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学者姓名:李亮
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Abstract :
The dynamic properties of concrete structures after being exposed to high temperatures play a crucial role in post-disaster repair and accident prevention measures. This study examined three different mixture ratios of Steel Fiber Reinforced Concrete (SFRC) with matrix strength of C60 and steel fiber contents of 0%, 1%, and 2%. A Split Hopkinson Pressure Bar (SHPB) with a diameter of 75 mm, along with a heating furnace, was employed to comprehensively investigate the dynamic compression behavior of materials. The specimens were exposed to temperatures ranging from 200 degrees C to 600 degrees C. In addition to evaluating the extent of mechanical degradation in SFRC after cooling, auxiliary impact experiments were also carried out at ambient temperature. The experimental data revealed that the dynamic peak stress and peak strain initially increased but eventually decreased as the loading rates continued to rise. The degree of strengthening, toughening, and energy absorption capacity of concrete materials progressively decreased as the escalation of strain rate after the cooling process. Moreover, the inclusion of steel fibers proved effective in preventing cracking and damage to the concrete, preserving the integrity of specimens even at higher temperatures. Simultaneously, the residual stress and deformation capacity of SFRC showed considerable enhancement after exposure to elevated temperatures.
Keyword :
Dynamic Increase Factor (DIF) Dynamic Increase Factor (DIF) Natural cooling after high temperatures Natural cooling after high temperatures Steel Fiber Reinforced Concrete (SRFC) Steel Fiber Reinforced Concrete (SRFC) Split Hopkinson Pressure Bar (SHPB) Split Hopkinson Pressure Bar (SHPB) Dynamic compressive performance Dynamic compressive performance
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GB/T 7714 | Li, Liang , Wang, Zichen , Wu, Jun et al. Comparative analysis of dynamic mechanical properties of steel fiber reinforced concrete under ambient temperature and after exposure to high temperatures [J]. | CASE STUDIES IN CONSTRUCTION MATERIALS , 2023 , 20 . |
MLA | Li, Liang et al. "Comparative analysis of dynamic mechanical properties of steel fiber reinforced concrete under ambient temperature and after exposure to high temperatures" . | CASE STUDIES IN CONSTRUCTION MATERIALS 20 (2023) . |
APA | Li, Liang , Wang, Zichen , Wu, Jun , Du, Xiuli , Wang, Hongwei , Liu, Wenli . Comparative analysis of dynamic mechanical properties of steel fiber reinforced concrete under ambient temperature and after exposure to high temperatures . | CASE STUDIES IN CONSTRUCTION MATERIALS , 2023 , 20 . |
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Abstract :
Bridge piers have a high risk of being attacked in wartime, which has the potential to trigger progressive bridge collapse. This study aims to predict the failure probability of reinforced con-crete (RC) piers exposed to military attack scenarios. Field explosion test and axial compression test were conducted to investigate the damage and post-blast performance of the RC pier first. Then, the uncertainties sourcing from the weapon accuracy were investigated. A performance -based (PB) vulnerability probabilistic assessment framework is developed which combines the Monte Carlo simulation (MCS) with a full-scale finite element (FE) model which was verified with test results. A probabilistic vulnerability assessment of a typical RC pier subjected to stochastic blast loading is conducted, and the vulnerability curve corresponding to three performance levels is developed. In addition, the damage modes and post-blast performance of the RC pier under blast loading are analyzed. Results show that the blast-induced damage to an RC pier had a significant influence on the axial bearing capacity, and the pier presents different damage modes at different scaled distances, which has a critical value of 0.65 m/kg1/3 between local and global damage modes. The failure probability of the pier corresponding to different performance levels increased with an increase in the TNT charge. The pier's probability of collapse is less than 20 % when the TNT charge weight does not exceed 500 kg.
Keyword :
Damage mode Damage mode Blast loads Blast loads Probabilistic vulnerability analysis Probabilistic vulnerability analysis Axial load bearing capacity Axial load bearing capacity Bridge pier Bridge pier
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GB/T 7714 | Lv, Chenxu , Yan, Qiushi , Li, Liang et al. Field test and probabilistic vulnerability assessment of a reinforced concrete bridge pier subjected to blast loads [J]. | ENGINEERING FAILURE ANALYSIS , 2023 , 143 . |
MLA | Lv, Chenxu et al. "Field test and probabilistic vulnerability assessment of a reinforced concrete bridge pier subjected to blast loads" . | ENGINEERING FAILURE ANALYSIS 143 (2023) . |
APA | Lv, Chenxu , Yan, Qiushi , Li, Liang , Li, Shutao . Field test and probabilistic vulnerability assessment of a reinforced concrete bridge pier subjected to blast loads . | ENGINEERING FAILURE ANALYSIS , 2023 , 143 . |
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Abstract :
本工作开展了钢网片-聚乙烯(PE)纤维增强水泥基复合材料的中低速动态拉伸性能试验研究,研究了其破坏状态、强度特性和能量吸收特性,并研究了纤维体积含量、钢网片层数和拉伸速率对其动态拉伸性能的影响。试验结果表明:PE纤维和钢网片的添加提高了水泥基复合材料的抗拉强度、变形能力与耗能能力。相对于基体材料,钢网片-PE纤维水泥基复合材料具有较为显著的增强和增韧效应。钢网片的主要作用是提高材料的抗拉强度,PE纤维的主要作用是提高材料的变形能力和耗能能力。纤维体积含量、钢网片层数和拉伸速率均对钢网片-PE纤维水泥基复合材料的动态拉伸性能有一定程度的影响。随着PE纤维体积含量的增加,材料的抗拉强度和耗能能力逐...
Keyword :
动态拉伸性能 动态拉伸性能 钢网片 钢网片 聚乙烯纤维 聚乙烯纤维 耗能能力 耗能能力 水泥基复合材料 水泥基复合材料
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GB/T 7714 | 李亮 , 栾贻恒 , 吴俊 et al. 钢网片-聚乙烯纤维增强水泥基复合材料中低速动态拉伸性能试验研究 [J]. | 材料导报 , 2022 , 36 (05) : 53-58 . |
MLA | 李亮 et al. "钢网片-聚乙烯纤维增强水泥基复合材料中低速动态拉伸性能试验研究" . | 材料导报 36 . 05 (2022) : 53-58 . |
APA | 李亮 , 栾贻恒 , 吴俊 , 杜修力 , 吴文杰 . 钢网片-聚乙烯纤维增强水泥基复合材料中低速动态拉伸性能试验研究 . | 材料导报 , 2022 , 36 (05) , 53-58 . |
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Abstract :
Near-field wave propagation of the fluid-saturated porous media (FSPM) is an important issue in soil dynamics and geotechnical earthquake engineering. In the current study, a fully explicit staggered algorithm for the near-field wave propagation analysis of the FSPM in the time domain is developed based on the u-p dynamic formulation. The decoupling of dynamic formulation is implemented by the diagonalization of the mass matrix and pore fluid compressibility matrix. The central difference method and Newmark constant average acceleration method are used for the solution of the displacement and velocity of solid skeleton, and the backward difference method is used for the solution of pore fluid pressure in the time domain. The effectiveness and feasibility of the matrix diagonalization are verified by the comparison with the classical numerical algorithm. The proposed algorithm is also validated by the comparison of the numerical results with the corresponding analytical solution results. Combing with the transmitting artificial boundary condition, the proposed algorithm is then applied to investigate the seismic response of a FSPM free field, and its applicability to the typical near-field wave propagation problems of the FSPM is indicated. The stability analysis of the proposed algorithm is finally conducted, and the corresponding stability criterion is presented. For the proposed algorithm, all the dynamic variables of the FSPM are solved in an iterative way and the coupling dynamic equations need not to be solved at each time step. The computational effort can be reduced considerably, and the computational efficiency can be improved remarkably.
Keyword :
fluid-saturated porous media fluid-saturated porous media fully explicit staggered algorithm fully explicit staggered algorithm u-p dynamic formulation u-p dynamic formulation near-field wave propagation near-field wave propagation dynamic response dynamic response transmitting artificial boundary condition transmitting artificial boundary condition
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GB/T 7714 | Li Liang , Xu Jingru , Du Xiuli et al. A fully explicit staggered algorithm for near-field wave propagation of fluid-saturated porous media based on u-p dynamic formulation [J]. | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2022 , 46 (18) : 3283-3309 . |
MLA | Li Liang et al. "A fully explicit staggered algorithm for near-field wave propagation of fluid-saturated porous media based on u-p dynamic formulation" . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS 46 . 18 (2022) : 3283-3309 . |
APA | Li Liang , Xu Jingru , Du Xiuli , Song Jia . A fully explicit staggered algorithm for near-field wave propagation of fluid-saturated porous media based on u-p dynamic formulation . | INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS , 2022 , 46 (18) , 3283-3309 . |
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Abstract :
Dynamic compressive tests of sand under passive confining pressure were carried out using a Split Hopkinson Pressure Bar (SHPB) setup. The dynamic response, energy dissipation and particle-breaking behaviors of sand subjected to high-speed impact were investigated. Sand specimens with moisture contents of 0%, 2%, 4%, 8%, 10% and 12% and relative densities of 0.1, 0.5 and 0.9 were prepared. The variation in the strain rate was controlled between 90 s(-1) and 500 s(-1). The specimens were confined in a designed sleeve to create passive confining pressure. The experimental results show that the sand specimens were extremely sensitive to the strain rate. When the strain rate was less than 400 s(-1), the stress and strain of the specimens increased with the increase in the strain rate but decreased when the strain rate exceeded 400 s(-1). The peak strain and peak stress increased with the increase in the relative density. Particle breakage was aggravated with the strain-rate increase. Compared with the specimen without water, the relative breakage rate of the specimen with a moisture content of 12% decreased by 30.53% when the strain rate was about 95 s(-1) and by 25.44% when the strain rate was about 460 s(-1). The analysis of energy dissipation revealed the essential cause of sand destruction. The specific energy absorption rate increased with the increases in the initial relative density and moisture content.
Keyword :
SHPB SHPB particle breakage particle breakage passive confining pressure passive confining pressure dynamic compressive behaviors dynamic compressive behaviors impact dynamic response impact dynamic response sand sand
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GB/T 7714 | Li, Liang , Kou, Xinyu , Zhang, Gao et al. Experimental Study on Dynamic Compressive Behaviors of Sand under Passive Confining Pressure [J]. | MATERIALS , 2022 , 15 (13) . |
MLA | Li, Liang et al. "Experimental Study on Dynamic Compressive Behaviors of Sand under Passive Confining Pressure" . | MATERIALS 15 . 13 (2022) . |
APA | Li, Liang , Kou, Xinyu , Zhang, Gao , Huang, Kewei . Experimental Study on Dynamic Compressive Behaviors of Sand under Passive Confining Pressure . | MATERIALS , 2022 , 15 (13) . |
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Abstract :
A finite element-thin layer element coupling method for the near-field wave propagation analysis in the fluid saturated porous media (FSPM) is developed based on the Biot u -U dynamic formulation. The case of the wave propagation normal to the boundary of calculating domain is investigated. The wave propagation equations are decoupled by the variables-separating method. The finite element method is adopted for the space discretization and numerical analysis of the finite domain, and the thin layer element method is applied to discretize the infinite domain and construct the consistent artificial boundary condition. This method is validated and then applied to the analysis to the near-field wave propagation problem of FSPM. Parametric sensitivity studies are conducted to analyze the effect of the mechanical parameters, including permeability coefficient, porosity, and Young's modulus of solid skeleton, on the dynamic response of FSPM. The study results indicate the effectiveness and efficiency of the developed method to the near-field wave propagation analysis in FSPM.
Keyword :
Finite element method Finite element method Fluid-saturated porous media Fluid-saturated porous media Thin layer element method Thin layer element method Variables-separating method Variables-separating method Consistent artificial boundary condition Consistent artificial boundary condition Near-field wave propagation Near-field wave propagation
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GB/T 7714 | Jiao, Hongyun , Li, Liang , Du, Xiuli et al. A finite element-thin layer element coupling method for near-field wave propagation in fluid-saturated porous media based on u-U dynamic formulation [J]. | SOIL DYNAMICS AND EARTHQUAKE ENGINEERING , 2022 , 158 . |
MLA | Jiao, Hongyun et al. "A finite element-thin layer element coupling method for near-field wave propagation in fluid-saturated porous media based on u-U dynamic formulation" . | SOIL DYNAMICS AND EARTHQUAKE ENGINEERING 158 (2022) . |
APA | Jiao, Hongyun , Li, Liang , Du, Xiuli , Shi, Peixin , Wang, Man . A finite element-thin layer element coupling method for near-field wave propagation in fluid-saturated porous media based on u-U dynamic formulation . | SOIL DYNAMICS AND EARTHQUAKE ENGINEERING , 2022 , 158 . |
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Abstract :
The permeability of saturated soils has great influence on the velocities and attenuation characteristics of fast compressional wave P1, low compressional wave P2, and shear wave S in saturated soils, respectively. In three different cases, namely zero, finite, and infinite permeability, the wave equations and theoretical velocities of P1, P2, and S wave in saturated soils are given based on the u-w-p equation, respectively. According to the solutions of the wave equations, the real velocities and attenuation coefficients of three waves are redefined, respectively. In different saturated soils, the influences of the permeability and the loading frequency on the wave velocities and attenuation are discussed, respectively. Moreover, the suitable application scope of the u-p equation is discussed based on different permeabilities and loading frequencies.
Keyword :
permeability permeability attenuation attenuation wave velocity wave velocity frequency dispersion frequency dispersion saturated porous media saturated porous media
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GB/T 7714 | Song, Jia , Xu, Chengshun , Li, Liang . The Influence of Permeability on the Propagation Characteristics of the Waves in Different Saturated Soils [J]. | APPLIED SCIENCES-BASEL , 2021 , 11 (17) . |
MLA | Song, Jia et al. "The Influence of Permeability on the Propagation Characteristics of the Waves in Different Saturated Soils" . | APPLIED SCIENCES-BASEL 11 . 17 (2021) . |
APA | Song, Jia , Xu, Chengshun , Li, Liang . The Influence of Permeability on the Propagation Characteristics of the Waves in Different Saturated Soils . | APPLIED SCIENCES-BASEL , 2021 , 11 (17) . |
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Abstract :
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.
Keyword :
concrete concrete thermomechanical coupling thermomechanical coupling thermodynamics thermodynamics constitutive model constitutive model elastoplastic damage elastoplastic damage
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GB/T 7714 | Li, Liang , Wang, Hongwei , Wu, Jun et al. A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage [J]. | APPLIED SCIENCES-BASEL , 2021 , 11 (2) . |
MLA | Li, Liang et al. "A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage" . | APPLIED SCIENCES-BASEL 11 . 2 (2021) . |
APA | Li, Liang , Wang, Hongwei , Wu, Jun , Jiang, Wenhua . A Thermomechanical Coupling Constitutive Model of Concrete Including Elastoplastic Damage . | APPLIED SCIENCES-BASEL , 2021 , 11 (2) . |
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Abstract :
Engineered cementitious composites (ECC) used as runway pavement material may suffer different strain rate loads such as aircraft taxiing, earthquakes, crash impacts, or blasts. In this paper, the dynamic tensile behaviors of the steel grid-polyvinyl alcohol (PVA) fiber and KEVLAR fiber-reinforced ECC were investigated by dynamic tensile tests at medium strain rates. The mixture was designed with different volume fractions of fibers and layer numbers of steel grids to explore the reinforcement effectiveness on the dynamic performance of the ECC. The volume fractions of these two types of fibers were 0%, 0.5%, 1%, 1.5%, and 2% of the ECC matrix, respectively. The layer numbers of the steel grid were 0, 1, and 2. The dynamic tensile behaviors of the PVA fiber and the KEVLAR fiber-reinforced ECC were also compared. The experimental results indicate that under dynamic tensile loads, the PVA-ECC reveals a ductile and multi-cracking failure behavior, and the KEVLAR-ECC displays a brittle failure behavior. The addition of the PVA fiber and the KEVLAR fiber can improve the tensile peak stress of the ECC matrix. For the specimens A0.5, A1, A1.5, and A2.0, the peak stress increases by 84.3%, 149.4%, 209.6%, and 237.3%, respectively, compared to the matrix specimen. For the specimens K0.5, K1, K1.5, and K2, the peak stress increases by about 72.3%, 147.0%, 195.2%, and 263.9%, respectively, compared to the matrix specimen. The optimum fiber volume content is 1.5% for the PVA-ECC and the KEVLAR-ECC. The KEVLAR-ECC can supply a higher tensile strength than the PVA-ECC, but the PVA-ECC reveals more prominent deformation capacity and energy dissipation performance than the KEVLAR-ECC. Embedding steel grid can improve the tensile peak stress and the energy dissipation of the ECC matrix. For the strain rate of 10(-3) s(-1), the peak stress of the A0.5S1 and A0.5S2 specimens increases by about 49.1% and 105.7% compared to the A0.5 specimen, and the peak stress of the K0.5S1 and K0.5S2 specimens increases by about 61.5% and 95.8%, respectively, compared to the K0.5 specimen.
Keyword :
strain rate strain rate engineered cementitious composites (ECC) engineered cementitious composites (ECC) KEVLAR fiber KEVLAR fiber dynamic tensile behavior dynamic tensile behavior PVA fiber PVA fiber steel grid steel grid
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GB/T 7714 | Li, Liang , Wang, Hongwei , Wu, Jun et al. Experimental Investigation on Dynamic Tensile Behaviors of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers [J]. | MATERIALS , 2021 , 14 (22) . |
MLA | Li, Liang et al. "Experimental Investigation on Dynamic Tensile Behaviors of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers" . | MATERIALS 14 . 22 (2021) . |
APA | Li, Liang , Wang, Hongwei , Wu, Jun , Li, Shutao , Wu, Wenjie . Experimental Investigation on Dynamic Tensile Behaviors of Engineered Cementitious Composites Reinforced with Steel Grid and Fibers . | MATERIALS , 2021 , 14 (22) . |
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Abstract :
The explicit numerical algorithm for the near-field wave motion of fluid-saturated porous media in time domain is investigated based on u-p dynamic formulation. The wave motion equations are decoupled, and dynamic coupling is eliminated by the diagonalization of the mass matrix and pore fluid compression matrix. Based on the decoupled wave motion equations, the central difference method and Newmark constant average acceleration method are adopted for the solution of solid-phase displacement and velocity, respectively. The formulation of pore fluid pressure is derived based on the backward difference method. Then the explicit staggered calculating formulas for the dynamic response of fluid-saturated porous media are derived, and a new full explicit numerical algorithm for the near-field wave motion of fluid-saturated porous media in time domain is developed. The rationality of matrix diagonalization in the algorithm is validated. The numerical results gained by the proposed algorithm accord well with the corresponding analytical results. This indicates the accuracy of the proposed algorithm. Combining the time domain numerical calculation method proposed with the transmission artificial boundary method, it is applied to the near field wave motion problem of fluid-saturated porous media, and the seismic response of saturated soil site is calculated and studied. The numerical results of the seismic response of saturated soil field accord with the elastic wave motion theory. This indicates the applicability of the developed algorithm to the near-field wave motion problem of fluid-saturated porous media. The stability characteristic of the developed algorithm is investigated based on the transfer matrix of the iterative calculating formulas of the algorithm. In the developed algorithm, all the variables of dynamic response are calculated in an iterative pattern. Thusly, this algorithm has the basic characteristic of the full explicit numerical algorithm in time domain. In the developed algorithm, all the components of the dynamic response are solved by recursive and iterative modes, which avoids solving the coupled dynamic equations. This developed algorithm has high computational efficiency and is an effective algorithm for solving near-field wave motion problems in fluid-saturated porous media in time domain. © 2020, Engineering Mechanics Press. All right reserved.
Keyword :
Computation theory Computation theory Seismic response Seismic response Transfer matrix method Transfer matrix method Iterative methods Iterative methods Elastic waves Elastic waves Numerical methods Numerical methods Equations of motion Equations of motion Porous materials Porous materials Computational efficiency Computational efficiency Time domain analysis Time domain analysis Dynamic response Dynamic response
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GB/T 7714 | Li, Liang , Li, Guo , Du, Xiu-Li et al. A full explicit numerical algorithm for near-field wave motion of fluid-saturated porous media in time domain [J]. | Engineering Mechanics , 2020 , 37 (8) : 20-31 . |
MLA | Li, Liang et al. "A full explicit numerical algorithm for near-field wave motion of fluid-saturated porous media in time domain" . | Engineering Mechanics 37 . 8 (2020) : 20-31 . |
APA | Li, Liang , Li, Guo , Du, Xiu-Li , Song, Jia . A full explicit numerical algorithm for near-field wave motion of fluid-saturated porous media in time domain . | Engineering Mechanics , 2020 , 37 (8) , 20-31 . |
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