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An Elastoplastic Damage Constitutive Model for Concrete

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China Ocean Engineering 2013年第2期27卷 169-182页

作者：刘军林皋钟红 School of Civil&Safety Engineering Dalian Jiaotong University Faculty of Infrastructure Engineering Dalian University of Technology

An elastoplastic damage constitutive model to simulate nonlinear behavior of concrete is presented. Similar to traditional plastic theory, the irreversible deformation is modeled in effective stress space. In order to better describe different stiffness degradation mechanisms of concrete under tensile and compressive loading conditions, two damage variables, i.e., tension and compression are introduced, to quantitatively evaluate the degree of deterioration of concrete structure. The rate dependent behavior is taken into account, and this model is derived firmly in the framework of irreversible thermodynamics. Fully implicit backward-Euler algorithm is suggested to perform constitutive integration. Numerical results of the model accord well with the test results for specimens under uniaxial tension and compression, biaxial loading and triaxial loading. Failure processes of double-edge-notched （DEN） specimen are also simulated to further validate the proposed model.

关键词： constitutive model elastoplastic-damage irreversible thermodynamics energy release rate concrete

Coupled viscoplasticity damage constitutive model for concrete materials

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Applied Mathematics and Mechanics(English Edition) 2007年第9期28卷 1145-1152页

作者：刘长春吕和祥关萍 State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian University

A coupled viscoplasticity damage constitutive model for concrete materials is developed within the framework of irreversible thermodynamics. Simultaneously the Hehnholtz free energy function and a non-associated flow potential function are given, which include the internal variables of kinematic hardening, isotropic hardening and damage. Results from the numerical simulation show that the model presented can describe the deformatioa properties of the concrete without the formal hypotheses of yield criterion and failure criteria, such as the volume dilatancy under the compression, strain-rate sensitivity, stiffness degradation and stress-softening behavior beyond the peak stress which are brought by damages and fractures. Moreover, we could benefit from the application of the finite element method based oi1 this model under complex loading because of not having to choose different constitutive models based on the deformation level.

关键词： concrete viscoplasticity damage irreversible thermodynamics

SOLUTIONS FOR CYLINDRICAL CAVITY IN SATURATED THERMOPOROELASTIC MEDIUM

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Acta Mechanica Solida Sinica 2009年第1期22卷 85-94页

作者： Bing Bai Tao Li School of Civil Engineering Beijing Jiaotong University Beijing 100044 China

Based on the thermodynamics of irreversible processes, the mass conservation equation and heat energy balance equation are established. The governing equations of thermal consolidation for homogeneous isotropic materials are presented, accounting for the coupling effects of the temperature, stress and displacement fields. The case of a saturated medium with a long cylindrical cavity subjected to a variable thermal loading and a variable hydrostatic pressure （or a variable radial water flux） with time is considered. The analytical solutions are derived in the Laplace transform space. Then, the time domain solutions are obtained by a numerical inversion scheme. The results of a typical example indicate that thermodynamically coupled effects have considerable influences on thermal responses.

关键词： cylindrical cavity boundary conditions irreversible thermodynamics thermo-osmosis,Laplace transform

Weak Wavefront Solutions of Maxwell’s Equations in Conducting Media

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Journal of Applied Mathematics and Physics 2022年第1期10卷 190-199页

作者： Michael Grinfeld Pavel Grinfeld The U.S. Army Research Laboratory WMRD Aberdeen Proving Ground Harford County USA Mathematics Department Drexel University Philadelphia USA

We analyze the propagation of electromagnetic fronts in unbounded electric conductors. Our analysis is based on the Maxwell model of electromagnetism that includes the displacement current and Ohm’s law in its simplest forms. A weak electromagnetic front is a propagating interface at which the electromagnetic field remains continuous while its first- and higher-order derivatives experience finite jump discontinuities. Remarkably, analysis of such fronts can be performed autonomously, i.e. strictly in terms of the quantities defined on the front. This property opens the possibility of establishing exact analytical solutions of the exact Maxwell system along with the evolution of the front.

关键词： Electric Current in Conductors irreversible thermodynamics Alegra Verification Boundary Value Problems Exact Solution

CRITERION FOR JUDGING SATISFACTION OF CONSISTENCY CONDITIONS IN RATE-DEPENDENT CONSTITUTIVE RELATIONS

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维普期刊数据库

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Acta Mechanica Solida Sinica 1999年第4期12卷 356-364页

作者： Wang Zhe (College of Civil Engineering and Architecture,Northern Jiaotong University,Beijing 100044,China) Coll. of Civ. Eng. and Architecture Northern Jiaotong University Beijing 100044 China

Based on irreversible thermodynamics, the criterion for judging the satisfaction of consistency conditions in rate-dependent constitutive relationship is deduced by introducing four basic hypotheses. Formulas for solving internal variables are given. It makes the rate-dependent model applicable no matter whether the consistency conditions can be satisfied or not.

关键词： rate-dependent constitutive relations consistency condition irreversible thermodynamics

GENERAL EXPRESSIONS OF CONSTITUTIVE EQUATIONS FOR ISOTROPIC ELASTIC DAMAGED MATERIALS

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Applied Mathematics and Mechanics(English Edition) 2001年第12期22卷 1468-1475页

作者：唐雪松蒋持平郑健龙 Department of Flight Vehicle Design and Applied Mechanics Beijing University of Aeronautics and Astronautics Beijing 100083 P R ChinaDepartment of Bridge and Structure Engineering Changsha Jiaotong University Changsha 410076 P R China Department of Flight Vehicle Design and Applied Mechanics Beijing University of Aeronautics and Astronautics Beijing 100083 P R China Department of Highway and Communications Engineering Changsha Jiaotong University Changsha 410076 P R China

The general expressions of constitutive equations for isotropic elastic damaged materials were derived directly from the basic law of irreversible thermodynamics. The limitations of the classical damage constitutive equation based on the well-known strain equivalence hypothesis were overcome. The relationships between the two elastic isotropic damage models (i.e. single and double scalar damage models) were revealed. When a single scalar damage variable defined according to the microscopic geometry of a damaged material is used to describle the isotropic damage state, the constitutive equations contain two 'damage effect functions', which describe the different influences of damage on the two independent elastic, constants. The classical damage constitutive equation based on the strain equivalence hypothesis is only the first-order approximation of the general expression. It may be unduly simplified and may fail to describe satisfactorily the damage phenomena of practical materials.

关键词： damage mechanics irreversible thermodynamics elastic damage constitutive equation

DYNAMIC CHARACTERISTICS OF AXIALLY SYMMETRIC SUPERSONIC FLOW UNDER MICROWAVE CONDITIONS

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DYNAMIC CHARACTERISTICS OF AXIALLY SYMMETRIC SUPERSONIC FLOW...

Performance Analysis of an irreversible Refrigerator with Finite Thermal Capacity Reservoirs

2002 3rd International Conference on Microwave and Millimeter Wave Technology

作者： Zhao Qingxun Ding Wenge Zhang Kaixi College of Physics Science and Technology Hebei University

ISBN: (纸本)078037486X

＜正＞Using supersonic dynamic and Onsager potential transfer differential equation of irreversible process thermodynamic,dynamic characteristics of axially symmetric supersonic flow radiated by microwave beam has been studied *** results corresponding to this research are relatively satisfied in comparison with experimental *** is useful to study parameters of the plasma by ultrasonic method for the plasma diagnostics.

关键词： irreversible thermodynamics supersonic flow axial symmetry plasma diagnostics plasma interactions plasma radiofrequency heating microwave beam radiated axially symmetric supersonic flows supersonic dynamics Onsager potential transfer differential equation irreversible process thermodynamics supersonic flow dynamic characteristics ultrasonic plasma parameter study method plasma diagnostics plasma interactions

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cnki会议

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Journal of Donghua University(English Edition) 2017年第4期34卷 529-532页

作者：赵刘波黄跃武 College of Environmental Science and Engineering Donghua UniversityShanghai 201620China

To explore the influence of heat reservoirs of total thermal capacity at high and low temperature side heat exchanger of an irreversible refrigeration cycle on the coefficient of performance,the cycle model is established. By using the irreversible thermodynamics,much progress had been made in the studies of thermal resistance,heat leak and irreversible factors on the cycle of the coefficient of performance. The analytical formula of coefficient of performance and the distribution ratio of total thermal capacity are derived when the total thermal capacity at high and low temperature side heat exchanger is a constant. The influences of cycle parameters and different kinds of irreversible factors on the coefficient of performance and the optimal distribution ratio are analyzed by numerical computation. The results indicate that the coefficient of performance increases with the increase of the total heat capacity,and decreases with heat leak and internal irreversible factors. Furthermore,the optimal distribution ratio of total thermal capacity,when coefficient of performance reaches the maximum value,only has a connection with the internal dissipation.

关键词： irreversible thermodynamics refrigeration cycle optimization

Paraelectric-ferroelectric interface dynamics induced by latent heat transfer and irreversibility of ferroelectric phase transitions

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Chinese Physics B 2006年第6期15卷 1364-1369页

作者：艾树涛 Department of Physics and Institute of Condensed Matter Physics Linyi Normal University Linyi 276005 China

The temperature gradients that arise in the paraelectric-ferroelectric interface dynamics induced by the latent heat transfer are studied from the point of view that a ferroelectric phase transition is a stationary, thermal-electric coupled transport process. The local entropy production is derived for a ferroelectric phase transition system from the Gibbs equation. Three types of regions in the system are described well by using the Onsager relations and the principle of minimum entropy production. The theoretical results coincides with the experimental ones.

关键词： ferroelectric phase transition interface dynamics irreversible thermodynamics