2000 Vol.13(2)
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2000, 14(2).
Abstract:
The design and management of the objects about the numerical manifold method are studied by abstracting the finite cover system of numerical manifold method as independent data classes and the theoretical basis for the researching and expanding of numerical manifold method is also put forward.The Hammer integration of triangular area coordinates is used in the integration of the element.The calculation result shows that the program is accuracy and effective.
The design and management of the objects about the numerical manifold method are studied by abstracting the finite cover system of numerical manifold method as independent data classes and the theoretical basis for the researching and expanding of numerical manifold method is also put forward.The Hammer integration of triangular area coordinates is used in the integration of the element.The calculation result shows that the program is accuracy and effective.
2000, 14(2).
Abstract:
After brief describing the principle of wavelet transform(WT)of signals,a new signals analysis system based on wavelet transform is introduced.The design and development of the instrument of wavelet transform are described.A number of practical uses of this system demonstrate that wavelet transform system is specially functional in identifying and processing impulse,singular and non-smooth signals,so that is should be evaluated the most advanced signal analyzing system.
After brief describing the principle of wavelet transform(WT)of signals,a new signals analysis system based on wavelet transform is introduced.The design and development of the instrument of wavelet transform are described.A number of practical uses of this system demonstrate that wavelet transform system is specially functional in identifying and processing impulse,singular and non-smooth signals,so that is should be evaluated the most advanced signal analyzing system.
2000, 14(2).
Abstract:
A technique for compensating the errors of coordinate measuring machines(CMMs)with low stiffness is proposed.Some additional items related with the force deformation are introduced to the error compensation equations.The research was carried on a moving column horizontal arm CMM.Experimental results show that both the effects of systematic components of error motions and force deformations are greatly reduced,which shows the effectiveness of proposed technique.
A technique for compensating the errors of coordinate measuring machines(CMMs)with low stiffness is proposed.Some additional items related with the force deformation are introduced to the error compensation equations.The research was carried on a moving column horizontal arm CMM.Experimental results show that both the effects of systematic components of error motions and force deformations are greatly reduced,which shows the effectiveness of proposed technique.
2000, 14(2).
Abstract:
On the research of assembly modeling of mechanical products,current CAD systems can only support the design process of component-to-assembly.It is diffcult to realize the design process of assembly-to-component.The theory of self-organizing assembly modeling based on relational constraints is proposed,which implements the product design of assembly-to-componet commencing with conceptual design and supporting abstract design and step-nice refinement design.
On the research of assembly modeling of mechanical products,current CAD systems can only support the design process of component-to-assembly.It is diffcult to realize the design process of assembly-to-component.The theory of self-organizing assembly modeling based on relational constraints is proposed,which implements the product design of assembly-to-componet commencing with conceptual design and supporting abstract design and step-nice refinement design.
2000, 14(2).
Abstract:
As the main componet of computer integrated manufacturing system(CIMS),flexble manufacturing system(FMS)should be an open system with reusability and extendibility.Moreover,as FMS is a complex asynchronous concurrent system,its model also should have the abilities to express the concurrency in the system and to analyze the behavior of the system.It is difficult to use any one method to model such a complex system as FMS.A modeling method using object-oriented modeling language-unified modeling language(UML)and object-oriented Petri nets(OPNs)is proposed.Class diagram in UML is used to represent the static relations among the objects in FMS.OPNs are used to model the dynamic behavior of the object and conduct performance analysis.OPNs also can be used to identify the attributes and operations of the objects.The model can describe the system integrally and can be used to design FMS control software naturally.
As the main componet of computer integrated manufacturing system(CIMS),flexble manufacturing system(FMS)should be an open system with reusability and extendibility.Moreover,as FMS is a complex asynchronous concurrent system,its model also should have the abilities to express the concurrency in the system and to analyze the behavior of the system.It is difficult to use any one method to model such a complex system as FMS.A modeling method using object-oriented modeling language-unified modeling language(UML)and object-oriented Petri nets(OPNs)is proposed.Class diagram in UML is used to represent the static relations among the objects in FMS.OPNs are used to model the dynamic behavior of the object and conduct performance analysis.OPNs also can be used to identify the attributes and operations of the objects.The model can describe the system integrally and can be used to design FMS control software naturally.
2000, 14(2).
Abstract:
The transferability of the toughness results in ductile-brittle transition region for welded crackde specimens is conducted by 3D FE analysis.The fracture toughness values for the double edge notched tension specimens are predicted effectively from the bend test results based on the local approach considering stable crack growth.It is found that the cell model gives a good description of the stable crack growth behavior,and the local approach is useful for the transferability analysis of fracture toughness results in ductile-brittle transition region.
The transferability of the toughness results in ductile-brittle transition region for welded crackde specimens is conducted by 3D FE analysis.The fracture toughness values for the double edge notched tension specimens are predicted effectively from the bend test results based on the local approach considering stable crack growth.It is found that the cell model gives a good description of the stable crack growth behavior,and the local approach is useful for the transferability analysis of fracture toughness results in ductile-brittle transition region.
2000, 14(2).
Abstract:
How to automatically generate three-dimensional finite element Delaunay mesh by a perfected node connection method is introduced,where nodes are generated based on existion elements,instead of independence of node creation and elements generation in traditional node connection method.Therefore,the the difficulty about how to automatically create nodes in the traditional method is overcome.
How to automatically generate three-dimensional finite element Delaunay mesh by a perfected node connection method is introduced,where nodes are generated based on existion elements,instead of independence of node creation and elements generation in traditional node connection method.Therefore,the the difficulty about how to automatically create nodes in the traditional method is overcome.
2000, 14(2).
Abstract:
A dynamic analysis approach to investigate the state of load distribution among contact bearings of double circular arc helical gears is proposed and a computer program is developed for calculating the factor of load distribution based on the theory of W-N gears.The changing situations of load distribution among conrtact bearings of the gears influenced by main issues are analyzed by a series of parametric studies.
A dynamic analysis approach to investigate the state of load distribution among contact bearings of double circular arc helical gears is proposed and a computer program is developed for calculating the factor of load distribution based on the theory of W-N gears.The changing situations of load distribution among conrtact bearings of the gears influenced by main issues are analyzed by a series of parametric studies.
2000, 14(2).
Abstract:
The nanoindentation fracture of multilayer hard coatings,such as TiN,TiN/Ti(C,N)/TiC,TiN/Ti(C,N)/TiC/Ti(C,N)/TiC and TiN/Ti(C,N)/TiC/Ti(C,N)/TiC/Ti(C,N)/TiC coatings,deposited on cemented carbide using a CVD technique are studied.It is found that these coatings have high hardness.Based on the analysis of the energy release in cracking,the fracture toughness of these coatings are calculated.The observations clearly establish a step occurs in the force-displacement curves at the onset of coating fracture and a straight line segment in the load-penetration depth squared curves to identify the interfacial failure of coatings.The hardness,fracture toughness and anti-wearability of these coatings are clearly compared.The results show that with the layers increasing,the fracture toughness and anti-wearability are getting larger.
The nanoindentation fracture of multilayer hard coatings,such as TiN,TiN/Ti(C,N)/TiC,TiN/Ti(C,N)/TiC/Ti(C,N)/TiC and TiN/Ti(C,N)/TiC/Ti(C,N)/TiC/Ti(C,N)/TiC coatings,deposited on cemented carbide using a CVD technique are studied.It is found that these coatings have high hardness.Based on the analysis of the energy release in cracking,the fracture toughness of these coatings are calculated.The observations clearly establish a step occurs in the force-displacement curves at the onset of coating fracture and a straight line segment in the load-penetration depth squared curves to identify the interfacial failure of coatings.The hardness,fracture toughness and anti-wearability of these coatings are clearly compared.The results show that with the layers increasing,the fracture toughness and anti-wearability are getting larger.
INVESTIGATION ON THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO THE SPIRAL GROOVED THRUST BEARING
2000, 14(2).
Abstract:
An application of the boundary element method(BEM)is presented to calculate the behaviors of a spiral grooved thrust bearing(SGTB).The basic reason is that the SGTB has very complex boundary conditions that can hinder the effective or sufficient applications of the finite difference method(FDM)and he finite element method(FEM),despite some existing work based on the FDM and the FEM.In order to apply the BEM,the pressure control equation,I.e.,Reyonolds'eqution,is first transformed into Laplace's and Poisson's equations.Discretization of the SGTB with a set of boundary elements is thus explained in detail,which also includes the handling of boundary conditions.The Archimedean SGTB is chosen as an example of the application of BEM,and the relationship between the behaviors and structure parameters of the bearing are found and discussed thuough this calculation.The obtained results lay a solid foundation for a further work of the design of the SGTB.
An application of the boundary element method(BEM)is presented to calculate the behaviors of a spiral grooved thrust bearing(SGTB).The basic reason is that the SGTB has very complex boundary conditions that can hinder the effective or sufficient applications of the finite difference method(FDM)and he finite element method(FEM),despite some existing work based on the FDM and the FEM.In order to apply the BEM,the pressure control equation,I.e.,Reyonolds'eqution,is first transformed into Laplace's and Poisson's equations.Discretization of the SGTB with a set of boundary elements is thus explained in detail,which also includes the handling of boundary conditions.The Archimedean SGTB is chosen as an example of the application of BEM,and the relationship between the behaviors and structure parameters of the bearing are found and discussed thuough this calculation.The obtained results lay a solid foundation for a further work of the design of the SGTB.
2000, 14(2).
Abstract:
In accordance with the difficult problems of belt cross viburations and effects of belt tension on machine spindle precision in abrasive belt grinding,a new soft grinding wheel is put forward,which is provided with the advantages of belt grinding and can be installed directly on the grinding machine spindle substituing for common grinding wheels.The new soft grinding whlle does not need any ancillary facilities and dressing devices in grinding.With analyzing error of wheel and grinding experiment,the high-efficiency griding characteristics grinding hard-brittle materials has been obtained.
In accordance with the difficult problems of belt cross viburations and effects of belt tension on machine spindle precision in abrasive belt grinding,a new soft grinding wheel is put forward,which is provided with the advantages of belt grinding and can be installed directly on the grinding machine spindle substituing for common grinding wheels.The new soft grinding whlle does not need any ancillary facilities and dressing devices in grinding.With analyzing error of wheel and grinding experiment,the high-efficiency griding characteristics grinding hard-brittle materials has been obtained.
2000, 14(2).
Abstract:
Research situation of concurrent tolerance design has been analyzed.As fuzzy factors are objective and unavoidable in concurrent tolerance design,fuzzy optimization theory is applied in the design.A new mathematical model of concurrent tolerance design is constructed.
Research situation of concurrent tolerance design has been analyzed.As fuzzy factors are objective and unavoidable in concurrent tolerance design,fuzzy optimization theory is applied in the design.A new mathematical model of concurrent tolerance design is constructed.
2000, 14(2).
Abstract:
In order to study the mechanism of vacuum fluxless soldering on the conditions of laser heating,the method of measuring temperature by the thermocouple is used to analyze the spreading and wetting process of both fluxless Sn-Pb solder in the vavuum surroundings and flux Sn-Pb solder on Cu pad.Solder spreading and wetting affected by the soldering thermal process is also discussed according to the thermodynamics principle.Results show that vacuum fluxless soldering demands higher temperature,and the fall of the solder surface tension is the important factor achieving fluxless laser soldering.
In order to study the mechanism of vacuum fluxless soldering on the conditions of laser heating,the method of measuring temperature by the thermocouple is used to analyze the spreading and wetting process of both fluxless Sn-Pb solder in the vavuum surroundings and flux Sn-Pb solder on Cu pad.Solder spreading and wetting affected by the soldering thermal process is also discussed according to the thermodynamics principle.Results show that vacuum fluxless soldering demands higher temperature,and the fall of the solder surface tension is the important factor achieving fluxless laser soldering.
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