Composite penalty method of a low order anisotropic nonconforming quadrilateral finite element for the Stokes problem is presented. This method with a large penalty parameter can achieve the same accuracy as the stand...Composite penalty method of a low order anisotropic nonconforming quadrilateral finite element for the Stokes problem is presented. This method with a large penalty parameter can achieve the same accuracy as the stand method with a small penalty parameter and the convergence rate of this method is two times as that of the standard method under the condition of the same order penalty parameter. The superconvergence for velocity is established as well. The results of this paper are also valid to the most of the known nonconforming finite element methods.展开更多
This paper presents a parallel composite local search algorithm based on multiple search neighborhoods to solve a special kind of timetable problem. The new algorithm can also effectively solve those problems that can...This paper presents a parallel composite local search algorithm based on multiple search neighborhoods to solve a special kind of timetable problem. The new algorithm can also effectively solve those problems that can be solved by general local search algorithms. Experimental results show that the new algorithm can generate better solutions than general local search algorithms.展开更多
This article introduces a fleet composition algorithm for a fleet of intermediate carriers, which should deliver a swarm of miniature unmanned aerial vehicles （mini-UAVs） to a mission area. The algorithm is based on...This article introduces a fleet composition algorithm for a fleet of intermediate carriers, which should deliver a swarm of miniature unmanned aerial vehicles （mini-UAVs） to a mission area. The algorithm is based on the sequential solution of several knapsack problems with various constraints. The algorithm allows both to form an initial set of required types of intermediate carriers, and to generate a fleet of intermediate carriers. The formation of a fleet of intermediate carriers to solve a suppression of enemy air defense （SEAD） problem is presented to illustrate the proposed algorithm.展开更多
Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of linear problems are difficult to be managed by the theoreti...Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of linear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an effective tool to investigate the nonlinear problems.展开更多
In this paper,we generalize the direct method of lines for linear elasticity problems of composite materials in star-shaped domains and consider its application to inverse elasticity problems.We assume that the bounda...In this paper,we generalize the direct method of lines for linear elasticity problems of composite materials in star-shaped domains and consider its application to inverse elasticity problems.We assume that the boundary of the star-shaped domain can be described by an explicit C 1 parametric curve in the polar coordinate.We introduce the curvilinear coordinate,in which the irregular star-shaped domain is converted to a regular semi-infinite strip.The equations of linear elasticity are discretized with respect to the angular variable and we solve the resulting semidiscrete approximation analytically using a direct method.The eigenvalues of the semi-discrete approximation converge quickly to the true eigenvalues of the elliptic operator,which helps capture the singularities naturally.Moreover,an optimal error estimate of our method is given.For the inverse elasticity problems,we determine the Lam´e coefficients from measurement data by minimizing a regularized energy functional.We apply the direct method of lines as the forward solver in order to cope with the irregularity of the domain and possible singularities in the forward solutions.Several numerical examples are presented to show the effectiveness and accuracy of our method for both forward and inverse elasticity problems of composite materials.展开更多
An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective f...An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective function contained several local optima and globaloptimality could not be ensured by all the traditional MINLP optimization method. The concepts ofspecies conserving and composite encoding are introduced to crowding genetic algorithm (CGA) formaintain the diversity of population more effectively and coping with the continuous and/or discretevariables in MINLP problem. The solution of three-levels pump configuration got from DICOPT++software (OA algorithm) is also given. By comparing with the solutions obtained from DICOPT++, ECPmethod, and MIN-MIN method, the ECGA algorithm proved to be very effective in finding the globaloptimal solution of multi-levels pump configuration via using the problem-specific information.展开更多
Modeling the elastic behavior of solids in energy conversion and storage devices such as fuel cells and lithium-ion batteries is usually difficult because of the nonlinear characteristics and the coupled chemo-mechani...Modeling the elastic behavior of solids in energy conversion and storage devices such as fuel cells and lithium-ion batteries is usually difficult because of the nonlinear characteristics and the coupled chemo-mechanical behavior of these solids.In this work,a perturbation finite element(FE)formulation is developed to analyze chemo-elastic boundary value problems(BVPs)under chemical equilibrium.The perturbation method is applied to the FE equations because of the nonlinearity in the chemical potential expression as a function of solute concentration.The compositional expansion coefficient is used as the perturbation parameter.After the perturbation expansion,a system of partial differential equations for the displacement and dimensionless solute concentration functions is obtained and solved in consecutive steps.The presence of a numerical solution enables modeling 3D chemo-elastic solids,such as battery electrodes or ionic gels,of any geometric shape with defects of different shapes.The proposed method is tested in several numerical examples such as plates with circular or elliptical holes,and cracks.The numerical examples showed how the shape of the defect can change the distribution of solute concentration around the defect.Cracks in chemo-elastic solids create sharp peaks in solute concentration around crack tips,and the intensity of these peaks increases as the far field solute concentration decreases.展开更多
We investigate the asymptotic behavior of solutions to the initial boundary value problem for the micropolar fluid model in a half line R+:=(0,∞).Inspired by the relationship between a micropolar fluid model and Navi...We investigate the asymptotic behavior of solutions to the initial boundary value problem for the micropolar fluid model in a half line R+:=(0,∞).Inspired by the relationship between a micropolar fluid model and Navier-Stokes equations,we prove that the composite wave consisting of the transonic boundary layer solution,the 1-rarefaction wave,the viscous 2-contact wave and the 3-rarefaction wave for the inflow problem on the micropolar fluid model is time-asymptotic ally stable under some smallness conditions.Meanwhile,we obtain the global existence of solutions based on the basic energy method.展开更多
Based on the biological key-lock-principle common in various biological systems such as the human brain, this paper relates to a method and device for creating problem-solving complexes from individual elements that c...Based on the biological key-lock-principle common in various biological systems such as the human brain, this paper relates to a method and device for creating problem-solving complexes from individual elements that can be coupled with one another and that have different properties to solve problems. The problem solution can be carried out either serially with a large computer, or with several independent, hierarchically joined computers. In this system, an independent control unit that assumes a multitude of tasks and also acts as an interface with access to all participating computers, is assigned to each problem or object class according to the amount of potential problem-oriented solutions. Such a unit prepares the partial solutions found in its computer for the totality of the solutions computed in the associated computers, finally leading to a total problem solution.展开更多
基金Supported by the National Natural Science Foundation of China (10791203, 11271340)the Natural Science Foundation of Henan Province (112300410109)
文摘Composite penalty method of a low order anisotropic nonconforming quadrilateral finite element for the Stokes problem is presented. This method with a large penalty parameter can achieve the same accuracy as the stand method with a small penalty parameter and the convergence rate of this method is two times as that of the standard method under the condition of the same order penalty parameter. The superconvergence for velocity is established as well. The results of this paper are also valid to the most of the known nonconforming finite element methods.
文摘This paper presents a parallel composite local search algorithm based on multiple search neighborhoods to solve a special kind of timetable problem. The new algorithm can also effectively solve those problems that can be solved by general local search algorithms. Experimental results show that the new algorithm can generate better solutions than general local search algorithms.
基金supported by the National Natural Science Foundation of China(60774064)the Aerospace Science Foundation (20085153015)
文摘This article introduces a fleet composition algorithm for a fleet of intermediate carriers, which should deliver a swarm of miniature unmanned aerial vehicles （mini-UAVs） to a mission area. The algorithm is based on the sequential solution of several knapsack problems with various constraints. The algorithm allows both to form an initial set of required types of intermediate carriers, and to generate a fleet of intermediate carriers. The formation of a fleet of intermediate carriers to solve a suppression of enemy air defense （SEAD） problem is presented to illustrate the proposed algorithm.
基金This work is supported by the National Natural Science Foundation of China under the Grant 19772037 and 19902014
文摘Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of linear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an effective tool to investigate the nonlinear problems.
基金This work was partially supported by the NSFC Projects No.12025104,11871298,81930119.
文摘In this paper,we generalize the direct method of lines for linear elasticity problems of composite materials in star-shaped domains and consider its application to inverse elasticity problems.We assume that the boundary of the star-shaped domain can be described by an explicit C 1 parametric curve in the polar coordinate.We introduce the curvilinear coordinate,in which the irregular star-shaped domain is converted to a regular semi-infinite strip.The equations of linear elasticity are discretized with respect to the angular variable and we solve the resulting semidiscrete approximation analytically using a direct method.The eigenvalues of the semi-discrete approximation converge quickly to the true eigenvalues of the elliptic operator,which helps capture the singularities naturally.Moreover,an optimal error estimate of our method is given.For the inverse elasticity problems,we determine the Lam´e coefficients from measurement data by minimizing a regularized energy functional.We apply the direct method of lines as the forward solver in order to cope with the irregularity of the domain and possible singularities in the forward solutions.Several numerical examples are presented to show the effectiveness and accuracy of our method for both forward and inverse elasticity problems of composite materials.
基金This project is supported by Provincial Science Foundation of Hebei (No.01213553).
文摘An extended crowding genetic algorithm (ECGA) is introduced for solvingoptimal pump configuration problem, which was presented by T. Westerlund in 1994. This problem hasbeen found to be non-convex, and the objective function contained several local optima and globaloptimality could not be ensured by all the traditional MINLP optimization method. The concepts ofspecies conserving and composite encoding are introduced to crowding genetic algorithm (CGA) formaintain the diversity of population more effectively and coping with the continuous and/or discretevariables in MINLP problem. The solution of three-levels pump configuration got from DICOPT++software (OA algorithm) is also given. By comparing with the solutions obtained from DICOPT++, ECPmethod, and MIN-MIN method, the ECGA algorithm proved to be very effective in finding the globaloptimal solution of multi-levels pump configuration via using the problem-specific information.
文摘Modeling the elastic behavior of solids in energy conversion and storage devices such as fuel cells and lithium-ion batteries is usually difficult because of the nonlinear characteristics and the coupled chemo-mechanical behavior of these solids.In this work,a perturbation finite element(FE)formulation is developed to analyze chemo-elastic boundary value problems(BVPs)under chemical equilibrium.The perturbation method is applied to the FE equations because of the nonlinearity in the chemical potential expression as a function of solute concentration.The compositional expansion coefficient is used as the perturbation parameter.After the perturbation expansion,a system of partial differential equations for the displacement and dimensionless solute concentration functions is obtained and solved in consecutive steps.The presence of a numerical solution enables modeling 3D chemo-elastic solids,such as battery electrodes or ionic gels,of any geometric shape with defects of different shapes.The proposed method is tested in several numerical examples such as plates with circular or elliptical holes,and cracks.The numerical examples showed how the shape of the defect can change the distribution of solute concentration around the defect.Cracks in chemo-elastic solids create sharp peaks in solute concentration around crack tips,and the intensity of these peaks increases as the far field solute concentration decreases.
基金The research was supported by the National Natural Science Foundation of China(11601164,11971183)the Fundamental Research Funds for the Central Universities(ZQN-701)the Natural Science Foundation of Fujian Province of China(2020J01071).
文摘We investigate the asymptotic behavior of solutions to the initial boundary value problem for the micropolar fluid model in a half line R+:=(0,∞).Inspired by the relationship between a micropolar fluid model and Navier-Stokes equations,we prove that the composite wave consisting of the transonic boundary layer solution,the 1-rarefaction wave,the viscous 2-contact wave and the 3-rarefaction wave for the inflow problem on the micropolar fluid model is time-asymptotic ally stable under some smallness conditions.Meanwhile,we obtain the global existence of solutions based on the basic energy method.
文摘Based on the biological key-lock-principle common in various biological systems such as the human brain, this paper relates to a method and device for creating problem-solving complexes from individual elements that can be coupled with one another and that have different properties to solve problems. The problem solution can be carried out either serially with a large computer, or with several independent, hierarchically joined computers. In this system, an independent control unit that assumes a multitude of tasks and also acts as an interface with access to all participating computers, is assigned to each problem or object class according to the amount of potential problem-oriented solutions. Such a unit prepares the partial solutions found in its computer for the totality of the solutions computed in the associated computers, finally leading to a total problem solution.
