by introducing the effects of interacting microstructural variables,including the radius of multiple precipitates,dislocation density and solute concentration,into the creep stress−strain *** is concluded that the results calculated by the model are in a good agreement with the experimental data,which validates the proposed model.

关键词： constitutive modelling Al−Li−S4 alloy creep age forming microstructures numerical algorithms