Study on Non-Local Damage Constitutive Model of Concrete under Freeze-Thaw Action

2010 ◽  
Vol 452-453 ◽  
pp. 133-136 ◽  
Author(s):  
Zong Min Liu ◽  
Ji Ze Mao ◽  
Hai Yan Song
Keyword(s):  
Constitutive Model ◽  
Internal State ◽  
Constitutive Relations ◽  
Irreversible Thermodynamics ◽  
Local Damage ◽  
Variable Theory ◽  
Freeze Thaw ◽  
Adjacent Point ◽  
Damage Constitutive Model ◽  
Non Local

Concrete is multi-phase composites. Due to the inhomogeneity of mechanical properties and complexity of physical properties, constitutive relations of concrete are more complicated. Starting from irreversible thermodynamics theory, internal state variable theory and nonlocal field theory, non-local damage constitutive model of concrete under freeze-thaw action is established in this paper. In the model, non-local influence functions are discussed which are used to describe interplay of damage between adjacent point.

scholarly journals A Damage Constitutive Model of Rock Subjected to Freeze-Thaw Cycles Based on Lognormal Distribution

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Hang Lin ◽  
Linyuan Liang ◽  
Yifan Chen ◽  
Rihong Cao
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Lognormal Distribution ◽  
Constitutive Models ◽  
Strain Curve ◽  
Statistical Distribution ◽  
Freeze Thaw ◽  
Accurate Quantitative Analysis ◽  
Distribution Parameters ◽  
Damage Constitutive Model

The constitutive model of rock is closely connected with the mechanical properties of rock. To achieve a more accurate quantitative analysis of the mechanical properties of rock after the action of freeze-thaw cycles, it is necessary to establish the constitutive models of rock subjected to freeze-thaw cycles from the view of rock damage. Based on the assumption of rock couple damage, this study established a statistical damage constitutive model of rock subjected to freeze-thaw cycles by combining the lognormal distribution, which is commonly used in engineering reliability analysis, and the strain strength theory. Then, the coordinates and derivative at the peak of the stress-strain curve of the rock after the action of freeze-thaw cycles were obtained through experiments to solve the statistical distribution parameters με and S of the model, whereafter, the theoretical curves by the established model were compared with the experimental curves to verify the validity of it, which shows a great agreement. Finally, the sensitivity analysis of the statistical distribution parameters was implemented. The results indicate that με reflects the strength of the rock, which shows a positive relation, and S stands for the brittleness of the rock, which shows a negative relation.

Uniaxial Compression Fractal Damage Constitutive Model of Rock Subjected to Freezing and Thawing

2020 ◽  
Author(s):  
Shengtao Zhou ◽  
Nan Jiang ◽  
Xuedong Luo ◽  
Wen Fang ◽  
Xu He
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Uniaxial Compression ◽  
Residual Strength ◽  
Structural Damage ◽  
Compression Fracture ◽  
Peak Strain ◽  
Freeze Thaw ◽  
Deformation Stage ◽  
Damage Constitutive Model

Mechanical properties of the rock in the cold regions are often affected by freeze-thaw cycles and loads. It is of great theoretical significance and engineering value to establish a uniaxial compression damage constitutive model of the rock under freeze-thaw cycles that can reflect the relationship between macroscopic and mesoscopic structural damage. In this paper, macroscopic and mesoscopic methods are combined with statistical methods to quantitatively analyze the damage degree of rock under freeze-thaw cycles and loads. Combined with the fractal features of the macroscopic image of the section, a fractal damage constitutive model considering the residual strength of rock is established. In addition, the model is subsequently verified by the experiment. The experiment shows that the mechanical properties of rocks subjected to freeze-thaw cycles and loads are determined by freeze-thaw damage variables, load damage variables, and their coupling effects. As the number of freeze-thaw cycles increases, the uniaxial compressive strength and elastic modulus of rocks decrease, and peak strain increases. By using the fractal dimension of the compression fracture surface as a bridge considering the residual strength of the rock, the constitutive model can better reflect the compaction stage, elastic deformation stage and plastic deformation stage of the uniaxial compression process of the freeze-thaw rocks.

Thermodynamics of Infinitesimally Constrained Equilibrium States

2008 ◽  
Vol 76 (1) ◽  
Author(s):  
Q. Yang ◽  
L. J. Xue ◽  
Y. R. Liu
Keyword(s):  
Constitutive Relations ◽  
Hessian Matrix ◽  
Coefficient Matrix ◽  
Internal Variable ◽  
Irreversible Thermodynamics ◽  
Equilibrium States ◽  
Variable Theory ◽  
Constrained Equilibrium ◽  
Flow Potential ◽  
Nonequilibrium States

This paper is concerned with infinitesimally constrained equilibrium states, which are nonequilibrium states and infinitesimally close to equilibrium states. The corresponding thermodynamics is established in this paper within the thermodynamic framework of Rice (1971, “Inelastic Constitutive Relations for Solids: An Internal Variable Theory and Its Application to Metal Plasticity,” J. Mech. Phys. Solids, 19, pp. 433–455). It is shown that the thermodynamics of infinitesimally constrained equilibrium states belongs to linear irreversible thermodynamics. The coefficient matrix is the Hessian matrix of the flow potential function at the equilibrium state. The process of a state change induced by an infinitesimal stress increment in time-independent plasticity can be viewed as a sequence of infinitesimally constrained equilibrium states. The thermodynamic counterpart of yield functions are flow potential functions, and their convexity is required by intrinsic dissipation inequality. Drucker and Il’yushin’s inequalities are not essential thermodynamic requirements.

Damage constitutive model of coal gangue concrete under freeze-thaw cycles

2020 ◽  
Vol 264 ◽  
pp. 120720
Author(s):  
Jisheng Qiu ◽  
Yunxian Zhou ◽  
Nikolay Ivanovich Vatin ◽  
Xiao Guan ◽  
Shukhrat Sultanov ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Coal Gangue ◽  
Freeze Thaw ◽  
Damage Constitutive Model

Study on Statistical Damage Constitutive Model of Rock Basing on Thermdynamics

2011 ◽  
Vol 217-218 ◽  
pp. 220-225
Author(s):  
Wen Lian Liu ◽  
Li De Wei
Keyword(s):  
Constitutive Model ◽  
Helmholtz Free Energy ◽  
Constitutive Relations ◽  
Experiment Data ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
Damage Constitutive Model ◽  
Strain Stress ◽  
Statistical Damage Constitutive Model ◽  
Set Up

Statistics models are effective to describe the relation of strain-stress of rock. But the constitutive relations in the statistical models are too simple for rock. Using the Eshelby equivalent inclusion method, a Helmholtz free energy for e damage rock is set up in the present paper. A constitutive model for damage rock is set up . The presented model is verified as reasonable and practical with comparion to the experiment data.

Sign in / Sign up

Export Citation Format

Share Document