Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensi...Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.展开更多
We study different types of projective synchronization （projective-anticipating, projective, and projectivelag synchronization） in a class of time-delayed chaotic systems related to optical bistable or hybrid optica...We study different types of projective synchronization （projective-anticipating, projective, and projectivelag synchronization） in a class of time-delayed chaotic systems related to optical bistable or hybrid optical bistable devices. We relax some limitations of previous work, where the scaling factor a can not be any desired value. In this paper, we achieve projective-anticipating, projective, and projective-lag synchronization without the limitation of a. A suitable controller is chosen using active control approach. Based on the Lyapunov stability theory, we derive the sufficient stability condition through theoretical analysis. The analytical results are validated by the numerical simulations using Ikeda model and Mackey-Glass model.展开更多
The performance of a digging shovel mainly depends on the style of the shovel, while the conventional experiment methods always suffer from the problems of high lost and long period. Aiming at these problems and the c...The performance of a digging shovel mainly depends on the style of the shovel, while the conventional experiment methods always suffer from the problems of high lost and long period. Aiming at these problems and the characteristic that soil is composed of countless small particles, dynamic simulation analysis was performed on the resistance to a bionic digging shovel and crushing rate of the soil during the normal working process of the bionic digging shovel by EDEM through numerical simulation, calculation and comparison. The results showed that compared with the ordinary shovel, the average drag-reducing rate in the X direction was 10.41%, and the average drag-reducing rate in the Y direction was 16.28%, and the soil crushing rate was improved by 2.67%. Therefore, the bionic digging shovel has certain superiority and extension value in structure and performance. Moreover, this analysis case fully demonstrates the unique advantage of DEM method and its generalizability, and provides certain reference for similar studies.展开更多
In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed u...In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed using numerical simulationmethod.The roadway's critical peak force wave and fracture region under dynamicwave action were put forward.It is concluded that the method has practical value to roadwaysupport and rockburst prevention.展开更多
Since computers and software have spread into all fields of industry, extensive efforts are currently made in order to improve the safety by applying certain numerical solutions. For many engineering problems involvin...Since computers and software have spread into all fields of industry, extensive efforts are currently made in order to improve the safety by applying certain numerical solutions. For many engineering problems involving shock and impact, there is no single ideal numerical method that can reproduce the various regimes of a problem. An approach wherein different techniques may be applied within a single numerical analysis can provide the ＂best＂ solution in terms of accuracy and efficiency. This paper presents a set of numerical simulations of ballistic tests which analyze the effects of soda lime glass laminates. The goal is to find an appropriate solver technique for simulating brittle materials and thereby improve bullet-proof glass to meet current challenges. To have the correct material model available is not enough. In this work, the main solver technologies are compared to create a perfect simulation model for soda lime glass laminates. The calculation should match ballistic trials and be used as the basis for further studies. These numerical simulations are performed with the nonlinear dynamic analysis computer code ANSYS AUTODYN.展开更多
This paper studies a three tier ecological food chain model consisting of nutrient,autotroph,and herbivore populations.Regeneration of nutrient from dead autotroph and herbivore biomass bydecomposers present in the so...This paper studies a three tier ecological food chain model consisting of nutrient,autotroph,and herbivore populations.Regeneration of nutrient from dead autotroph and herbivore biomass bydecomposers present in the soil is included.The time required for maturation of the herbivore populationis incorporated as a distributed time delay.Next,the authors introduce the time lag requiredfor regeneration of nutrient from the dead herbivore as a discrete time delay.Stability and bifurcationbehavior of the one-and two-delay models are carried out and a comparative study of the significanceof these delays in controlling the system dynamics is performed.Numerical simulations are done tojustify analytical results.展开更多
文摘Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.
基金Supported by Research Project of Hubei Provincial Department of Education under Grant No.Q20101609Foundation of Wuhan Textile University under Grant No.105040
文摘We study different types of projective synchronization （projective-anticipating, projective, and projectivelag synchronization） in a class of time-delayed chaotic systems related to optical bistable or hybrid optical bistable devices. We relax some limitations of previous work, where the scaling factor a can not be any desired value. In this paper, we achieve projective-anticipating, projective, and projective-lag synchronization without the limitation of a. A suitable controller is chosen using active control approach. Based on the Lyapunov stability theory, we derive the sufficient stability condition through theoretical analysis. The analytical results are validated by the numerical simulations using Ikeda model and Mackey-Glass model.
文摘The performance of a digging shovel mainly depends on the style of the shovel, while the conventional experiment methods always suffer from the problems of high lost and long period. Aiming at these problems and the characteristic that soil is composed of countless small particles, dynamic simulation analysis was performed on the resistance to a bionic digging shovel and crushing rate of the soil during the normal working process of the bionic digging shovel by EDEM through numerical simulation, calculation and comparison. The results showed that compared with the ordinary shovel, the average drag-reducing rate in the X direction was 10.41%, and the average drag-reducing rate in the Y direction was 16.28%, and the soil crushing rate was improved by 2.67%. Therefore, the bionic digging shovel has certain superiority and extension value in structure and performance. Moreover, this analysis case fully demonstrates the unique advantage of DEM method and its generalizability, and provides certain reference for similar studies.
基金Supported by the National Key Technology R&D Program in 11 th Five Years Plan of China(2006BAK03B06)
文摘In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed using numerical simulationmethod.The roadway's critical peak force wave and fracture region under dynamicwave action were put forward.It is concluded that the method has practical value to roadwaysupport and rockburst prevention.
文摘Since computers and software have spread into all fields of industry, extensive efforts are currently made in order to improve the safety by applying certain numerical solutions. For many engineering problems involving shock and impact, there is no single ideal numerical method that can reproduce the various regimes of a problem. An approach wherein different techniques may be applied within a single numerical analysis can provide the ＂best＂ solution in terms of accuracy and efficiency. This paper presents a set of numerical simulations of ballistic tests which analyze the effects of soda lime glass laminates. The goal is to find an appropriate solver technique for simulating brittle materials and thereby improve bullet-proof glass to meet current challenges. To have the correct material model available is not enough. In this work, the main solver technologies are compared to create a perfect simulation model for soda lime glass laminates. The calculation should match ballistic trials and be used as the basis for further studies. These numerical simulations are performed with the nonlinear dynamic analysis computer code ANSYS AUTODYN.
基金supported by the Department of Science and Technology, Ministry of Human Resource Development, Govt. of India under Grant No. SR/S4/MS:296/05
文摘This paper studies a three tier ecological food chain model consisting of nutrient,autotroph,and herbivore populations.Regeneration of nutrient from dead autotroph and herbivore biomass bydecomposers present in the soil is included.The time required for maturation of the herbivore populationis incorporated as a distributed time delay.Next,the authors introduce the time lag requiredfor regeneration of nutrient from the dead herbivore as a discrete time delay.Stability and bifurcationbehavior of the one-and two-delay models are carried out and a comparative study of the significanceof these delays in controlling the system dynamics is performed.Numerical simulations are done tojustify analytical results.
