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The thermomechanical coupling constitutive model of concrete is a critical subject for the theoretical investigation and numerical simulation of the mechanical behaviors of concrete members and structures at high temperature. This paper presents a thermomechanical coupling constitutive model for the description of the mechanical behaviors of concrete at different temperatures. The expression of the elastic strain increment is derived with the free energy function including the temperature variable. The expression of the plastic strain increment is derived from the yield function based on the Drucker–Prager strength criterion. The elastoplastic damage effect is included in this constitutive model. The damage variable is included in the yield function to consider the effect of the damage on the elastoplastic mechanical behaviors of concrete. The proposed constitutive model is validated by the comparison of the simulation results of the uniaxial compression tests of concrete at different temperatures with the corresponding test results. The simulation results accord well with the test results at different temperatures. This indicates that the proposed constitutive model can characterize the mechanical behaviors of concrete at different temperatures with considerable accuracy. The proposed constitutive model was applied to simulate an axially compressive concrete column. The simulation results are consistent with the essential mechanical response behaviors of concrete members at different temperatures.
Liang Li; Hongwei Wang; Jun Wu; Wenhua Jiang. A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage. Applied Sciences 2021, 11, 604 .
AMA StyleLiang Li, Hongwei Wang, Jun Wu, Wenhua Jiang. A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage. Applied Sciences. 2021; 11 (2):604.
Chicago/Turabian StyleLiang Li; Hongwei Wang; Jun Wu; Wenhua Jiang. 2021. "A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage." Applied Sciences 11, no. 2: 604.
An engineered cementitious composite (ECC) was reinforced with a steel grid and fibers to improve its tensile strength and ductility. A series of tensile tests have been carried out to investigate the quasi-static tensile capacity of the reinforced ECC. The quasi-static tensile capacities of reinforced ECCs with different numbers of steel-grid layers, types of fibers (Polyvinyl alcohol (PVA) fiber, KEVLAR fiber, and polyethylene (PE) fiber), and volume fractions of fibers have been tested and compared. It is indicated by the test results that: (1) On the whole, the steel grid-PVA fiber and steel grid-KEVLAR fiber reinforced ECCs have high tensile strength and considerable energy dissipation performance, while the steel grid-PE fiber reinforced ECC exhibits excellent ductility. (2) The ultimate tensile strength of the reinforced ECC can be improved by the addition of steel grids. The maximal peak tensile stress increase is about 50-95% or 140-190% by adding one layer or two layers of steel grid, respectively. (3) The ultimate tensile strength of the reinforced ECC can be enhanced with the increase of fiber volume fraction. For a certain kind of fiber, a volume fraction between 1.5% and 2% grants the reinforced ECC the best tensile strength. Near the ultimate loading point, the reinforced ECC exhibits strain hardening behavior, and its peak tensile stress increases considerably. The energy dissipation performance of the reinforced ECC can also be remarkably enhanced by such an increase in fiber volume fraction. (4) The ductility of the steel grid-PVA fiber reinforced ECC can be improved by the addition of steel grids and the increase of fiber volume fraction. The ductility of the steel grid-KEVLAR fiber reinforced ECC can be improved by the addition of steel grids alone. The ductility and energy dissipation performance of the steel grid-PE fiber reinforced ECC can be improved with the increase of fiber volume fraction alone. A mechanical model for the quasi-static initial and ultimate tensile strength of the steel grid-fiber reinforced ECC is proposed. The model is validated by the test data from the quasi-static tension experiments on the steel grid-PE fiber reinforced ECC.
Liang Li; Wenli Liu; Wu; Jun Wu; Wenjie Wu; Meng Wu; Li; Liu. Experimental Investigation on the Quasi-Static Tensile Capacity of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers. Materials 2019, 12, 2666 .
AMA StyleLiang Li, Wenli Liu, Wu, Jun Wu, Wenjie Wu, Meng Wu, Li, Liu. Experimental Investigation on the Quasi-Static Tensile Capacity of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers. Materials. 2019; 12 (17):2666.
Chicago/Turabian StyleLiang Li; Wenli Liu; Wu; Jun Wu; Wenjie Wu; Meng Wu; Li; Liu. 2019. "Experimental Investigation on the Quasi-Static Tensile Capacity of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers." Materials 12, no. 17: 2666.
The seismic response behavior of fluid-saturated porous media (FSPM) has been a critical subject in the area of soil dynamics and geotechnical earthquake engineering. In this paper, the numerical study of the seismic response of the FSPM is performed based on the u-p dynamic formulation. A time-stepping explicit algorithm for the numerical solution to the u-p dynamic formulation is developed. The precise time integration method is adopted in the algorithm to improve the computational accuracy. The transmitting artificial boundary is used to describe the energy radiative effect of the wave motion in the FSPM. The numerical results indicate that the time-stepping explicit algorithm developed in the current study is applicable and effective for the numerical solution of the dynamic problems of the FSPM based on the u-p dynamic formulation. Furthermore, parametric studies are performed to investigate the effect of the permeability coefficient, elastic modulus of the solid skeleton and porosity on the dynamic response of the FSPM. The analyses show that the permeability coefficient value has a negligible effect on the solid skeleton displacement but has a noticeable impact on the pore fluid pressure. With the decrease of the permeability coefficient value, the peak pore pressure increases remarkably. The elastic modulus of the solid skeleton has an important effect on the solid skeleton displacement and pore fluid pressure. With the decrease of the magnitude of elastic modulus, the solid skeleton displacement and pore fluid pressure increase remarkably. The porosity value has an insignificant effect on the solid skeleton displacement but has a significant impact on the pore fluid pressure. With the increase of the porosity value, the peak pore pressure decreases significantly.
Liang Li; Shuo Zhou; Xiuli Du; Jia Song; Chao Gao. Numerical Study on the Seismic Response of Fluid-Saturated Porous Media Using the Precise Time Integration Method. Applied Sciences 2019, 9, 2037 .
AMA StyleLiang Li, Shuo Zhou, Xiuli Du, Jia Song, Chao Gao. Numerical Study on the Seismic Response of Fluid-Saturated Porous Media Using the Precise Time Integration Method. Applied Sciences. 2019; 9 (10):2037.
Chicago/Turabian StyleLiang Li; Shuo Zhou; Xiuli Du; Jia Song; Chao Gao. 2019. "Numerical Study on the Seismic Response of Fluid-Saturated Porous Media Using the Precise Time Integration Method." Applied Sciences 9, no. 10: 2037.
In present paper, the numerical simulation is conducted to investigate the dynamic response of the composited pavement system under multiple drop weight impact loads. This composited pavement system consists of asphalt concrete (AC) layer reinforced with geogrid (GST), followed by high strength concrete (HSC) layer, and then engineered cementitious composites (ECC) layer, taking into account their relative advantages in terms of strength and relative ductility. Actual measurements from the laboratory test are used as a validation for the results of the numerical simulation. It is shown that the numerical results and laboratory measurements from two times of impact tests are in great accordance in terms of damage pattern, crater diameter, and potentiometer readings. This calibrated model from numerical simulation could then be further used to investigate the factors that might enhance the impact resistance of the composited pavement system subject to various levels of impact loads.
Jun Wu; Liang Li; Xiuli Du. Numerical Simulation on the Composited Pavement Slab Subjected to Multiple Drop Weight Impact. International Collaboration in Lifeline Earthquake Engineering 2016 2017, 1 .
AMA StyleJun Wu, Liang Li, Xiuli Du. Numerical Simulation on the Composited Pavement Slab Subjected to Multiple Drop Weight Impact. International Collaboration in Lifeline Earthquake Engineering 2016. 2017; ():1.
Chicago/Turabian StyleJun Wu; Liang Li; Xiuli Du. 2017. "Numerical Simulation on the Composited Pavement Slab Subjected to Multiple Drop Weight Impact." International Collaboration in Lifeline Earthquake Engineering 2016 , no. : 1.
The behaviour of an asphalt concrete structure subjected to severe loading, such as blast and impact loadings, is becoming critical for safety and anti-terrorist reasons. With the development of high-speed computational capabilities, it is possible to carry out the numerical simulation of an asphalt concrete structure subjected to blast or impact loading. In the simulation, the constitutive model plays a key role as the model defines the essential physical mechanisms of the material under different stress and loading conditions. In this paper, the key features of the Karagozian and Case concrete model (KCC) adopted in LSDYNA are evaluated and discussed. The formulations of the strength surfaces and the damage factor in the KCC model are verified. Both static and dynamic tests are used to determine the parameters of asphalt concrete in the KCC model. The modified damage factor is proposed to represent the higher failure strain that can improve the simulation of the behaviour of AC material. Furthermore, a series test of the asphalt concrete structure subjected to blast and impact loadings is conducted and simulated by using the KCC model. The simulation results are then compared with those from both field and laboratory tests. The results show that the use of the KCC model to simulate asphalt concrete structures can reproduce similar results as the field and laboratory test.
Jun Wu; Liang Li; Xiuli Du; Xuemei Liu. Numerical Study on the Asphalt Concrete Structure for Blast and Impact Load Using the Karagozian and Case Concrete Model. Applied Sciences 2017, 7, 202 .
AMA StyleJun Wu, Liang Li, Xiuli Du, Xuemei Liu. Numerical Study on the Asphalt Concrete Structure for Blast and Impact Load Using the Karagozian and Case Concrete Model. Applied Sciences. 2017; 7 (2):202.
Chicago/Turabian StyleJun Wu; Liang Li; Xiuli Du; Xuemei Liu. 2017. "Numerical Study on the Asphalt Concrete Structure for Blast and Impact Load Using the Karagozian and Case Concrete Model." Applied Sciences 7, no. 2: 202.
In order to describe the elasto-plastic dynamic response of fluid-saturated porous media, the incremental elasto-plastic wave propagation equations of fluid-saturated porous media are developed by the fundamental theory of continuum mechanics and appointing to the characteristic of fluid-saturated porous media. Then, the space discretization of these equations is performed to get their Galerkin formula. At last, the time discretization of this formula is carried out with the integral method which consists of central difference method and Newmark constant average acceleration method to get the explicit time integral formula for solving the wave propagation equations of porous media. On the basis of the integral formula mentioned above, the time-domain explicit finite element method is developed for calculation and analysis of the elasto-plastic dynamic response of fluid-saturated porous media. In this method, the decoupling technique is adopted and it does not need to solve simultaneous linear equations in each time step, so the computational effort and memory requirement can be reduced considerably by using this method.
Liang Li; Xiuli Du; Liyun Li; Chenggang Zhao. Explicit finite element method for calculation and analysis to the elasto-plastic dynamic response of fluid-saturated porous media. Frontiers of Architecture and Civil Engineering in China 2007, 1, 436 -442.
AMA StyleLiang Li, Xiuli Du, Liyun Li, Chenggang Zhao. Explicit finite element method for calculation and analysis to the elasto-plastic dynamic response of fluid-saturated porous media. Frontiers of Architecture and Civil Engineering in China. 2007; 1 (4):436-442.
Chicago/Turabian StyleLiang Li; Xiuli Du; Liyun Li; Chenggang Zhao. 2007. "Explicit finite element method for calculation and analysis to the elasto-plastic dynamic response of fluid-saturated porous media." Frontiers of Architecture and Civil Engineering in China 1, no. 4: 436-442.