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Development of a unified viscoplasticity constitutive model based on classical plasticity theory

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Science China(Technological Sciences) 2009年第5期52卷 1248-1253页

作者： GUAN Ping LIU ChangChun Lü HeXiang College of Architectural Engineering Dalian UniversityDalian 116622China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China

The traditional unified viscoplasticity constitutive model can be only applied to metal materials.The study of the unified constitutive theory for metal materials has discovered the correlation between the classical plasticity theory and the unified viscoplasticity constitutive model,thus leading to the con-cepts of the classic plastic potential and yield surface in the unified constitutive model.Moreover,this research has given the continuous expression of the classical plastic multiplier and presented the corresponding constructive method,which extends its physical significance and lays down a good foundation for the application of the unified constitutive theory to the material analysis in more fields.This paper also introduces the unified constitutive model for metal materials and geo-materials.The numerical simulation indicates that the construction should be both reasonable and practical.

关键词： viscoplasticity classical plasticity unified constitutive model plastic potential yield surface

A unified viscoplasticity constitutive model based on irreversible thermodynamics

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Science China(Technological Sciences) 2008年第4期51卷 378-385页

作者： LIU ChangChun Lü HeXiang GUAN Ping State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China Prediction&Control Key Laboratory on Complicated Structure System Dalian UniversityDalian 116622China

A unified viscoplasticity constitutive model for metal materials is developed within the framework of irreversible thermodynamics, and an expression for the Helmholtz free energy function involving the parameters reflecting kinematic hardening and isotropic hardening is given. At the same time a non-associated flow potential function including the corresponding state variables is also given, from which the flow equation and the evolution equations of the internal state variables are derived. Thus, a general theoretical framework constructing a unified viscoplasticity constitutive model is given. Compared with the typical unified viscoplasticity constitutive models, the presented model evidently satisfies the irreversible thermodynamics laws. Moreover, this method not only provides a new theoretical foundation for further development of the unified viscoplasticity constitutive model, but also gives a new theoretical framework for the stress-strain analysis of more materials.

关键词： irreversible thermodynamics viscoplasticity unified constitutive kinematic hardening isotropic hardening

THE PARAMETRIC VARIATIONAL PRINCIPLE FOR PERZYNA MODEL IN viscoplasticity

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Applied Mathematics and Mechanics(English Edition) 1991年第5期12卷 433-437页

作者：曾攀钟成勰 Research Institute of Engineering Mechanics Dalian University of Technology Dalian

This paper presents the parametric variational principle for Perzyna model which is one of the main constitutive relations of viscoplasticity.The principle,by which the potential energy function is minimized under a constrained condition transformed by the constitutive relations of viscoplasticity, is free from the bound of Drucker's postulate of plastic flow and consequently suitable for solving the nonassociated plastic flow problems. Furthermore, the paper has proven the presented principle and discussed the creep problem.

关键词： viscoplasticity parametric variational principle,creep

SYMMETRIC FORMULATION OF TANGENTIAL STIFFNESSES FOR NON-ASSOCIATED viscoplasticity WITH AN IMPLICIT TIME INTEGRATION SCHEME

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Applied Mathematics and Mechanics(English Edition) 1993年第3期14卷 269-276页

作者：熊文林 Wuhan University of Hydraulic and Electric Engineering Wuhan

A numerical scheme is presented which enables the use of symmetric equation solvers in tangential stiffness programs for non-associated viscoplastic materials.

关键词： viscoplasticity non-associated tangential stiffnesses symmetric

Enhancing the elastoplastic damage constitutive model for clayey rocks: Incorporating anisotropy, saturation, time-dependent, and debonding effects

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2291-2312页

作者： Jueliang Chen Siyu Liu Wanqing Shen Jianfu Shao Minh-Ngoc Vu Wenzhou Key Laboratory of Intelligent Lifeline Protection and Emergency Technology for Resilient City College of Architecture and Energy EngineeringWenzhou University of TechnologyWenzhou325000China Department of Civil Engineering Polytech LilleUniversity of LilleLaMcube59000LilleFrance College of Civil Engineering and Transportation HOHAI UniversityNanjingChina Andra 92298Chatenay MalabryFrance

This paper introduced a novel microstructure-based constitutive model designed to comprehensively characterize the intricate mechanical behavior of anisotropic clay rocks under the influence of water saturation.The proposed model encompasses elastoplastic deformation,time-dependent behavior,and induced damage.A two-step homogenization process incorporates mineral compositions and porosity to determine the macroscopic elastic tensor and plastic yield criterion.The model also considers interfacial debonding between the matrix and inclusions to capture rock damage.The application of the proposed model is demonstrated through an analysis of Callovo-Oxfordian clayey rocks,specifically in the context of radioactive waste disposal in France.Model parameters are determined,followed by numerical simulations of various laboratory tests including lateral decompression tests with constant mean stress,triaxial compression tests under different water saturation conditions,and creep tests.The numerical results are compared with corresponding experimental data to assess the efficacy of the proposed model.

关键词： Clayey rocks Micromechanics Anisotropy Plasticity viscoplasticity Debonding damage Saturation

A hydromechanical approach for anisotropic elasto-viscoplastic geomaterials:Application to underground excavations in sedimentary rocks

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Underground Space 2019年第2期4卷 109-120页

作者： Mohamed Mahjoub Ahmed Rouabhi Mines ParisTech PSL Research UniversityCentre de Ge´osciencesFontainebleauFrance

To better describe excavation operations in deep geological formations,several aspects should be considered,especially the material anisotropy,time-dependent behavior,and hydromechanical coupling.In the present paper,a hydromechanical model based on the framework of continuous porous media was proposed.The mechanical elasto-viscoplastic constitutive model accounted for the material elastic and non-elastic anisotropies,using a transformation between the real transversely isotropic material and a fictitious isotropic material.Considering the hydraulic behavior,the permeability was expressed as a function of the volumetric viscoplastic strain.The model was applied to a case study of two tunnel excavations in an anisotropic rock under an initial anisotropic stress state.The results of the numerical simulations using a finite element code were in good agreement with the field convergence and permeability data.

关键词： Hydromechanical behavior Transverse isotropy Tunnel excavation viscoplasticity Permeability

A unified plasticity methodology for rate-and temperature-sensitive alloys exhibiting a non-linear kinematic hardening behavior

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Acta Mechanica Solida Sinica 2017年第1期30卷 27-37页

作者： Jacques Luk-Cyr Daniel Paquet Jacques Lanteigne Henri Champliaud Aurelian Vadean Department of Mechanical Engineering Ecole Polyechnique de Montreal 2900 Blvd Edouard-Montpetit MontrealQC H3T 1J4 Institut de recherche d'Hydro-Quebec 1800 Blvd Lionel-Boulet Varennes QC J3X 1S1 Department of Mechanical Engineering Ecole de technologie superieure 1100 Rue Notre-Dame O Montreal QCH3C 1K3

In this paper, a novel unified plasticity methodology is proposed to allow the coupling of rate-and temperature-sensitivity of engineering alloys as well as the non-linear kinematic hardening behavior often observed during cyclic loading. The proposed methodology is general in the sense that an arbitrary constitutive model may be chosen for the viscoplastic part, as well as the cyclic part. We adapt our model with a physically-motivated viscoplasticity flow rule and a nonlinear kinematic hardening model. In contrast with other unified plasticity models, the simplified theory involves few material parameters that can be readily calibrated from standard mechanical tests. The capabilities of the proposed theory are demonstrated for a hot rolled annealed 304 L stainless steel supplied by Vimetal Peckover. The model is tested with stress–strain curves obtained from standard tensile and cyclic uniaxial tests at various strain amplitudes and strain-rates, and good accuracy of the response is obtained for strains up to 15%, within a temperature range of 293–673 K. We note that the cyclic plasticity model in our adapted theory can be readily enhanced with ratchetting, mean stress relaxation, strain amplitude history, Masing effects or other complex capabilities.

关键词： Unified plasticity Constitutive behavior viscoplasticity Non-linear kinematic hardening Stainless steels

Rheological Properties of Polyamide: Experimental Studies and Constitutive Modeling

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Chinese Journal of Polymer Science 2019年第2期37卷 178-188页

作者： Cyprian Suchocki Rafa? Molak Fundamental Technical Sciences Division Warsaw University of Life Sciences Faculty of Materials Science and Engineering Warsaw University of Technology

This work is focused on simulating the rheological effects in polyamide. An experimental study is carried out in order to assess such features of polyamide as: the hysteretic behavior, the strain rate dependence, and the stress relaxation. The material response in tension is investigated. Digital images correlation method(DIC) is employed in order to measure the material compressibility. A newly developed constitutive model, which was previously used to simulate the mechanical response of polyethylene subjected to moderate strains and compressive loadings, is applied to capture the large strain, inelastic behavior of polyamide in tension. The gathered experimental data are utilized to determine the values of constitutive constants of viscoelasticity and plasticity, which describe the rheological properties of polyamide. The determined material parameters are included in the text. Different strategies for evaluating the material parameters are discussed. The proposed constitutive equation is implemented into the finite element(FE) system, ABAQUS, by taking advantage of the user subroutine UMAT, which allows to define custom material laws. Some exemplary FE simulations that were used to investigate the performance of the developed subroutine are described.

关键词： Polyamide viscoplasticity Material parameters:Finite element method UMAT

A chemo-mechanical model for fully-coupled lithiation reaction and stress generation in viscoplastic lithiated silicon

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Science China(Technological Sciences) 2019年第8期62卷 1365-1374页

作者： BUREBI Yi Ming JIA Zheng QU ShaoXing Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Center for X-MechanicsDepartment of Engineering MechanicsZhejiang University

Development of stresses in silicon(Si) anodes of lithium-ion batteries is strongly affected by its mechanical properties. Recent experiments reveal that the mechanical behavior of lithiated silicon is viscoplastic, thereby indicating that lithiation-induced mechanical stresses are dependent on the lithiation reaction rate. Experimental evidence also accumulates that the rate of lithiation reaction is conversely affected by the magnitude of mechanical stresses. These experimental observations demonstrate that lithiation reaction and stress generation in silicon anodes are fully coupled. In this work, we formulate a chemo-mechanical model considering the two-way coupling between lithiation reaction and viscoplastic deformation in silicon nanoparticle anodes.Based on the model, the position of the lithiation interface, the interface velocity, and the lithiation-induced stresses can be solved simultaneously via numerical methods. The predicted interface velocity is in line with experimental measurements reported in the literature. We demonstrate that the lithiation-induced stress field depends on the lithiation reaction through two parameters:the migration velocity and the position of the lithiation interface. We identify a stress-mitigation mechanism in viscoplastic silicon anodes: the stress-regulated lithiation reaction at the interface serves as a "brake" to reduce the interface velocity and mitigate the lithiation-induced stresses, protecting the Si nanoparticle anode from being subjected to excessive mechanical stresses.

关键词： lithium-ion battery lithiation-induced stress stress-regulated lithiation viscoplasticity