This paper firstly defined the concept of folk culture block,and then analyzed the significance and planning principle of landscape design in folk culture block,and at last expounded landscape planning and design of f...This paper firstly defined the concept of folk culture block,and then analyzed the significance and planning principle of landscape design in folk culture block,and at last expounded landscape planning and design of folk culture block based on theory of three elements of landscape.展开更多
With the introduction of Poisson's ratio in the expression of Young's modulus,nearly all the theoretical values of the various elastic moduli for the alkaline earth metals and rare earth elements can be greatl...With the introduction of Poisson's ratio in the expression of Young's modulus,nearly all the theoretical values of the various elastic moduli for the alkaline earth metals and rare earth elements can be greatly refined, with the single exception of the theoreticalvalue of Young's modulus for Pr which is slightly increased This points to the validityof the new theory, that the bulk modulus is independent of the Poisson's ratio, and further that the valency electron structures of solids as determined by Yu's theory are correct.展开更多
Because the deployable structures are complex multi-loop structures and methods of derivation which lead to simpler kinematic and dynamic equations of motion are the subject of research effort, the kinematics and dyna...Because the deployable structures are complex multi-loop structures and methods of derivation which lead to simpler kinematic and dynamic equations of motion are the subject of research effort, the kinematics and dynamics of deployable structures with scissor-like-elements are presented based on screw theory and the principle of virtual work respectively. According to the geometric characteristic of the deployable structure examined, the basic structural unit is the common scissor-like-element(SLE). First, a spatial deployable structure, comprised of three SLEs, is defined, and the constraint topology graph is obtained. The equations of motion are then derived based on screw theory and the geometric nature of scissor elements. Second, to develop the dynamics of the whole deployable structure, the local coordinates of the SLEs and the Jacobian matrices of the center of mass of the deployable structure are derived. Then, the equivalent forces are assembled and added in the equations of motion based on the principle of virtual work. Finally, dynamic behavior and unfolded process of the deployable structure are simulated. Its figures of velocity, acceleration and input torque are obtained based on the simulate results. Screw theory not only provides an efficient solution formulation and theory guidance for complex multi-closed loop deployable structures, but also extends the method to solve dynamics of deployable structures. As an efficient mathematical tool, the simper equations of motion are derived based on screw theory.展开更多
The advent of the big data era has presented unprecedented challenges to remedies for personal information infringement in areas such as damage assessment,proof of causation,determination of illegality,fault assessmen...The advent of the big data era has presented unprecedented challenges to remedies for personal information infringement in areas such as damage assessment,proof of causation,determination of illegality,fault assessment,and liability.Traditional tort law is unable to provide a robust response for these challenges,which severely hinders human rights protection in the digital society.The dynamic system theory represents a third path between fixed constitutive elements and general clauses.It both overcomes the rigidity of the“allor-nothing”legal effect evaluation mechanism of the“element-effect”model and avoids the uncertainty of the general clause model.It can effectively enhance the flexibility of the legal system in responding to social changes.In light of this,it is necessary to construct a dynamic foundational evaluation framework for personal information infringement under the guidance of the dynamic system theory.By relying on the dynamic interplay effect of various foundational evaluation elements,this framework can achieve a flexible evaluation of the constitutive elements of liability and the legal effects of liability for personal information infringement.Through this approach,the crisis of personal information infringement in the era of big data can be mitigated,and the realization of personal information rights as digital human rights can be promoted.展开更多
Tourism texts (shortened as TT) have become a principal means of promoting tourism in China. Cultural elements are abundant in those texts. Therefore, the proper understanding and rendering of such messages is the k...Tourism texts (shortened as TT) have become a principal means of promoting tourism in China. Cultural elements are abundant in those texts. Therefore, the proper understanding and rendering of such messages is the key to the quality of TT translation. Based on Skopos theory the paper focuses on the translating strategies of TT cultural elements.展开更多
A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this...A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this aim, the micropolar theory is combined with the nonlocal elasticity. To consider the nonlocality, both integral (original) and differential formulations of Eringen’s nonlocal theory are considered. The beams are considered to be Timoshenko-type, and the governing equations are derived in the variational form through Hamilton’s principle. The relations are written in an appropriate matrix-vector representation that can be readily utilized in numerical approaches. A finite element (FE) approach is also proposed for the solution procedure. Parametric studies are conducted to show the simultaneous nonlocal and micropolar effects on the bending response of small-scale beams under different boundary conditions.展开更多
A new higher-order shear deformation theory based on global-local superposition technique is developed. The theory satisfies the free surface conditions and the geometric and stress continuity conditions at interfaces...A new higher-order shear deformation theory based on global-local superposition technique is developed. The theory satisfies the free surface conditions and the geometric and stress continuity conditions at interfaces. The global displacement components are of the Reddy theory and local components are of the internal first to third-order terms in each layer. A two-node beam element based on this theory is proposed. The solutions are compared with 3D-elasticity solutions. Numerical results show that present beam element has higher computational efficiency and higher accuracy.展开更多
In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. ...In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.展开更多
The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/stra...The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.展开更多
<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important app...<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail. </div>展开更多
This paper combines the perturbation theory with the boundary element methodfor contact problems of three-dimensional elasticity mechanism to analyse the effect oferrors on the shape of the contact area and pressure d...This paper combines the perturbation theory with the boundary element methodfor contact problems of three-dimensional elasticity mechanism to analyse the effect oferrors on the shape of the contact area and pressure distribution in gear drive through theperturbation of a cubic order geometry,there by greatly bringing down both computationwork volume and cost and providing a powerful tool for engineering study on the effectof errors on structural strength.展开更多
Quadrilateral finite elements for linear micropolar continuum theory are developed using linked interpolation.In order to satisfy convergence criteria,the newly presented finite elements are modified using the Petrov-...Quadrilateral finite elements for linear micropolar continuum theory are developed using linked interpolation.In order to satisfy convergence criteria,the newly presented finite elements are modified using the Petrov-Galerkin method in which different interpolation is used for the test and trial functions.The elements are tested through four numerical examples consisting of a set of patch tests,a cantilever beam in pure bending and a stress concentration problem and compared with the analytical solution and quadrilateral micropolar finite elements with standard Lagrangian interpolation.In the higher-order patch test,the performance of the first-order element is significantly improved.However,since the problems analysed are already describable with quadratic polynomials,the enhancement due to linked interpolation for higher-order elements could not be highlighted.All the presented elements also faithfully reproduce the micropolar effects in the stress concentration analysis,but the enhancement here is negligible with respect to standard Lagrangian elements,since the higher-order polynomials in this example are not needed.展开更多
Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some...Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some extent, be fairly described by the poroelasticity theory. Implementation of the poroelastieity theory in the framework of finite element method would aid the design and optimization of hydrogel-based soft devices. Choosing chemical potential and displacement as two field variables, we present the implementation of poroelastieity tailored for hydrogel swelling dynamics, detail the normalization of physical parameters and the treatment of boundary conditions. Several examples are presented to demonstrate the feasibility and correctness of the proposed strategy.展开更多
The basic idea of quasi-conforming method is that the strain-dis-placement equations are weakened as well as the equilibrium equations.In this paper,an 18-DOF triangular element for couple stress theory is proposed wi...The basic idea of quasi-conforming method is that the strain-dis-placement equations are weakened as well as the equilibrium equations.In this paper,an 18-DOF triangular element for couple stress theory is proposed within the framework of quasi-conforming technique.The formulation starts from truncated Taylor expansion of strains and appropriate interpolation functions are chosen to calculate strain integration.This element satisfies C0 continuity with second order accuracy and weak C1 continuity simultaneously.Numerical examples demonstrate that the proposed model can pass the C0??1 patch test and has high accuracy.The element does not exhibit extra zero energy modes and can capture the scale effects of microstructure.展开更多
Based on the micropolar theory(MPT),a two-dimensional(2 D)element is proposed to describe the free vibration response of structures.In the context of the MPT,a 2 D formulation is developed within the ABAQUS finite ele...Based on the micropolar theory(MPT),a two-dimensional(2 D)element is proposed to describe the free vibration response of structures.In the context of the MPT,a 2 D formulation is developed within the ABAQUS finite element software.The user-defined element(UEL)subroutine is used to implement a micropolar element.The micropolar effects on the vibration behavior of 2 D structures with arbitrary shapes are studied.The effect of micro-inertia becomes dominant,and by considering the micropolar effects,the frequencies decrease.Also,there is a considerable discrepancy between the predicted micropolar and classical frequencies at small scales,and this difference decreases when the side length-to-length scale ratio becomes large.展开更多
A new displacement based higher order element has been formulated that is ideally suitable for shear deformable composite and sandwich plates. Suitable functions for displacements and rotations for each node have been...A new displacement based higher order element has been formulated that is ideally suitable for shear deformable composite and sandwich plates. Suitable functions for displacements and rotations for each node have been selected so that the element shows rapid convergence, an excellent response against transverse shear loading and requires no shear correction factors. It is completely lock-free and behaves extremely well for thin to thick plates. To make the element rapidly convergent and to capture warping effects for composites, higher order displacement terms in the displacement kinematics have been considered for each node. The element has eleven degrees of freedom per node. Shear deformation has also been considered in the formulation by taking into account shear strains ( rxz and ryz) as nodal unknowns. The element is very simple to formulate and could be coded up in research software. A small Fortran code has been developed to implement the element and various examples of isotropic and composite plates have been analyzed to show the effectiveness of the element.展开更多
We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alka...We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.展开更多
In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
This paper introduces creativity,one of the significant features in maths.The creative mathematical beauty of symmetry and asymmetry are worth investigating in the practicing of Taichi.Symmetrical variances make the r...This paper introduces creativity,one of the significant features in maths.The creative mathematical beauty of symmetry and asymmetry are worth investigating in the practicing of Taichi.Symmetrical variances make the real world.Symmetry can be regarded as a kind of mirroring,like the line symmetry,the mirror image of the other parts,or rotational symmetry.Such characteristics can be vividly demonstrated in the traditional Chinese philosophical yin-yang theory(YY).The accompanying of male and female reveals the friendly cooperative relationship.YY reflects the counterparts of vacancy and firm,inhale and exhale,noun and verb,theory and practice,light and heavy,slow and fast,the pace,the sound effect in the classroom.Such an analysis is undergone about yin and yang in Yi School and Dao De Ching(DDC).Furthermore,there are detailed arguments of the symmetric nature of every verse of DDC,revealing the cultural value of the language.Their applications in the class admit the recognition under the new liberal arts project by China’s Ministry of Education.Yet,the integration of research and teaching is required to go further.展开更多
The application of digital technology in the field of construction is still in its infancy, and the existing concrete framework of digital technology application in the construction industry and the study of applied e...The application of digital technology in the field of construction is still in its infancy, and the existing concrete framework of digital technology application in the construction industry and the study of applied ecological elements are not enough. The ecological elements of digital technology application in the construction industry are important factors that promote the healthy op</span><span style="font-family:Verdana;">eration of the entire digital technology application ecosystem. </span><span style="font-family:Verdana;">Using grounded theory, we compiled the data of 33 researchers who participated in </span><span style="font-family:Verdana;">semi-structured interviews, and obtained 4 main categories and 9</span><span style="font-family:Verdana;"> sub-categories of ecological elements of digital technology application in the construction industry. Among them, the digital technology application mechanism is the core category of ecological application elements. We also used the Bass model to analyze the application trend of digital technology in the construction industry. </span><span style="font-family:Verdana;">In 2040, the number of construction companies applying digital</span><span style="font-family:Verdana;"> technology will reach 98.66% of the maximum market potential.展开更多
文摘This paper firstly defined the concept of folk culture block,and then analyzed the significance and planning principle of landscape design in folk culture block,and at last expounded landscape planning and design of folk culture block based on theory of three elements of landscape.
文摘With the introduction of Poisson's ratio in the expression of Young's modulus,nearly all the theoretical values of the various elastic moduli for the alkaline earth metals and rare earth elements can be greatly refined, with the single exception of the theoreticalvalue of Young's modulus for Pr which is slightly increased This points to the validityof the new theory, that the bulk modulus is independent of the Poisson's ratio, and further that the valency electron structures of solids as determined by Yu's theory are correct.
基金Supported by National Natural Science Foundation of China(Grant No.51175422)
文摘Because the deployable structures are complex multi-loop structures and methods of derivation which lead to simpler kinematic and dynamic equations of motion are the subject of research effort, the kinematics and dynamics of deployable structures with scissor-like-elements are presented based on screw theory and the principle of virtual work respectively. According to the geometric characteristic of the deployable structure examined, the basic structural unit is the common scissor-like-element(SLE). First, a spatial deployable structure, comprised of three SLEs, is defined, and the constraint topology graph is obtained. The equations of motion are then derived based on screw theory and the geometric nature of scissor elements. Second, to develop the dynamics of the whole deployable structure, the local coordinates of the SLEs and the Jacobian matrices of the center of mass of the deployable structure are derived. Then, the equivalent forces are assembled and added in the equations of motion based on the principle of virtual work. Finally, dynamic behavior and unfolded process of the deployable structure are simulated. Its figures of velocity, acceleration and input torque are obtained based on the simulate results. Screw theory not only provides an efficient solution formulation and theory guidance for complex multi-closed loop deployable structures, but also extends the method to solve dynamics of deployable structures. As an efficient mathematical tool, the simper equations of motion are derived based on screw theory.
基金the“Application of the Dynamic System Theory in the Determination of Infringement Liability for Immaterial Personality Rights in the Civil Code”(Project Approval Number 2022MFXH006)a project of the young scholar research program of the Civil Law Society of CLS in 2022。
文摘The advent of the big data era has presented unprecedented challenges to remedies for personal information infringement in areas such as damage assessment,proof of causation,determination of illegality,fault assessment,and liability.Traditional tort law is unable to provide a robust response for these challenges,which severely hinders human rights protection in the digital society.The dynamic system theory represents a third path between fixed constitutive elements and general clauses.It both overcomes the rigidity of the“allor-nothing”legal effect evaluation mechanism of the“element-effect”model and avoids the uncertainty of the general clause model.It can effectively enhance the flexibility of the legal system in responding to social changes.In light of this,it is necessary to construct a dynamic foundational evaluation framework for personal information infringement under the guidance of the dynamic system theory.By relying on the dynamic interplay effect of various foundational evaluation elements,this framework can achieve a flexible evaluation of the constitutive elements of liability and the legal effects of liability for personal information infringement.Through this approach,the crisis of personal information infringement in the era of big data can be mitigated,and the realization of personal information rights as digital human rights can be promoted.
文摘Tourism texts (shortened as TT) have become a principal means of promoting tourism in China. Cultural elements are abundant in those texts. Therefore, the proper understanding and rendering of such messages is the key to the quality of TT translation. Based on Skopos theory the paper focuses on the translating strategies of TT cultural elements.
文摘A novel size-dependent model is developed herein to study the bending behavior of beam-type micro/nano-structures considering combined effects of nonlocality and micro-rotational degrees of freedom. To accomplish this aim, the micropolar theory is combined with the nonlocal elasticity. To consider the nonlocality, both integral (original) and differential formulations of Eringen’s nonlocal theory are considered. The beams are considered to be Timoshenko-type, and the governing equations are derived in the variational form through Hamilton’s principle. The relations are written in an appropriate matrix-vector representation that can be readily utilized in numerical approaches. A finite element (FE) approach is also proposed for the solution procedure. Parametric studies are conducted to show the simultaneous nonlocal and micropolar effects on the bending response of small-scale beams under different boundary conditions.
基金The project supported by the National Natural Science Foundation of China(10172023)
文摘A new higher-order shear deformation theory based on global-local superposition technique is developed. The theory satisfies the free surface conditions and the geometric and stress continuity conditions at interfaces. The global displacement components are of the Reddy theory and local components are of the internal first to third-order terms in each layer. A two-node beam element based on this theory is proposed. The solutions are compared with 3D-elasticity solutions. Numerical results show that present beam element has higher computational efficiency and higher accuracy.
文摘In this study, a new method for conversion of solid finite element solution to beam finite element solution is developed based on the meta-modeling theory which constructs a model consistent with continuum mechanics. The proposed method is rigorous and efficient compared to a typical conversion method which merely computes surface integration of solid element nodal stresses to obtain cross-sectional forces. The meta-modeling theory ensures the rigorousness of proposed method by defining a proper distance between beam element and solid element solutions in a function space of continuum mechanics. Results of numerical verification test that is conducted with a simple cantilever beam are used to find the proper distance function for this conversion. Time history analysis of the main tunnel structure of a real ramp tunnel is considered as a numerical example for the proposed conversion method. It is shown that cross-sectional forces are readily computed for solid element solution of the main tunnel structure when it is converted to a beam element solution using the proposed method. Further, envelopes of resultant forces which are of primary importance for the purpose of design, are developed for a given ground motion at the end.
基金Project(50575143)supported by the National Natural Science Foundation of ChinaProject(20040248005)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.
文摘<div style="text-align:justify;"> Currently, coupled mode theory (CMT) is widely used for calculating the coupling coefficient of twin-core fibers (TCFs) that are used in a broad range of important applications. This approach is highly accurate for scenarios with weak coupling between the cores but shows significant errors in the strong coupling scenarios, necessitating the use of a more accurate method for coupling coefficient calculations. Therefore, in this work, we calculate the coupling coefficients of TCFs using the supermode theory with finite element method (FEM) that has higher accuracy than CMT, particularly for the strong coupling TCF. To investigate the origin of the differences between the results obtained by these two methods, the modal field distributions of the supermodes of TCF are simulated and analyzed in detail. </div>
文摘This paper combines the perturbation theory with the boundary element methodfor contact problems of three-dimensional elasticity mechanism to analyse the effect oferrors on the shape of the contact area and pressure distribution in gear drive through theperturbation of a cubic order geometry,there by greatly bringing down both computationwork volume and cost and providing a powerful tool for engineering study on the effectof errors on structural strength.
基金The research presented in this paper has been financially supported by the Croatian Science Foundation(Grants HRZZ-IP-11-2013-1631 and HRZZ-IP-2018-01-1732)Young Researchers'Career Development—Training of Doctoral Students,as well as a French Government Scholarship.
文摘Quadrilateral finite elements for linear micropolar continuum theory are developed using linked interpolation.In order to satisfy convergence criteria,the newly presented finite elements are modified using the Petrov-Galerkin method in which different interpolation is used for the test and trial functions.The elements are tested through four numerical examples consisting of a set of patch tests,a cantilever beam in pure bending and a stress concentration problem and compared with the analytical solution and quadrilateral micropolar finite elements with standard Lagrangian interpolation.In the higher-order patch test,the performance of the first-order element is significantly improved.However,since the problems analysed are already describable with quadratic polynomials,the enhancement due to linked interpolation for higher-order elements could not be highlighted.All the presented elements also faithfully reproduce the micropolar effects in the stress concentration analysis,but the enhancement here is negligible with respect to standard Lagrangian elements,since the higher-order polynomials in this example are not needed.
基金supported by the National Natural Science Foundation of China(11072185,11372239,and 11021202)
文摘Abstract Hydrogel can swell to many times of its dry volume, resulting in large deformation which is vital for its function. The swelling process is regulated by many physical and chemical mechanisms, and can, to some extent, be fairly described by the poroelasticity theory. Implementation of the poroelastieity theory in the framework of finite element method would aid the design and optimization of hydrogel-based soft devices. Choosing chemical potential and displacement as two field variables, we present the implementation of poroelastieity tailored for hydrogel swelling dynamics, detail the normalization of physical parameters and the treatment of boundary conditions. Several examples are presented to demonstrate the feasibility and correctness of the proposed strategy.
基金the Fundamental Research Funds for the Central Universities(DUT14RC(3)092)the National Natural Science Foundation of China(No.11272075,11472071).
文摘The basic idea of quasi-conforming method is that the strain-dis-placement equations are weakened as well as the equilibrium equations.In this paper,an 18-DOF triangular element for couple stress theory is proposed within the framework of quasi-conforming technique.The formulation starts from truncated Taylor expansion of strains and appropriate interpolation functions are chosen to calculate strain integration.This element satisfies C0 continuity with second order accuracy and weak C1 continuity simultaneously.Numerical examples demonstrate that the proposed model can pass the C0??1 patch test and has high accuracy.The element does not exhibit extra zero energy modes and can capture the scale effects of microstructure.
文摘Based on the micropolar theory(MPT),a two-dimensional(2 D)element is proposed to describe the free vibration response of structures.In the context of the MPT,a 2 D formulation is developed within the ABAQUS finite element software.The user-defined element(UEL)subroutine is used to implement a micropolar element.The micropolar effects on the vibration behavior of 2 D structures with arbitrary shapes are studied.The effect of micro-inertia becomes dominant,and by considering the micropolar effects,the frequencies decrease.Also,there is a considerable discrepancy between the predicted micropolar and classical frequencies at small scales,and this difference decreases when the side length-to-length scale ratio becomes large.
文摘A new displacement based higher order element has been formulated that is ideally suitable for shear deformable composite and sandwich plates. Suitable functions for displacements and rotations for each node have been selected so that the element shows rapid convergence, an excellent response against transverse shear loading and requires no shear correction factors. It is completely lock-free and behaves extremely well for thin to thick plates. To make the element rapidly convergent and to capture warping effects for composites, higher order displacement terms in the displacement kinematics have been considered for each node. The element has eleven degrees of freedom per node. Shear deformation has also been considered in the formulation by taking into account shear strains ( rxz and ryz) as nodal unknowns. The element is very simple to formulate and could be coded up in research software. A small Fortran code has been developed to implement the element and various examples of isotropic and composite plates have been analyzed to show the effectiveness of the element.
基金Funded by National Key Research and Development Program of China(No.2017YFB0310400)the National Natural Science Foundation of China(Nos.51872217,51932006,51972246 and 51521001)+3 种基金Fundamental Research Funds for the Central Universities in ChinaState Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),the Joint Fund(No.6141A02022255)the Major Program of the Specialized Technological Innovation of HuBei Province,China(No.2019AFA176)the“111”Project(No.B13035)。
文摘We used density functional theory(DFT)calculations to study the influence of alkali earth metal element(AE)doping on the crystal structure and electronic band structure ofα-Si3N4.The diversity of atomic radii of alkaline earth metal elements results in structural expansion when they were doped into theα-Si3N4 lattice.Formation energies of the doped structures indicate that dopants prefer to occupy the interstitial site under the nitrogen-deficient environment,while substitute Si under the nitrogen-rich environment,which provides a guide to synthesizingα-Si3N4 with different doping types by controlling nitrogen conditions.For electronic structures,energy levels of the dopants appear in the bottom of the conduction band or the top of the valence band or the forbidden band,which reduces the bandgap ofα-Si3N4.
文摘In this paper, a kind of rationalism theory of shell is established which is of different mechanic characters in tension and in compression, and the finite element numerical analysis method is also described.
文摘This paper introduces creativity,one of the significant features in maths.The creative mathematical beauty of symmetry and asymmetry are worth investigating in the practicing of Taichi.Symmetrical variances make the real world.Symmetry can be regarded as a kind of mirroring,like the line symmetry,the mirror image of the other parts,or rotational symmetry.Such characteristics can be vividly demonstrated in the traditional Chinese philosophical yin-yang theory(YY).The accompanying of male and female reveals the friendly cooperative relationship.YY reflects the counterparts of vacancy and firm,inhale and exhale,noun and verb,theory and practice,light and heavy,slow and fast,the pace,the sound effect in the classroom.Such an analysis is undergone about yin and yang in Yi School and Dao De Ching(DDC).Furthermore,there are detailed arguments of the symmetric nature of every verse of DDC,revealing the cultural value of the language.Their applications in the class admit the recognition under the new liberal arts project by China’s Ministry of Education.Yet,the integration of research and teaching is required to go further.
文摘The application of digital technology in the field of construction is still in its infancy, and the existing concrete framework of digital technology application in the construction industry and the study of applied ecological elements are not enough. The ecological elements of digital technology application in the construction industry are important factors that promote the healthy op</span><span style="font-family:Verdana;">eration of the entire digital technology application ecosystem. </span><span style="font-family:Verdana;">Using grounded theory, we compiled the data of 33 researchers who participated in </span><span style="font-family:Verdana;">semi-structured interviews, and obtained 4 main categories and 9</span><span style="font-family:Verdana;"> sub-categories of ecological elements of digital technology application in the construction industry. Among them, the digital technology application mechanism is the core category of ecological application elements. We also used the Bass model to analyze the application trend of digital technology in the construction industry. </span><span style="font-family:Verdana;">In 2040, the number of construction companies applying digital</span><span style="font-family:Verdana;"> technology will reach 98.66% of the maximum market potential.