In order to investigate the fatigue behavior of asphalt concrete, a new numerical approach based on a bi-linear cohesive zone model （CZM） is developed. Integrated with the CZM, a fatigue damage evolution model is es...In order to investigate the fatigue behavior of asphalt concrete, a new numerical approach based on a bi-linear cohesive zone model （CZM） is developed. Integrated with the CZM, a fatigue damage evolution model is established to indicate the gradual degradation of cohesive properties of asphalt concrete under cyclic loading. Then the model is implemented in the finite element software ABAQUS through a user-defined subroutine. Based on the proposed model, an indirect tensile fatigue test is finally simulated. The fatigue lives obtained through numerical analysis show good agreement with laboratory results. Fatigue damage accumulates in a nonlinear manner during the cyclic loading process and damage initiation phase is the major part of fatigue failure. As the stress ratio increases, the time of the steady damage growth stage decreases significantly. It is found that the proposed fatigue damage evolution model can serve as an accurate and efficient tool for the prediction of fatigue damage of asphalt concrete.展开更多
Pre-stressed bolt anchorage is the key technology for jointed rock masses in rock tunnelling,slope treatment and mining engineering.To investigate the mechanical properties and reinforcement effect of jointed rock mas...Pre-stressed bolt anchorage is the key technology for jointed rock masses in rock tunnelling,slope treatment and mining engineering.To investigate the mechanical properties and reinforcement effect of jointed rock masses with pre-stressed bolts,in this study,uniaxial compression tests were conducted on specimens with different anchoring types and flaw inclination angles.ABAQUS software was used to verify and supplement the laboratory tests.The laws of the uniaxial compressive strength(UCS)obtained from the numerical simulations and laboratory tests were consistent.The results showed that under the same flaw angle,both the UCS and elastic modulus of the bolted specimens were improved compared with those of the specimens without bolts and the improvements increased with an increase in the bolt pre-stress.Under the same anchoring type,the UCS and elastic modulus of the jointed specimens increased with an increase in the flaw angle.The pre-stressed bolt could not only restrain the slip of the specimens along the flaw surface but also change the propagation mode of the secondary cracks and limit the initiation of cracks.In addition,the plot contours of the maximum principal strain and the Tresca stress of the numerical models were influenced by the anchoring type,flaw angle,anchoring angle and bolt position.展开更多
The environmental impact caused by local people （ecological footprint of consumption, EFc） and the actual environmental impact that the ecosystem burdens （ecological footprint of production, EFp） in West Jilin Pro...The environmental impact caused by local people （ecological footprint of consumption, EFc） and the actual environmental impact that the ecosystem burdens （ecological footprint of production, EFp） in West Jilin Province, Northeast China from 1986 to 2006 were evaluated by using ecological footprint （EF） method. And the major driving forces of EFc and EFp were analyzed by STIRPAT model. Both EFc and EFp showed increasing trends in 1986-2006, accompanied by decreasing ecological deficits but expanding ecological overshoots. Population （P）, GDP per capita （A1）, quadratic term of GDP per capita （A2）, urbanization （Tα1）, and quadratic term of urbanization （Ta2） were important influencing factors of EFc, among which Tα2 and Tα1 were the most dominate driving forces of EFc. A1, A2 and Tα2 were important influencing factors of EFp, among which A2 and A1 were the most dominate driving forces of EFp. In 1986-2006, the classical Environmental Kuznets Curve hypothesis did not exist between A2 and EF （both EFc and EFp）, but did between Tα2 and EF. The results indicate that enhancing the urbanization process and diversifying economic sources is one of the most effective ways to reduce the environmental impact of West Jilin Province. Moreover, importance should be attached to improve the eco-efficiency of resource exploitation and consumption.展开更多
In this paper, the dislocation of industrial structure refers to the inconsisency benveen employment structure and output structure in three industrles. Dnring the past over ten years, with the development of the Thre...In this paper, the dislocation of industrial structure refers to the inconsisency benveen employment structure and output structure in three industrles. Dnring the past over ten years, with the development of the Three Gorges regional social and economic, the industrial structure has optimized and upgraded constantly. However, for kinds of reasons, employment structure transference has lagged far behind output structure transference. In This paper, we try to analyze the causes of dislocation of the Three Gorges Regional industrial structure in analytical method of dislocation of industrial structure, and put forward the fundamental measures to optimize industrial stracture and promote sustainable development of the regional economy.展开更多
Based on the methodology provided by Organization for Economic Co-operation and Development,we analyze regional disparities in China's mainland at provincial level between 2000 and 2005.It regards regional GDP gro...Based on the methodology provided by Organization for Economic Co-operation and Development,we analyze regional disparities in China's mainland at provincial level between 2000 and 2005.It regards regional GDP growth as the joint result of contribution of a number of factors,i.e.capital productivity,capital per manpower,specialization,employment rate,active population,and population.The results show that for all provincial units,capital per manpower is a dominant contributing factor to the growth of GDP per capita during the period from 2000 to 2005 while capital productivity has quite significant negative impacts.Specialization contributes differently in different provinces.In most provincial units,employment rate and age activity have a positive impact on growth of GDP per capita,though not very significantly.展开更多
A series of 2D direct numerical simulations were performed with an accurate level set method for single drop impacts.The adopted ACLS method was validated to be efficient with perfect mass conservation in both normal ...A series of 2D direct numerical simulations were performed with an accurate level set method for single drop impacts.The adopted ACLS method was validated to be efficient with perfect mass conservation in both normal and oblique impacts.A square-root correction for neck bases was modified in accuracy as well as scope of applications.In addition,process of jet formation and evolution was studied to reveal internal dynamics in drop impacts.It's found that pressure gradient and vortex are coexisting and completive reasons for jet topology while the inclined angle has a significant effect on them.Mechanisms of jet formation and evolution are different in the front and back necks.With the help of PDF distribution and correction calculation,a compromise in the competition is observed.This work lays a solid foundation for further studies of dynamics in gas-liquid flows.展开更多
A comprehensive study on various internal energies for the dipolar hard sphere fluids, including Stockmayer fluids, the mixtures of Lennard-Jones and Stockmayer and Stockmayer fluids and the electrolyte solutions is r...A comprehensive study on various internal energies for the dipolar hard sphere fluids, including Stockmayer fluids, the mixtures of Lennard-Jones and Stockmayer and Stockmayer fluids and the electrolyte solutions is reported based on the perturbation theory and mean spherical approximation. Compared with the results of molecular simulations, it is shown that the perturbation theory is better than the mean spherical approximation.展开更多
Do Eurozone＇s countries converge or diverge over time？ In this paper, the issue of the Eurozone cohesion is analyzed, with emphasis on the North-South axis. The dynamics of 10 economic variables covered the general ...Do Eurozone＇s countries converge or diverge over time？ In this paper, the issue of the Eurozone cohesion is analyzed, with emphasis on the North-South axis. The dynamics of 10 economic variables covered the general performance （GDP, consumption）, price environment （prices and interest rates）, both public and private financial variables and competitiveness （real effective exchange rates, unit labor costs etc.）. The complex analysis of the data indicates that whereas in the most of analyzed variables neither convergence nor divergence can be identified, in the all important competitiveness area the long term divergence between the North and the South of the Eurozone is undeniable. Unless addressed, this dynamics may constitute significant, and perhaps ultimate, threats to the Eurozone cohesion and perhaps to its existence.展开更多
基金The Open Research Fund of Key Laboratory of Highway Engineering of Sichuan Province of Southw est Jiaotong University (No.LHTE002201102)
文摘In order to investigate the fatigue behavior of asphalt concrete, a new numerical approach based on a bi-linear cohesive zone model （CZM） is developed. Integrated with the CZM, a fatigue damage evolution model is established to indicate the gradual degradation of cohesive properties of asphalt concrete under cyclic loading. Then the model is implemented in the finite element software ABAQUS through a user-defined subroutine. Based on the proposed model, an indirect tensile fatigue test is finally simulated. The fatigue lives obtained through numerical analysis show good agreement with laboratory results. Fatigue damage accumulates in a nonlinear manner during the cyclic loading process and damage initiation phase is the major part of fatigue failure. As the stress ratio increases, the time of the steady damage growth stage decreases significantly. It is found that the proposed fatigue damage evolution model can serve as an accurate and efficient tool for the prediction of fatigue damage of asphalt concrete.
基金Project(51979281)supported by the National Natural Science Foundation of ChinaProject(ZR2018MEE050)supported by the Natural Science Foundation of Shandong Province,ChinaProject(18CX02079A)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Pre-stressed bolt anchorage is the key technology for jointed rock masses in rock tunnelling,slope treatment and mining engineering.To investigate the mechanical properties and reinforcement effect of jointed rock masses with pre-stressed bolts,in this study,uniaxial compression tests were conducted on specimens with different anchoring types and flaw inclination angles.ABAQUS software was used to verify and supplement the laboratory tests.The laws of the uniaxial compressive strength(UCS)obtained from the numerical simulations and laboratory tests were consistent.The results showed that under the same flaw angle,both the UCS and elastic modulus of the bolted specimens were improved compared with those of the specimens without bolts and the improvements increased with an increase in the bolt pre-stress.Under the same anchoring type,the UCS and elastic modulus of the jointed specimens increased with an increase in the flaw angle.The pre-stressed bolt could not only restrain the slip of the specimens along the flaw surface but also change the propagation mode of the secondary cracks and limit the initiation of cracks.In addition,the plot contours of the maximum principal strain and the Tresca stress of the numerical models were influenced by the anchoring type,flaw angle,anchoring angle and bolt position.
基金Under the auspices of Major State Basic Research Development Program of China(No.2004CB418507)
文摘The environmental impact caused by local people （ecological footprint of consumption, EFc） and the actual environmental impact that the ecosystem burdens （ecological footprint of production, EFp） in West Jilin Province, Northeast China from 1986 to 2006 were evaluated by using ecological footprint （EF） method. And the major driving forces of EFc and EFp were analyzed by STIRPAT model. Both EFc and EFp showed increasing trends in 1986-2006, accompanied by decreasing ecological deficits but expanding ecological overshoots. Population （P）, GDP per capita （A1）, quadratic term of GDP per capita （A2）, urbanization （Tα1）, and quadratic term of urbanization （Ta2） were important influencing factors of EFc, among which Tα2 and Tα1 were the most dominate driving forces of EFc. A1, A2 and Tα2 were important influencing factors of EFp, among which A2 and A1 were the most dominate driving forces of EFp. In 1986-2006, the classical Environmental Kuznets Curve hypothesis did not exist between A2 and EF （both EFc and EFp）, but did between Tα2 and EF. The results indicate that enhancing the urbanization process and diversifying economic sources is one of the most effective ways to reduce the environmental impact of West Jilin Province. Moreover, importance should be attached to improve the eco-efficiency of resource exploitation and consumption.
文摘In this paper, the dislocation of industrial structure refers to the inconsisency benveen employment structure and output structure in three industrles. Dnring the past over ten years, with the development of the Three Gorges regional social and economic, the industrial structure has optimized and upgraded constantly. However, for kinds of reasons, employment structure transference has lagged far behind output structure transference. In This paper, we try to analyze the causes of dislocation of the Three Gorges Regional industrial structure in analytical method of dislocation of industrial structure, and put forward the fundamental measures to optimize industrial stracture and promote sustainable development of the regional economy.
文摘Based on the methodology provided by Organization for Economic Co-operation and Development,we analyze regional disparities in China's mainland at provincial level between 2000 and 2005.It regards regional GDP growth as the joint result of contribution of a number of factors,i.e.capital productivity,capital per manpower,specialization,employment rate,active population,and population.The results show that for all provincial units,capital per manpower is a dominant contributing factor to the growth of GDP per capita during the period from 2000 to 2005 while capital productivity has quite significant negative impacts.Specialization contributes differently in different provinces.In most provincial units,employment rate and age activity have a positive impact on growth of GDP per capita,though not very significantly.
基金Supported by the National Natural Science Foundation of China(91541202,51276163)
文摘A series of 2D direct numerical simulations were performed with an accurate level set method for single drop impacts.The adopted ACLS method was validated to be efficient with perfect mass conservation in both normal and oblique impacts.A square-root correction for neck bases was modified in accuracy as well as scope of applications.In addition,process of jet formation and evolution was studied to reveal internal dynamics in drop impacts.It's found that pressure gradient and vortex are coexisting and completive reasons for jet topology while the inclined angle has a significant effect on them.Mechanisms of jet formation and evolution are different in the front and back necks.With the help of PDF distribution and correction calculation,a compromise in the competition is observed.This work lays a solid foundation for further studies of dynamics in gas-liquid flows.
基金Supported by the National Natural Science Foundation of China(No.29576250).
文摘A comprehensive study on various internal energies for the dipolar hard sphere fluids, including Stockmayer fluids, the mixtures of Lennard-Jones and Stockmayer and Stockmayer fluids and the electrolyte solutions is reported based on the perturbation theory and mean spherical approximation. Compared with the results of molecular simulations, it is shown that the perturbation theory is better than the mean spherical approximation.
文摘Do Eurozone＇s countries converge or diverge over time？ In this paper, the issue of the Eurozone cohesion is analyzed, with emphasis on the North-South axis. The dynamics of 10 economic variables covered the general performance （GDP, consumption）, price environment （prices and interest rates）, both public and private financial variables and competitiveness （real effective exchange rates, unit labor costs etc.）. The complex analysis of the data indicates that whereas in the most of analyzed variables neither convergence nor divergence can be identified, in the all important competitiveness area the long term divergence between the North and the South of the Eurozone is undeniable. Unless addressed, this dynamics may constitute significant, and perhaps ultimate, threats to the Eurozone cohesion and perhaps to its existence.
