The shakedown analysis of structures under variable multi-loadings is considered, and the corresponding simple shakedown condition is presented in this paper. Distribution of fixed stresses field is given, and the sel...The shakedown analysis of structures under variable multi-loadings is considered, and the corresponding simple shakedown condition is presented in this paper. Distribution of fixed stresses field is given, and the self-equilibrium of fixed stresses field is analyzed. Elastic shakedown and plastic shakedown conditions are presented based on the fixed stresses field. The theorem is convenient to evaluate the shakedown limit of structures under cyclical variable multiloadings through solving positive scalar fields and fixed stresses field factors at a series of dangerous positions of the structure, and tedious computations are avoided. Finally the theorem is applied to a thick-walled cylindrical tube under variable pressure and temperature, and the rolling contact problem. The results are in good agreement with some computational results.展开更多
Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benef...Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet(EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads.展开更多
In this paper,the load characteristics of shock wave,bubble pulsating water jet and cavitation closure are studied by carrying out underwater explosion experiments and numerical simulation of fixed square plates with ...In this paper,the load characteristics of shock wave,bubble pulsating water jet and cavitation closure are studied by carrying out underwater explosion experiments and numerical simulation of fixed square plates with 2.5,5 and 10 g trinitrotoluene.The results show that under the combined action of multiple loads,the impulse of bubble pulsation and water jet load plays a leading role in the process of underwater explosion,and the impulse of cavitation closure load is greater than that of shock wave.The damage to the structure cannot be ignored,and the pressure time-history curve presents a“multi-peak”state,and it is pointed out that the water jet is a concentrated load.Then,the dynamic response of the full-scale model of the ship under the combined action of multiple loads is studied,and the dynamic response of the ship under different cabin water depths and different explosion distances is discussed.The results show that when the ship is empty,the damage degree of the ship is the most serious,and the influence of cavitation effect on the half cabin is weaker than that of the empty cabin,so the damage degree is the second,and the damage degree is the smallest when the cabin is full.When the distance parameter is less than 0.68,the shock wave and the after flow play a leading role in the dynamic response of the ship.When the distance parameter is between 0.68 and 1.38,the combined action of the bubble pulsating water jet and the cavitation closure multi-load causes the main damage to the ship.When the distance parameter is greater than 1.38,the bubble pulsation and the cavitation closure load play a leading role.展开更多
Using an energy-based Hamiltonian function method,this paper investigates the robust excitation control of multi-machine multi-load power systems described by a set of uncertain differential algebraic equations.First,...Using an energy-based Hamiltonian function method,this paper investigates the robust excitation control of multi-machine multi-load power systems described by a set of uncertain differential algebraic equations.First,we complete the dissipative Hamiltonian realization of the power system and adjust its operating point by the means of pre-feedback control.Then,based on the obtained Hamiltonian realization,we discuss the robust excitation control of the power system and put forward an H1 excitation control strategy.Simulation results demonstrate the effectiveness of the control scheme.展开更多
As the main effective method of Wireless Power Transfer (WPT), Capacitive Power Transfer (CPT) has received extensive attention recently. For a CPT system, compensation topology is significant in improving system tran...As the main effective method of Wireless Power Transfer (WPT), Capacitive Power Transfer (CPT) has received extensive attention recently. For a CPT system, compensation topology is significant in improving system transfer power and controlling output characteristics. While the current research on multiple CPT systems only focus on the specific circuit, lacking systematic study on constant-voltage (CV) or constant-current (CC) output. This paper studies a general compensation topology model of a multiload CPT system based on CV and CC output characteristics. First, the general circuit model of primary and secondary compensation topology based on a T-type or ∏-type circuit is constructed with the coupler's simplified induced current source (ICS) model. A universal design method of the multiload CPT system is given. Then, according to the proposed theory, a multiload CPT system based on double-sided LCLC compensation topology is analyzed, achieving CC output, maximum coupler transfer power and zero phase angle between input voltage and input current. Lastly, an experimental setup of double loads CPT system with 500W &500W is carried out. When load resistance changes from 50 ohms to 100 ohms, maximum change rate of output current is 8.4 %, with rated output current of 2.5 A.展开更多
文摘The shakedown analysis of structures under variable multi-loadings is considered, and the corresponding simple shakedown condition is presented in this paper. Distribution of fixed stresses field is given, and the self-equilibrium of fixed stresses field is analyzed. Elastic shakedown and plastic shakedown conditions are presented based on the fixed stresses field. The theorem is convenient to evaluate the shakedown limit of structures under cyclical variable multiloadings through solving positive scalar fields and fixed stresses field factors at a series of dangerous positions of the structure, and tedious computations are avoided. Finally the theorem is applied to a thick-walled cylindrical tube under variable pressure and temperature, and the rolling contact problem. The results are in good agreement with some computational results.
基金supported by the State Grid Science and Technology Project, “Study on Multi-source and Multiload Coordination and Optimization Technology Considering Desalination of Sea Water” (No. SGTJDK00DWJS1800011)
文摘Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet(EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads.
基金supported by the National Natural Science Foundation of China(Grant No.12172178).
文摘In this paper,the load characteristics of shock wave,bubble pulsating water jet and cavitation closure are studied by carrying out underwater explosion experiments and numerical simulation of fixed square plates with 2.5,5 and 10 g trinitrotoluene.The results show that under the combined action of multiple loads,the impulse of bubble pulsation and water jet load plays a leading role in the process of underwater explosion,and the impulse of cavitation closure load is greater than that of shock wave.The damage to the structure cannot be ignored,and the pressure time-history curve presents a“multi-peak”state,and it is pointed out that the water jet is a concentrated load.Then,the dynamic response of the full-scale model of the ship under the combined action of multiple loads is studied,and the dynamic response of the ship under different cabin water depths and different explosion distances is discussed.The results show that when the ship is empty,the damage degree of the ship is the most serious,and the influence of cavitation effect on the half cabin is weaker than that of the empty cabin,so the damage degree is the second,and the damage degree is the smallest when the cabin is full.When the distance parameter is less than 0.68,the shock wave and the after flow play a leading role in the dynamic response of the ship.When the distance parameter is between 0.68 and 1.38,the combined action of the bubble pulsating water jet and the cavitation closure multi-load causes the main damage to the ship.When the distance parameter is greater than 1.38,the bubble pulsation and the cavitation closure load play a leading role.
基金supported by the National Natural Science Foundation of China(Grant No.60974005)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20094101120008)the Nature Science Foundation of Henan Province(No.092300410201).
文摘Using an energy-based Hamiltonian function method,this paper investigates the robust excitation control of multi-machine multi-load power systems described by a set of uncertain differential algebraic equations.First,we complete the dissipative Hamiltonian realization of the power system and adjust its operating point by the means of pre-feedback control.Then,based on the obtained Hamiltonian realization,we discuss the robust excitation control of the power system and put forward an H1 excitation control strategy.Simulation results demonstrate the effectiveness of the control scheme.
文摘As the main effective method of Wireless Power Transfer (WPT), Capacitive Power Transfer (CPT) has received extensive attention recently. For a CPT system, compensation topology is significant in improving system transfer power and controlling output characteristics. While the current research on multiple CPT systems only focus on the specific circuit, lacking systematic study on constant-voltage (CV) or constant-current (CC) output. This paper studies a general compensation topology model of a multiload CPT system based on CV and CC output characteristics. First, the general circuit model of primary and secondary compensation topology based on a T-type or ∏-type circuit is constructed with the coupler's simplified induced current source (ICS) model. A universal design method of the multiload CPT system is given. Then, according to the proposed theory, a multiload CPT system based on double-sided LCLC compensation topology is analyzed, achieving CC output, maximum coupler transfer power and zero phase angle between input voltage and input current. Lastly, an experimental setup of double loads CPT system with 500W &500W is carried out. When load resistance changes from 50 ohms to 100 ohms, maximum change rate of output current is 8.4 %, with rated output current of 2.5 A.
