Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials ...Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.展开更多
The isotropic and anisotropic behaviors are considered as the important formats of the constitutive behaviors,and can also be called the global properties.To improve the identification ability of virtual fields method...The isotropic and anisotropic behaviors are considered as the important formats of the constitutive behaviors,and can also be called the global properties.To improve the identification ability of virtual fields method(VFM)when the global properties are unknown,this paper proposes the strain correlation method(SCM)to determine the global properties before the parameter identification using the VFM.Firstly,the basic principle of SCM is described in detail.Then,the feasibility and accuracy of SCM are verified through the numerical experiments based on the three-point bending configuration and the real experiment of polymethyl methacrylate(PMMA).The influence of the additive Gaussian white noise,local errors in the strain fields,and missing data at the specimen edges on the characterization results are evaluated.The results show that the SCM has good noise immunity and lower accuracy requirements for the strain fields.As an application,the mechanical properties of Ti-6A1-4V alloys fabricated by selective laser melting(SLM)are characterized by the SCM.The results show that the alloys are isotropic,and the isotropic VFM is utilized to determine the mechanical parameters.By using the SCM,the accuracy of identification results can be improved for the isotropic or bidirectional reinforced orthotropic materials when using VFM.展开更多
Virtual Field Geologic Trip System (VFGTS) constructed by the technique of visualization can efficiently present geologic field information and widely used in the field of geologic education. This paper introduces the...Virtual Field Geologic Trip System (VFGTS) constructed by the technique of visualization can efficiently present geologic field information and widely used in the field of geologic education. This paper introduces the developing thinking of VFGTS and discusses the main implement processes. Building VFGTS mainly includes systemically gathering of field geological data, the building of virtual geological world, and displaying of virtual geologic world and human-computer interaction.展开更多
This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses...This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.展开更多
This highly interdisciplinary research paper discusses some new insights into the fundamentalproperties of information-rich social networks.It mainly focuses on:i)Postulating the generalproperties of an information-ba...This highly interdisciplinary research paper discusses some new insights into the fundamentalproperties of information-rich social networks.It mainly focuses on:i)Postulating the generalproperties of an information-based networking economy;ii)Modeling emergent and self-organizing featuresof social networks;iii)Discussing how to simulate complex social systems using a field-basedapproach and multi-agent platforms.Additionally,this paper gives some ideas of how to construct avirtual field-based communications network of intelligent agents using currently available computationalintelligence methods.A new simulation paradigm offers some useful concepts to transform multidimensionalfactor space(representing a multiplicity of phenomenal forms and interactions)into the mostuniversal spectral coding system.This paper gives some ideas of how not only the communicationmechanism but also the social agents can be simulated as oscillating processes.展开更多
Temperature field control of electromechanical system with constant temperature is one of the important factors that affects the accuracy of the system. Traditional ways of temperature detec- tion cost a lot but have ...Temperature field control of electromechanical system with constant temperature is one of the important factors that affects the accuracy of the system. Traditional ways of temperature detec- tion cost a lot but have low responding sensitivity. To solve this problem, temperature field simula- tion using numerical simulation was done toward the electromechanical system, and the platform temperature field distribution as well as the process of the platform reaching the steady-state was an- alyzed. The research shows that the system temperature observing parameters are all within normal range and the temperature control structure is rational. In all, the research achievements have some engineering and theoretical values in improving the design of temperature control device and system accuracy.展开更多
基金the financial support from the National Natural Science Foundation of China (Grants 11672153, 11232008, and 11227801)
文摘Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.
基金This research was financially supported by the National Key Research and Development Program of China(Grant 2017YFB1103900)the National Science and Technology Major Project(Grant 2017-VI-0003-0073)+1 种基金the National Natural Science Foundation of China(Grant 11672153)Hubei Provincial Major Program of Technological Innovation(Grant 2017AAA121).
文摘The isotropic and anisotropic behaviors are considered as the important formats of the constitutive behaviors,and can also be called the global properties.To improve the identification ability of virtual fields method(VFM)when the global properties are unknown,this paper proposes the strain correlation method(SCM)to determine the global properties before the parameter identification using the VFM.Firstly,the basic principle of SCM is described in detail.Then,the feasibility and accuracy of SCM are verified through the numerical experiments based on the three-point bending configuration and the real experiment of polymethyl methacrylate(PMMA).The influence of the additive Gaussian white noise,local errors in the strain fields,and missing data at the specimen edges on the characterization results are evaluated.The results show that the SCM has good noise immunity and lower accuracy requirements for the strain fields.As an application,the mechanical properties of Ti-6A1-4V alloys fabricated by selective laser melting(SLM)are characterized by the SCM.The results show that the alloys are isotropic,and the isotropic VFM is utilized to determine the mechanical parameters.By using the SCM,the accuracy of identification results can be improved for the isotropic or bidirectional reinforced orthotropic materials when using VFM.
文摘Virtual Field Geologic Trip System (VFGTS) constructed by the technique of visualization can efficiently present geologic field information and widely used in the field of geologic education. This paper introduces the developing thinking of VFGTS and discusses the main implement processes. Building VFGTS mainly includes systemically gathering of field geological data, the building of virtual geological world, and displaying of virtual geologic world and human-computer interaction.
基金Project supported by the National Natural Science Foundation of China (Grant No 10847143)the Natural Science Foundation of Shandong Province (Grant Nos Q2007A01 and Y2008A23)
文摘This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose-Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser.
基金supported by EU-Funded Research Project Reg. under Grant No.S-VP2-1.3-UM-01-K-01-065
文摘This highly interdisciplinary research paper discusses some new insights into the fundamentalproperties of information-rich social networks.It mainly focuses on:i)Postulating the generalproperties of an information-based networking economy;ii)Modeling emergent and self-organizing featuresof social networks;iii)Discussing how to simulate complex social systems using a field-basedapproach and multi-agent platforms.Additionally,this paper gives some ideas of how to construct avirtual field-based communications network of intelligent agents using currently available computationalintelligence methods.A new simulation paradigm offers some useful concepts to transform multidimensionalfactor space(representing a multiplicity of phenomenal forms and interactions)into the mostuniversal spectral coding system.This paper gives some ideas of how not only the communicationmechanism but also the social agents can be simulated as oscillating processes.
基金Supported by the Ministerial Level Advanced Research Foundation( 51306070123)
文摘Temperature field control of electromechanical system with constant temperature is one of the important factors that affects the accuracy of the system. Traditional ways of temperature detec- tion cost a lot but have low responding sensitivity. To solve this problem, temperature field simula- tion using numerical simulation was done toward the electromechanical system, and the platform temperature field distribution as well as the process of the platform reaching the steady-state was an- alyzed. The research shows that the system temperature observing parameters are all within normal range and the temperature control structure is rational. In all, the research achievements have some engineering and theoretical values in improving the design of temperature control device and system accuracy.
