Hot deformation behavior and microstructure evolution of hot isostatically pressed FGH96 P/M superalloy were studied using isothermal compression tests. The tests were performed on a Gleeble-1500 simulator in a temper...Hot deformation behavior and microstructure evolution of hot isostatically pressed FGH96 P/M superalloy were studied using isothermal compression tests. The tests were performed on a Gleeble-1500 simulator in a temperature range of 1000-1150 °C and strain rate of 0.001-1.0 s-1, respectively. By regression analysis of the stress—strain data, the constitutive equation for FGH96 superalloy was developed in the form of hyperbolic sine function with hot activation energy of 693.21 kJ/mol. By investigating the deformation microstructure, it is found that partial and full dynamical recrystallization occurs in specimens deformed below and above 1100 °C, respectively, and dynamical recrystallization （DRX） happens more readily with decreasing strain rate and increasing deformation temperature. Finally, equations representing the kinetics of DRX and grain size evolution were established.展开更多
This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster syste...This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster system with complicated and nonlinear characteristics, a non-linear information dynamics mode is introduced based on the maximum flux principle during modeling process to study the integrated risk assessment of complex disaster system. Based on the non-equilibrium statistical mechanics method, a stochastic evolution equation of this system is established. The integrated risk assessment of complex disaster system can be achieved by giving reasonable weights of each evaluation index to stabilize the system. The new model reveals the formation pattern of risk grade and the dynamics law of evolution. Meanwhile, a method is developed to solve the dynamics evolution equations of complex system through the self-organization feature map algorithm. The proposed method has been used in complex disaster integrated risk assessment for 31 provinces, cities and autonomous regions in China mainland. The results have indicated that the model is objective and effective.展开更多
A graph is introduced,which allows of a combinatorial interpretation of a discrete-timesemi-infinite Lotka-Volterra (dLV) equation.In particular,Hankel determinants used in a determinantsolution to the dLV equation ar...A graph is introduced,which allows of a combinatorial interpretation of a discrete-timesemi-infinite Lotka-Volterra (dLV) equation.In particular,Hankel determinants used in a determinantsolution to the dLV equation are evaluated,via the Gessel-Viennot method,in terms of non-intersectingsubgraphs.Further,the recurrence of the dLV equation describing its time-evolution is equivalentlyexpressed as a time-evolution of weight of specific subgraphs.展开更多
Great progress has been made in study on dynamic behavior of the damaged structures subject to deterministic excitation.The stochastic response analysis of the damaged structures,however,has not yet attracted people&#...Great progress has been made in study on dynamic behavior of the damaged structures subject to deterministic excitation.The stochastic response analysis of the damaged structures,however,has not yet attracted people's attention.Taking the damaged elastic beams for example,the analysis procedure for stochastic response of the damaged structures subject to stochastic excitations is investigated in this paper.First,the damage constitutive relations and the corresponding damage evolution equation of one-dimensional elastic structures are briefly discussed.Second,the stochastic dynamic equation with respect to transverse displacement of the damaged elastic beams is deduced.The finite difference method and Newmark method are adopted to solve the stochastic partially-differential equation and corresponding boundary conditions.The stochastic response characteristic,damage evolution law,the effect of noise intensity on damage evolution and the first-passage time of damage are discussed in detail.The present work extends the research field of damaged structures,and the proposed procedure can be generalized to analyze the dynamic behavior of more complex structures,such as damaged plates and shells.展开更多
文摘Hot deformation behavior and microstructure evolution of hot isostatically pressed FGH96 P/M superalloy were studied using isothermal compression tests. The tests were performed on a Gleeble-1500 simulator in a temperature range of 1000-1150 °C and strain rate of 0.001-1.0 s-1, respectively. By regression analysis of the stress—strain data, the constitutive equation for FGH96 superalloy was developed in the form of hyperbolic sine function with hot activation energy of 693.21 kJ/mol. By investigating the deformation microstructure, it is found that partial and full dynamical recrystallization occurs in specimens deformed below and above 1100 °C, respectively, and dynamical recrystallization （DRX） happens more readily with decreasing strain rate and increasing deformation temperature. Finally, equations representing the kinetics of DRX and grain size evolution were established.
基金supported by the National Twelfth Five-year Technology Support Projects of China (Grant Nos. 2009BAJ28B04, 2011BAK07B01,2011BAJ08B03, and 2011BAJ08B05)the National Natural Science Foundation of China (Grant No. 51208017)+1 种基金Beijing Postdoctoral Research Foundation (Grant No. 2012ZZ-17)China Postdoctoral Science Foundation Funded Project (Grant No. 2011M500199)
文摘This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster system with complicated and nonlinear characteristics, a non-linear information dynamics mode is introduced based on the maximum flux principle during modeling process to study the integrated risk assessment of complex disaster system. Based on the non-equilibrium statistical mechanics method, a stochastic evolution equation of this system is established. The integrated risk assessment of complex disaster system can be achieved by giving reasonable weights of each evaluation index to stabilize the system. The new model reveals the formation pattern of risk grade and the dynamics law of evolution. Meanwhile, a method is developed to solve the dynamics evolution equations of complex system through the self-organization feature map algorithm. The proposed method has been used in complex disaster integrated risk assessment for 31 provinces, cities and autonomous regions in China mainland. The results have indicated that the model is objective and effective.
文摘A graph is introduced,which allows of a combinatorial interpretation of a discrete-timesemi-infinite Lotka-Volterra (dLV) equation.In particular,Hankel determinants used in a determinantsolution to the dLV equation are evaluated,via the Gessel-Viennot method,in terms of non-intersectingsubgraphs.Further,the recurrence of the dLV equation describing its time-evolution is equivalentlyexpressed as a time-evolution of weight of specific subgraphs.
基金supported by the National Natural Science Foundation of China (Grant No. 11072076)
文摘Great progress has been made in study on dynamic behavior of the damaged structures subject to deterministic excitation.The stochastic response analysis of the damaged structures,however,has not yet attracted people's attention.Taking the damaged elastic beams for example,the analysis procedure for stochastic response of the damaged structures subject to stochastic excitations is investigated in this paper.First,the damage constitutive relations and the corresponding damage evolution equation of one-dimensional elastic structures are briefly discussed.Second,the stochastic dynamic equation with respect to transverse displacement of the damaged elastic beams is deduced.The finite difference method and Newmark method are adopted to solve the stochastic partially-differential equation and corresponding boundary conditions.The stochastic response characteristic,damage evolution law,the effect of noise intensity on damage evolution and the first-passage time of damage are discussed in detail.The present work extends the research field of damaged structures,and the proposed procedure can be generalized to analyze the dynamic behavior of more complex structures,such as damaged plates and shells.
