Prestress enables the Glulam beam could make full use of the compression strength,and then increase the span,but it still could not reduce all drawbacks,such as cross-section weakening and small force arm.To avoid slo...Prestress enables the Glulam beam could make full use of the compression strength,and then increase the span,but it still could not reduce all drawbacks,such as cross-section weakening and small force arm.To avoid slotting and ensure suitable tension and compression couple,one kind of novel anchor has been proposed,which could meet the bearing capacity requirement.And then the bending test of prestressed Glulam beams with a geometric scale ratio of 1:2 was simulated,to investigate the effect of the force arm on bending capacities,failure modes,and deformation performance.Results show that increasing the force arm could improve the ultimate bending per-formance of the beam significantly,and the anchor arm length has a certain effect on the performance,but it is not obvious.Finally,based on Finite element method analysis,the practice design suggestions have been offered.展开更多
The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics ...The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics of the components.For the conventional frequency-domain electromagnetic analysis using FEM(Finite Element Method),the system matrix is complex-numbered as well as indefinite.The iterative solvers can be faster than the direct solver when the solver convergence is guaranteed and done in a few steps.However,such complex-numbered and indefinite systems are hard to exploit the merit of the iterative solver.It is also hard to benefit from matrix factorization techniques due to varying system matrix parts according to frequency.Overall,it is hard to adopt conventional iterative solvers even though the system matrix is sparse.A new parallel iterative FEM solver for frequency domain analysis is implemented for inhomogeneous waveguide structures in this paper.In this implementation,the previous solution of the iterative solver of Matlab(Matrix Laboratory)employ-ing the preconditioner is used for the initial guess for the next step’s solution process.The overlapped parallel stage using Matlab’s Parallel Computing Toolbox is also proposed to alleviate the cold starting,which ruins the convergence of early steps in each parallel stage.Numerical experiments based on waveguide structures have demonstrated the accuracy and efficiency of the proposed scheme.展开更多
In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be use...In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.展开更多
This paper theoretically introduced the feasibility of changing the vibration characteristics offlexible plates by using bio-inspired,extremely light,and powerful Pneumatic Artificial Muscle(PAM)actuators.Many structura...This paper theoretically introduced the feasibility of changing the vibration characteristics offlexible plates by using bio-inspired,extremely light,and powerful Pneumatic Artificial Muscle(PAM)actuators.Many structural plates or shells are typicallyflexible and show highvibration sensitivity.For this reason,this paper provides a way toachieve active vibrationcontrolfor suppressing the oscillations ofthese structuresto meet strict stability,safety,and comfort requirements.The dynamic behaviors of the designed plates are modeled by using thefinite element(FE)method.As is known,the output force vs.contraction curve of PAM is nonlinear generally.In this presentfinite element model,the maximum forces provided by PAM in different air pressure are adopted as controlling forces for applying for the plate.The non-linearity between the output force and displacement of PAM is avoided in this study.The dynamic behaviors of plates with several independent groups of controlling forces are observed and studied.The results show that the natural frequencies of the plate can be varying and the max amplitude decreases significantly if the controlling forces are applied.The present work also demonstrates the potential of the PAM actuators as valid means for damping out the vibration offlexible systems.展开更多
In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,...In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,the two tangent components of the displacement are discretized by using conformingfinite elements(linear element),and the normal component of the displacement is discretized by us-ing conforming Hsieh-Clough-Tocher element(HCT element).Then,the existence,uniqueness,stability,convergence and a priori error estimate of the corresponding analyses are proven and analyzed.Finally,we present numerical experiments with a portion of the conical shell and a portion of the cylindrical shell to verify theoretical convergence results and demonstrate the effectiveness of the numerical scheme.展开更多
A new algorithm,called symmetric inertial alternating direction method of multipliers(SIADMM),is designed for separable convex optimization problems with linear constraints in this paper.The convergence rate of the SI...A new algorithm,called symmetric inertial alternating direction method of multipliers(SIADMM),is designed for separable convex optimization problems with linear constraints in this paper.The convergence rate of the SIADMM is proved to be O(1/√k).Two kinds of elliptic equation constrained optimization problems,the un-constrained cases as well as the box-constrained cases of the distributed control and the Robin boundary control,are analyzed theoretically and solved numerically.First,the existence and uniqueness of the solutions to these problems are proved.Second,these continuous optimization problems are transformed into discrete optimization problems by thefinite element method,and then the discrete optimization problems are solved by the proposed SIADMM.Numerical experiments with different problems are investigated to demonstrate the efficiency of the SIADMM.And the numerical per-formance of the SIADMM is better than the performance of the ADMM.Moreover,the numerical results show that the convergence rate of the SIADMM tends to be faster than O(1/√k)in calculation process.展开更多
The superconvergence of a two-dimensional time-independent nonlinear Schrodinger equation are analyzed with the rectangular Lagrange typefinite element of order k.Firstly,the error estimate and superclose property are ...The superconvergence of a two-dimensional time-independent nonlinear Schrodinger equation are analyzed with the rectangular Lagrange typefinite element of order k.Firstly,the error estimate and superclose property are given in H^(1)-norm with order O(h^(k+1))between thefinite element solution u_(h) and the interpolation func-tion uI by use of the elliptic projection operator.Then,the global superconvergence is obtained by the interpolation post-processing technique.In addition,some numerical examples with the order k=1 and k=2 are provided to demonstrate the theoretical analysis.展开更多
In this paper,the Chebyshev-Galerkin spectral approximations are em-ployed to investigate Poisson equations and the fourth order equations in one dimen-sion.Meanwhile,p-version finite element methods with Chebyshev po...In this paper,the Chebyshev-Galerkin spectral approximations are em-ployed to investigate Poisson equations and the fourth order equations in one dimen-sion.Meanwhile,p-version finite element methods with Chebyshev polynomials are utilized to solve Poisson equations.The efficient and reliable a posteriori error esti-mators are given for different models.Furthermore,the a priori error estimators are derived independently.Some numerical experiments are performed to verify the the-oretical analysis for the a posteriori error indicators and a priori error estimations.展开更多
基金supported by the Resources Industry Science and Technology Innovation Joint Funding Project of Nanping(N2021Z003)the Special Project of Service Industry Research of Wuyi University under Grant(2021XJFWCY03)+2 种基金the Research Launch Fund of Wuyi University’s Introduct Talent(YJ202309)the Fujian Training Program of Innovation and Entrepreneurship for Undergraduates(S202210397076)Research on the Stress Performance of Reinforced Bamboo Highway Guardrail with Embedded Channel Steel(LS202304).
文摘Prestress enables the Glulam beam could make full use of the compression strength,and then increase the span,but it still could not reduce all drawbacks,such as cross-section weakening and small force arm.To avoid slotting and ensure suitable tension and compression couple,one kind of novel anchor has been proposed,which could meet the bearing capacity requirement.And then the bending test of prestressed Glulam beams with a geometric scale ratio of 1:2 was simulated,to investigate the effect of the force arm on bending capacities,failure modes,and deformation performance.Results show that increasing the force arm could improve the ultimate bending per-formance of the beam significantly,and the anchor arm length has a certain effect on the performance,but it is not obvious.Finally,based on Finite element method analysis,the practice design suggestions have been offered.
基金supported by Institute of Information&communications Technology Planning&Evaluation(ITP)grant funded by the Korea govermment(MSIT)(No.2019-0-00098,Advanced and Integrated Software Development for Electromagnetic Analysis)supported by Research Assistance Program(2021)in the Incheon National University.
文摘The finite element method is a key player in computational electromag-netics for designing RF(Radio Frequency)components such as waveguides.The frequency-domain analysis is fundamental to identify the characteristics of the components.For the conventional frequency-domain electromagnetic analysis using FEM(Finite Element Method),the system matrix is complex-numbered as well as indefinite.The iterative solvers can be faster than the direct solver when the solver convergence is guaranteed and done in a few steps.However,such complex-numbered and indefinite systems are hard to exploit the merit of the iterative solver.It is also hard to benefit from matrix factorization techniques due to varying system matrix parts according to frequency.Overall,it is hard to adopt conventional iterative solvers even though the system matrix is sparse.A new parallel iterative FEM solver for frequency domain analysis is implemented for inhomogeneous waveguide structures in this paper.In this implementation,the previous solution of the iterative solver of Matlab(Matrix Laboratory)employ-ing the preconditioner is used for the initial guess for the next step’s solution process.The overlapped parallel stage using Matlab’s Parallel Computing Toolbox is also proposed to alleviate the cold starting,which ruins the convergence of early steps in each parallel stage.Numerical experiments based on waveguide structures have demonstrated the accuracy and efficiency of the proposed scheme.
基金supported by the National Natural Science Foundation of China(No.11971152)the Fundamental Research Funds for the Universities of Henan Province(No.NSFRF180421)。
文摘In this paper,a numerical method for the electroneutral micro-fluids based on thefinite element method will be given.In order to deal with the non-linearity of the equation,the modified characteristics method will be used to deal with the tempo-ral derivates term and the convective term.In this way,the non-linear equation can be linearlized.Then,we will give the unconditional stability and optimal error estima-tion.At last,some numerical results are given to show the effectiveness of our method.From the stability analysis we can see that the method is unconditionally stable.The numerical results show that our method is robust.
基金supported by the Henan Provincial Science and Technology Research Project(222102220068).
文摘This paper theoretically introduced the feasibility of changing the vibration characteristics offlexible plates by using bio-inspired,extremely light,and powerful Pneumatic Artificial Muscle(PAM)actuators.Many structural plates or shells are typicallyflexible and show highvibration sensitivity.For this reason,this paper provides a way toachieve active vibrationcontrolfor suppressing the oscillations ofthese structuresto meet strict stability,safety,and comfort requirements.The dynamic behaviors of the designed plates are modeled by using thefinite element(FE)method.As is known,the output force vs.contraction curve of PAM is nonlinear generally.In this presentfinite element model,the maximum forces provided by PAM in different air pressure are adopted as controlling forces for applying for the plate.The non-linearity between the output force and displacement of PAM is avoided in this study.The dynamic behaviors of plates with several independent groups of controlling forces are observed and studied.The results show that the natural frequencies of the plate can be varying and the max amplitude decreases significantly if the controlling forces are applied.The present work also demonstrates the potential of the PAM actuators as valid means for damping out the vibration offlexible systems.
基金supported by the National Natural Science Foundation of China(NSFC Nos.11971379,12071149)the Natural Science Foundation of Shanghai(Grant No.19ZR1414100)。
文摘In this paper,we propose a conformingfinite element method coupling penalty method for the linearly elasticflexural shell to overcome computational dif-ficulties.We start with discretizing the displacement variable,i.e.,the two tangent components of the displacement are discretized by using conformingfinite elements(linear element),and the normal component of the displacement is discretized by us-ing conforming Hsieh-Clough-Tocher element(HCT element).Then,the existence,uniqueness,stability,convergence and a priori error estimate of the corresponding analyses are proven and analyzed.Finally,we present numerical experiments with a portion of the conical shell and a portion of the cylindrical shell to verify theoretical convergence results and demonstrate the effectiveness of the numerical scheme.
基金This work was supported by National Natural Science Foundation of China(Grant Nos.12171052,11871115 and 11671052)BUPT Excellent Ph.D.Students Foundation(Grant No.CX2021320).The authors sincerely thank Prof.Haiming Song and Doctor Xin Gao for their valuable discussions.The authors also thank all of the editors and reviewers for their very important suggestions.
文摘A new algorithm,called symmetric inertial alternating direction method of multipliers(SIADMM),is designed for separable convex optimization problems with linear constraints in this paper.The convergence rate of the SIADMM is proved to be O(1/√k).Two kinds of elliptic equation constrained optimization problems,the un-constrained cases as well as the box-constrained cases of the distributed control and the Robin boundary control,are analyzed theoretically and solved numerically.First,the existence and uniqueness of the solutions to these problems are proved.Second,these continuous optimization problems are transformed into discrete optimization problems by thefinite element method,and then the discrete optimization problems are solved by the proposed SIADMM.Numerical experiments with different problems are investigated to demonstrate the efficiency of the SIADMM.And the numerical per-formance of the SIADMM is better than the performance of the ADMM.Moreover,the numerical results show that the convergence rate of the SIADMM tends to be faster than O(1/√k)in calculation process.
基金The authors would like to express the sincere thanks to anonymous referees for their valuable comments.This research is supported by National Natural Science Foundation of China(No.11671340)Hunan Provincial Natural Science Foundation of China(Nos.2021JJ30209,2021JJ50108 and 2021JJ30178).
文摘The superconvergence of a two-dimensional time-independent nonlinear Schrodinger equation are analyzed with the rectangular Lagrange typefinite element of order k.Firstly,the error estimate and superclose property are given in H^(1)-norm with order O(h^(k+1))between thefinite element solution u_(h) and the interpolation func-tion uI by use of the elliptic projection operator.Then,the global superconvergence is obtained by the interpolation post-processing technique.In addition,some numerical examples with the order k=1 and k=2 are provided to demonstrate the theoretical analysis.
基金This work was supported by National Natural Science Foun-dation of China(Grant No.11201212 and 11301252),CSC(No.201408380045)Promotive Research Fund for Excellent Young and Middle-Aged Scientists of Shandong Province(No.BS2012DX004)and AMEP of Linyi University.
文摘In this paper,the Chebyshev-Galerkin spectral approximations are em-ployed to investigate Poisson equations and the fourth order equations in one dimen-sion.Meanwhile,p-version finite element methods with Chebyshev polynomials are utilized to solve Poisson equations.The efficient and reliable a posteriori error esti-mators are given for different models.Furthermore,the a priori error estimators are derived independently.Some numerical experiments are performed to verify the the-oretical analysis for the a posteriori error indicators and a priori error estimations.
