This paper puts forward a new integrated design met ho d based on fuzzy matter-element optimization.On the based of analyzing the mod el of multi-objective fuzzy matter-element , the paper defines the m atter-element ...This paper puts forward a new integrated design met ho d based on fuzzy matter-element optimization.On the based of analyzing the mod el of multi-objective fuzzy matter-element , the paper defines the m atter-element weightily and changes solving multi-objective fuzzy optimization into solving dependent function K(x) of the single-objective optimization according to the optimization criterion. The paper particularly describes the realization approach of GA process of multi -objective fuzzy matter-element optimization: encode, produce initial populati on, confirm fitness function, select operator, etc. In the process, the adaptive macro genetic algorithms (AMGA) is applied to enhancing the evolution speed. Th e paper improves the two genetic operators: crossover and mutation operator. The modified adaptive macro genetic algorithms (MAMGA) is put forward simultane ously. It is adopted to solve the optimization problem. Three optimization methods, namely fuzzy matter-element optimization method, li nearity weighted method and fuzzy optimization method, are compared by using the table and figure, it shows that not only MAMGA is a little better than the AMGA , but also it reaches the extent to which the effective iteration generation is 62.2% of simple genetic algorithms (SGA). By the calculation of optimum exam ple, the improved method of genetic in the paper is much better than the method in reference of paper.展开更多
Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than...Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than the usual 12 parameter rectangular plate elements.展开更多
This paper studies the finite element method for some nonlinear hyperbolic partial differential equations with memory and dampling terms.A Crank\|Nicolson approximation for this kind of equations is presented.By using...This paper studies the finite element method for some nonlinear hyperbolic partial differential equations with memory and dampling terms.A Crank\|Nicolson approximation for this kind of equations is presented.By using the elliptic Ritz\|Volterra projection,the analysis of the error estimates for the finite element numerical solutions and the optimal H \+1\|norm error estimate are demonstrated.展开更多
The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand ac...The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand actuatorsunderapplied transverse loads. In this paper, the increm ental finite elem entequationsconsidering thegeom etricnonlinearity ofpiezoelectricsm artstructuresarede- veloped based on TotalLagrange approach by using the virtualvelocity increm entalvariationalprinci- ples. A four-node Mindlin plate elem ent w ith reduced and selective integration is adopted. The re- sulting increm entequationsare solved by using New m ark'sdirectintegration approach. Transientre- sponse ofplatesw ith piezoelectricsensorsand actuators subjected to transverse dynam ic loading isin- vestigated. The active dam ping isintroduced on the platesby coupling a negativevelocity feedback al- gorithm in a closed controlloop. The num ericalresults show thatpiezoelectric actuators can produce significant dam ping and suppress transient vibration effectively. Finally, the effects of the num ber and locations ofthe piezoelectric actuatorson the controlsystem are also investigated.展开更多
In this paper,a new numerical method,the coupling method of spherical harmonic function spectral and finite elements,for a unsteady transport equation is discussed,and the error analysis of this scheme is proved.
Two\|phase ,miscible,incompressible flow in porous media is governed by a system of nonlinear partial differential equations.Many numerical methods have been given by different authors to this system,but these methods...Two\|phase ,miscible,incompressible flow in porous media is governed by a system of nonlinear partial differential equations.Many numerical methods have been given by different authors to this system,but these methods need very high regularity conditions.Actually,in most practical applications these regularity conditions couldn't be satisfied.In this paper,the problem of discontinuous coefficients with lower regularity conditions is considered and the error estimates are demonstrated.展开更多
Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents th...Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.展开更多
The mold filling of RTM was simulated based on the control volume finite element method (CV/FEM). The formulat ion using isoparametric transformation was discussed in detail and a computation al code based on isopara...The mold filling of RTM was simulated based on the control volume finite element method (CV/FEM). The formulat ion using isoparametric transformation was discussed in detail and a computation al code based on isoparametric technique was developed. The simulation results w ere compared with experimental data. Different isoparametric elements, quadrilat eral and triangular, were compared in the simulation.It demonstrates that the us e of bilinear quadrilateral isoparametric elements in simulating the process can produce a higher precision and cost a less time than the use of triangular ones .展开更多
采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定...采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定了倒装焊 Sn Pb焊点热循环失效 Coffin- Manson经验方程的材料参数 .研究表明 ,有底充胶倒装焊 Sn Pb焊点的塑性应变范围比无底充胶时明显减小 ,热循环寿命可提高约 2 0倍 。展开更多
文摘This paper puts forward a new integrated design met ho d based on fuzzy matter-element optimization.On the based of analyzing the mod el of multi-objective fuzzy matter-element , the paper defines the m atter-element weightily and changes solving multi-objective fuzzy optimization into solving dependent function K(x) of the single-objective optimization according to the optimization criterion. The paper particularly describes the realization approach of GA process of multi -objective fuzzy matter-element optimization: encode, produce initial populati on, confirm fitness function, select operator, etc. In the process, the adaptive macro genetic algorithms (AMGA) is applied to enhancing the evolution speed. Th e paper improves the two genetic operators: crossover and mutation operator. The modified adaptive macro genetic algorithms (MAMGA) is put forward simultane ously. It is adopted to solve the optimization problem. Three optimization methods, namely fuzzy matter-element optimization method, li nearity weighted method and fuzzy optimization method, are compared by using the table and figure, it shows that not only MAMGA is a little better than the AMGA , but also it reaches the extent to which the effective iteration generation is 62.2% of simple genetic algorithms (SGA). By the calculation of optimum exam ple, the improved method of genetic in the paper is much better than the method in reference of paper.
文摘Using the method of undetermined function, a set of 12 parameter rectangular plate element with double set parameter and geometry symmetry is constructed. Their consistency error are O(h\+2) , one order higher than the usual 12 parameter rectangular plate elements.
文摘This paper studies the finite element method for some nonlinear hyperbolic partial differential equations with memory and dampling terms.A Crank\|Nicolson approximation for this kind of equations is presented.By using the elliptic Ritz\|Volterra projection,the analysis of the error estimates for the finite element numerical solutions and the optimal H \+1\|norm error estimate are demonstrated.
文摘The transientbehaviorofisotropic and hom ogeneousplateshasbeen a subjectofinterest. Thepresentinvestigation isconcerned w ith the largedeflection transientanalysisand controlofplates w ith piezoelectricsensorsand actuatorsunderapplied transverse loads. In this paper, the increm ental finite elem entequationsconsidering thegeom etricnonlinearity ofpiezoelectricsm artstructuresarede- veloped based on TotalLagrange approach by using the virtualvelocity increm entalvariationalprinci- ples. A four-node Mindlin plate elem ent w ith reduced and selective integration is adopted. The re- sulting increm entequationsare solved by using New m ark'sdirectintegration approach. Transientre- sponse ofplatesw ith piezoelectricsensorsand actuators subjected to transverse dynam ic loading isin- vestigated. The active dam ping isintroduced on the platesby coupling a negativevelocity feedback al- gorithm in a closed controlloop. The num ericalresults show thatpiezoelectric actuators can produce significant dam ping and suppress transient vibration effectively. Finally, the effects of the num ber and locations ofthe piezoelectric actuatorson the controlsystem are also investigated.
文摘In this paper,a new numerical method,the coupling method of spherical harmonic function spectral and finite elements,for a unsteady transport equation is discussed,and the error analysis of this scheme is proved.
文摘Two\|phase ,miscible,incompressible flow in porous media is governed by a system of nonlinear partial differential equations.Many numerical methods have been given by different authors to this system,but these methods need very high regularity conditions.Actually,in most practical applications these regularity conditions couldn't be satisfied.In this paper,the problem of discontinuous coefficients with lower regularity conditions is considered and the error estimates are demonstrated.
基金The work was supported by the National Natural Science Foundation(Nos.51625101,51431009,5180118&and 51701202)the State Key Development Program for Basic Research of China(No.2015CB921401)+3 种基金the Fundamental Research Funds for the Central University Universities of China(No.FRF-TP-16-001C2)the China Postdoctoral Science Foundation(No.2018M632792)Startup Research Fund of Zhengzhou University(No.32210815)Bejing Natural Science Foundation(No.Z180014).
文摘Pt-based magnetic nano catalysts are one of the most suitable cand idates for electrocatalytic materials due to their high electrochemistry activity and retrievability.Unfortunately,the inferior durability prevents them from being scaled-up,limiting their commercial applications.Herein,an antiferromagnetic element Mn was introduced into PtCo nanostructured alloy to synthesize uniform Mn-PtCo truncated octahedral nanoparticles(TONPs)by one-pot method.Our results show that Mn can tune the blocking temperature of Mn-PtCo TONPs due to its an tiferromag netism.At low temperatures,Mn-PtCo TONPs are ferromag netic,and the coercivity in creases gradually with in creasi ng Mn contents.At room temperature,the Mn-PtCo TONPs display superparamag netic behavior,which is greatly helpful for in dustrial recycling.Mn doping can not only modify the electronic structure of PtCo TONPs but also enhanee electrocatalytic performance for methanol oxidation reaction.The maximum specific activity of Mn-PtCo-3 reaches 8.1 A`m^-2,3.6 times of commercial Pt/C(2.2 A·m^-2)and 1.4 times of PtCo TONPs(5.6 A`m^-2),respectively.The mass activity decreases by only 30%after 2,000 cycles,while it is 45%and 99%(nearly inactive)for PtCo TONPs and commercial Pt/C catalysts,respectively.
基金Funded by the National Natural Science Foundation of China ( 19872051 ) and the National "863" H tech Foundation(2001AA335020)
文摘The mold filling of RTM was simulated based on the control volume finite element method (CV/FEM). The formulat ion using isoparametric transformation was discussed in detail and a computation al code based on isoparametric technique was developed. The simulation results w ere compared with experimental data. Different isoparametric elements, quadrilat eral and triangular, were compared in the simulation.It demonstrates that the us e of bilinear quadrilateral isoparametric elements in simulating the process can produce a higher precision and cost a less time than the use of triangular ones .
文摘采用实验方法 ,确定了倒装焊 Sn Pb焊点的热循环寿命 .采用粘塑性和粘弹性材料模式描述了 Sn Pb焊料和底充胶的力学行为 ,用有限元方法模拟了 Sn Pb焊点在热循环条件下的应力应变过程 .基于计算的塑性应变范围和实验的热循环寿命 ,确定了倒装焊 Sn Pb焊点热循环失效 Coffin- Manson经验方程的材料参数 .研究表明 ,有底充胶倒装焊 Sn Pb焊点的塑性应变范围比无底充胶时明显减小 ,热循环寿命可提高约 2 0倍 。
