Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is ...Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete semantics.Hence, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.展开更多
A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic ...A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic equilibrium. As many as 21 elements (Cu. S, Fe. Ni, Co. Sn, As, Sb. Bi, Ph. Zn.An. Ag. O, N, C, H, Ca, Mg, Al, and St) and 73 compounds are considered. This model accounts forphysical entrainment in the melts. The predictions by the present computer model are compared with theknown commercial data from Guixi Smelter in China, Home Smelter in Canada and Naoshima Smelter inJapan. The agreements between the computer predictions and the commercial data are excellent, so that thepresent computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.展开更多
A three-dimensional(3D) lattice model for predicting the rheological behavior of asphalt mixtures was presented.In this model asphalt mixtures were described as a two-phase composite material consisting of asphalt san...A three-dimensional(3D) lattice model for predicting the rheological behavior of asphalt mixtures was presented.In this model asphalt mixtures were described as a two-phase composite material consisting of asphalt sand and coarse aggregates distributed randomly.Asphalt sand was regarded as a viscoelastic material and aggregates as an elastic material.The rheological response of asphalt mixture subjected to different constant stresses was simulated.The calibrated overall creep strain shows a good approximation to experimental results.展开更多
An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex...An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex envelope signal for description of the envelope memory effect. Using traditional one and two-tone tests, the coefficients of nonlinear model and the FIR filter can be extracted. At last the model has been applied to a 10 W WCDMA Power amplifier to predict its output signal. And simulation results show that the model output conforms very well to the traditional transistor level simulation results.展开更多
The original descriptive model of shear stress and shear displacement only reflects the stress deformation characteristics of plastic structural plane.The index model was revised and piecewise index model was built to...The original descriptive model of shear stress and shear displacement only reflects the stress deformation characteristics of plastic structural plane.The index model was revised and piecewise index model was built to describe the stress deformation characteristics of plastic structural plane and brittle structural plane.The relation of stress and strain to the failure mode of structural plane considering the effect of its shape was investigated,and a model which could reflect the relation between undulate angle and shear strength was built.The result indicates that structural plane presents nonlinear characteristics,specifically,the value of undulate angle,as well as corresponding shear strength,becomes larger as the normal stress decreases.展开更多
The fracture behavior of polymer-bonded explosive(PBX) seriously affects the safety and reliability of weapon system.The effects of interface debonding and initial meso-damage on the fracture behavior of PBX under qua...The fracture behavior of polymer-bonded explosive(PBX) seriously affects the safety and reliability of weapon system.The effects of interface debonding and initial meso-damage on the fracture behavior of PBX under quasi-static tension are studied using numerical method.A twodimensional representative volume element(RVE) is established based on Voronoi model in which the component contents could be regulated and the particles are randomly distributed.A nonlinear damage model of polymer matrix relative to matrix depth between particles is constructed.The results show that the simulated strain-stress relation is coincident with experiment data.It is found that interface debonding leads to the nucleation and propagation of meso-cracks,and a main crack approximately perpendicular to the loading direction is generated finally.The interface debonding tends to occur in the interface perpendicular to the loading direction.There seems to be a phenomenon that strain softening and hardening alternatively appear around peak stress of stress and strain curve.It is shown that the initial damages of intragranular and interfacial cracks both decrease the modulus and failure stress,and the main crack tends to propagate toward the initial meso-cracks.展开更多
The downward moving behavior of pellets in a 8 m2 pellet shaft furnace with an internal vertical air channel and a drying bed was studied by means of a visualized model(1-15) and a top model(1-1).The visualized model ...The downward moving behavior of pellets in a 8 m2 pellet shaft furnace with an internal vertical air channel and a drying bed was studied by means of a visualized model(1-15) and a top model(1-1).The visualized model experiment shows that the downward movement of pellets can be regarded as plug flow approximately inside the furnace except for the lower region of cooling zone due to the influence of the drained hopper.The top model experiment reveals that the pellet sizes increase along the moving direction because of the percolation phenomenon,which results in a decrease of the resistance coefficient and an increase of the gas flow rate from the furnace wall toward the furnace center.展开更多
基金This work was supported by the National Natural Science Foundation of China(62003359).
文摘Today’s air combat has reached a high level of uncertainty where continuous or discrete variables with crisp values cannot be properly represented using fuzzy sets. With a set of membership functions, fuzzy logic is well-suited to tackle such complex states and actions. However, it is not necessary to fuzzify the variables that have definite discrete semantics.Hence, the aim of this study is to improve the level of model abstraction by proposing multiple levels of cascaded hierarchical structures from the perspective of function, namely, the functional decision tree. This method is developed to represent behavioral modeling of air combat systems, and its metamodel,execution mechanism, and code generation can provide a sound basis for function-based behavioral modeling. As a proof of concept, an air combat simulation is developed to validate this method and the results show that the fighter Alpha built using the proposed framework provides better performance than that using default scripts.
文摘A computer model has been developed to simulate the distribution behaviors of Ni, Co. Sn. Ph,Zn, As, Sb, Bi, An and Ag in copper smelting process. The model assumes that the copper smelting furnaceis in thermodynamic equilibrium. As many as 21 elements (Cu. S, Fe. Ni, Co. Sn, As, Sb. Bi, Ph. Zn.An. Ag. O, N, C, H, Ca, Mg, Al, and St) and 73 compounds are considered. This model accounts forphysical entrainment in the melts. The predictions by the present computer model are compared with theknown commercial data from Guixi Smelter in China, Home Smelter in Canada and Naoshima Smelter inJapan. The agreements between the computer predictions and the commercial data are excellent, so that thepresent computer model can be used to monitor and optimize the actual industrial operations of copper smelting. It is applicable to simulation of almost all copper pyrometallurgical processes.
基金Project(10672063) supported by the National Natural Science Foundation of China
文摘A three-dimensional(3D) lattice model for predicting the rheological behavior of asphalt mixtures was presented.In this model asphalt mixtures were described as a two-phase composite material consisting of asphalt sand and coarse aggregates distributed randomly.Asphalt sand was regarded as a viscoelastic material and aggregates as an elastic material.The rheological response of asphalt mixture subjected to different constant stresses was simulated.The calibrated overall creep strain shows a good approximation to experimental results.
文摘An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex envelope signal for description of the envelope memory effect. Using traditional one and two-tone tests, the coefficients of nonlinear model and the FIR filter can be extracted. At last the model has been applied to a 10 W WCDMA Power amplifier to predict its output signal. And simulation results show that the model output conforms very well to the traditional transistor level simulation results.
基金Project(50878212) supported by National Natural Science Foundation of ChinaProject(1298011-2) supported by the Funding of Scientific Research and Technology Development Projects of Guangxi Province,China+2 种基金Project(12JJ6052) supported by Natural Science Foundation of Hunan Province,ChinaProject(kfj120402) supported Open Fund of Key Laboratory of Special Environment Road Engineering of Hunan Province(Changsha University of Science&Technology),ChinaProject(13C1010) supported by the Research Foundation of Education Bureau of Hunan Province,China
文摘The original descriptive model of shear stress and shear displacement only reflects the stress deformation characteristics of plastic structural plane.The index model was revised and piecewise index model was built to describe the stress deformation characteristics of plastic structural plane and brittle structural plane.The relation of stress and strain to the failure mode of structural plane considering the effect of its shape was investigated,and a model which could reflect the relation between undulate angle and shear strength was built.The result indicates that structural plane presents nonlinear characteristics,specifically,the value of undulate angle,as well as corresponding shear strength,becomes larger as the normal stress decreases.
文摘The fracture behavior of polymer-bonded explosive(PBX) seriously affects the safety and reliability of weapon system.The effects of interface debonding and initial meso-damage on the fracture behavior of PBX under quasi-static tension are studied using numerical method.A twodimensional representative volume element(RVE) is established based on Voronoi model in which the component contents could be regulated and the particles are randomly distributed.A nonlinear damage model of polymer matrix relative to matrix depth between particles is constructed.The results show that the simulated strain-stress relation is coincident with experiment data.It is found that interface debonding leads to the nucleation and propagation of meso-cracks,and a main crack approximately perpendicular to the loading direction is generated finally.The interface debonding tends to occur in the interface perpendicular to the loading direction.There seems to be a phenomenon that strain softening and hardening alternatively appear around peak stress of stress and strain curve.It is shown that the initial damages of intragranular and interfacial cracks both decrease the modulus and failure stress,and the main crack tends to propagate toward the initial meso-cracks.
基金Projects(59374166,58974155) supported by the National Natural Science Foundation of China
文摘The downward moving behavior of pellets in a 8 m2 pellet shaft furnace with an internal vertical air channel and a drying bed was studied by means of a visualized model(1-15) and a top model(1-1).The visualized model experiment shows that the downward movement of pellets can be regarded as plug flow approximately inside the furnace except for the lower region of cooling zone due to the influence of the drained hopper.The top model experiment reveals that the pellet sizes increase along the moving direction because of the percolation phenomenon,which results in a decrease of the resistance coefficient and an increase of the gas flow rate from the furnace wall toward the furnace center.
