Steps of manipulation is required to complete the m od eling of the connection elements such as bolt, pin and the like in commerce CAD system. It leads to low efficiency, difficulty to assure the relative position, im...Steps of manipulation is required to complete the m od eling of the connection elements such as bolt, pin and the like in commerce CAD system. It leads to low efficiency, difficulty to assure the relative position, impossibility to express rules and knowledge. Based on the inner character analy sis of interpart, detail modification and assembly relation of mechanical connec ting element, the idea, which extends the feature modeling of part to the interp art feature modeling for assembly purpose, is presented, and virtual part based connecting element modeling is proposed. Virtual part is a complement set of lo cal modification of part to be connected. In assembly modeling, base part is mod ified by Boolean operation between base part and virtual part. The modeling and assembly is finished just in one operation, at the same time the rules and knowl edge of the connection elements are encapsulated through virtual part. According to this mechanism, a knowledge-based connecting elements rapid design module i s developed on commerce software package UG with satisfying results.展开更多
This paper reports that a 4H-SiC MESFET （Metal Semiconductor Field Effect Transistor） large signal drain current model based on physical expressions has been developed to be used in CAD tools. The form of drain curr...This paper reports that a 4H-SiC MESFET （Metal Semiconductor Field Effect Transistor） large signal drain current model based on physical expressions has been developed to be used in CAD tools. The form of drain current model is based on semi-empirical MESFET model, and all parameters in this model are determined by physical parameters of 4H-SiC MESFET. The verification of the present model embedded in CAD tools is made, which shows a good agreement with measured data of large signal DC I-V characteristics, PAE （power added efficiency）, output power and gain.展开更多
The globalization and the intensive competition of th e automotive market require shortening the product development cycle, improving the quality and reducing the cost. Optimizing the product development process, b ui...The globalization and the intensive competition of th e automotive market require shortening the product development cycle, improving the quality and reducing the cost. Optimizing the product development process, b uilding product’s consistent defining model for life cycle, and realizing the in tegration of CAD/CAM/CAE and Concurrent Engineering (CE) become the means to acc ept the challenge. A new product modeling technology, Multi Model Technology (MM T), is provided in this paper to meet the needs of the challenge for automotive powertrain product development. First, the paper introduces the concept of Multi Model Technology. MMT introduce s Object-oriented Technology (OT) into product modeling process and combine OT with feature-based modeling technology. With the help of OT, MMT builds product object model to support system level management in product development. The obj ect model of the product is a Multi Model Structure. The MMS consists of finish part model level (assembly model level), rough part model level (part model leve l), function model level and basic model level. Every models in the MMS is creat ed by feature-based technology in design process. In this case, models in the M MS of product can be shared by casting mould, sand core and sand core mould. The refore, CAD engineers, CAE engineers and CAM engineers can work concurrently and the integration of CAD/CAM/CAE can be realized. Second, MMT is applied in cylinder head development. The multi model structures of cylinder head, its casting mould, sand core and sand core mould are built, an d the process-oriented feature models of every objects in the multi model struc tures are modeled, the application of different model objects in development pro cess is analyzed. The integrated modeling technology of cylinder head, its casti ng mould, sand core and sand core mould under MMT is studied. And the concurrent engineering oriented integration method of CAD/CAE and the method to realize th e integration of CAD/CAE under MMT are also discussed. Based on above, the integ ration of CAD/CAM/CAE of cylinder head is realized in automotive powertrain prod uct. The practice results shows that the modeling technology in this paper can optimi ze the development process, realize the data sharing and concurrent engineering in the product development process.展开更多
This paper describes multi view modeling and data model transformation for the modeling. We have proposed a reference model of CAD system generation, which can be applied to various domain specific languages. Howeve...This paper describes multi view modeling and data model transformation for the modeling. We have proposed a reference model of CAD system generation, which can be applied to various domain specific languages. However, the current CAD system generation cannot integrate data of multiple domains. Generally each domain has its own view of products. For example, in the domain of architectural structure, designers extract the necessary data from the data in architecture design. Domain experts translate one view into another view beyond domains using their own brains.The multi view modeling is a way to integrate product data of multiple domains, and make it possible to translate views among various domains by computers.展开更多
CAD model retrieval based on functional semantics is more significant than content-based 3D model retrieval during the mechanical conceptual design phase. However, relevant research is still not fully discussed. There...CAD model retrieval based on functional semantics is more significant than content-based 3D model retrieval during the mechanical conceptual design phase. However, relevant research is still not fully discussed. Therefore, a functional semantic-based CAD model annotation and retrieval method is proposed to support mechanical conceptual design and design reuse, inspire designer creativity through existing CAD models, shorten design cycle, and reduce costs. Firstly, the CAD model functional semantic ontology is constructed to formally represent the functional semantics of CAD models and describe the mechanical conceptual design space comprehensively and consistently. Secondly, an approach to represent CAD models as attributed adjacency graphs（AAG） is proposed. In this method, the geometry and topology data are extracted from STEP models. On the basis of AAG, the functional semantics of CAD models are annotated semi-automatically by matching CAD models that contain the partial features of which functional semantics have been annotated manually, thereby constructing CAD Model Repository that supports model retrieval based on functional semantics. Thirdly, a CAD model retrieval algorithm that supports multi-function extended retrieval is proposed to explore more potential creative design knowledge in the semantic level. Finally, a prototype system, called Functional Semantic-based CAD Model Annotation and Retrieval System（FSMARS）, is implemented. A case demonstrates that FSMARS can successfully botain multiple potential CAD models that conform to the desired function. The proposed research addresses actual needs and presents a new way to acquire CAD models in the mechanical conceptual design phase.展开更多
Linked tetra shaft and double cantilever flat flap gate is a new type of structure in water conservancy projects,but the traditional method is now adopted in its design.In order to the application and dissemination ...Linked tetra shaft and double cantilever flat flap gate is a new type of structure in water conservancy projects,but the traditional method is now adopted in its design.In order to the application and dissemination of the type of sluice,this paper researches the difficult points of design advance,through researching the motion locus & stress coundition of linked tetra shaft system.The writer will build up the mathmatical model and handle it with the computer.Thus,we can achieve the modern desing on the basis of the software of linked tetra shaft system development.展开更多
Cloud manufacturing is one of the three key technologies that enable intelligent manufacturing.This paper presents a novel attribute-based encryption(ABE)approach for computer-aided design(CAD)assembly models to effec...Cloud manufacturing is one of the three key technologies that enable intelligent manufacturing.This paper presents a novel attribute-based encryption(ABE)approach for computer-aided design(CAD)assembly models to effectively support hierarchical access control,integrity verification,and deformation protection for co-design scenarios in cloud manufacturing.An assembly hierarchy access tree(AHAT)is designed as the hierarchical access structure.Attribute-related ciphertext elements,which are contained in an assembly ciphertext(ACT)file,are adapted for content keys decryption instead of CAD component files.We modify the original Merkle tree(MT)and reconstruct an assembly MT.The proposed ABE framework has the ability to combine the deformation protection method with a content privacy of CAD models.The proposed encryption scheme is demonstrated to be secure under the standard assumption.Experimental simulation on typical CAD assembly models demonstrates that the proposed approach is feasible in applications.展开更多
Worm and worm gear are modeled under development environment in AutoCAD based on the principle of ordinary cylindrical worm drive. The drawing commands available in AutoCAD are used to develop worm blank and cutter mo...Worm and worm gear are modeled under development environment in AutoCAD based on the principle of ordinary cylindrical worm drive. The drawing commands available in AutoCAD are used to develop worm blank and cutter models. The solid models of worm and worm gear are obtained through the use of the commands, move, rotate and subtract, to simulate the generating cutting movement on the gear cutting machine. Autolisp language is utilized in programming for parametric modeling of worm and worm gear. The developed program can automatically draw worm and worm gear when users load the wlwg program, input the modulus and the number of threads, handedness, and other parameters. The operation is simple and accurate, providing potentials to speed up product design process and improve efficiency.展开更多
An algorithm for compensating the varying section contour within the extent of each layer thickness is proposed to improve the rapid prototyping part’s shape and size precision.
A new method for design of turbomachinery blades is presented. The parameters of a compressor blade are created from the Computational Fluid Dynamics （CFD） software CFX-BladeGen, and are inputted to the Computer Aid...A new method for design of turbomachinery blades is presented. The parameters of a compressor blade are created from the Computational Fluid Dynamics （CFD） software CFX-BladeGen, and are inputted to the Computer Aided Design （CAD） software UG for building a curve surface model to create an entity model in UG. The result shows that the blade model is favorable from the entity effect and reflection analysis and the model process is useful for the CAD model creation of turbomachinery blades.展开更多
A method to exchange digital CAD model construction history data using ISO10303 is presented. The primary intention of this research is to demonstrate the utility of ISO10303-108 in achieving parametric CAD model exch...A method to exchange digital CAD model construction history data using ISO10303 is presented. The primary intention of this research is to demonstrate the utility of ISO10303-108 in achieving parametric CAD model exchange between commercial CAD systems. ISO10303-108,still under development,has been used to represent geometric and dimensional constraints on the sketch profile. Schemas from Parts 42,50 of ISO 10303 are also used. ISO10303-42 is adopted to represent geometric and topological information and ISO10303-50 is used to represent the mathematical expression.展开更多
A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to stand...A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to standard feature opera- tion.The feature information including feature tree,dimensions and constraints,which will be lost in traditional data conver- sion,as well as geometry are converted completely from source CAD system to destination one.So the transferred model can be edit- ed through feature operation,which cannot be implemented by general model-exchange interface.展开更多
文摘Steps of manipulation is required to complete the m od eling of the connection elements such as bolt, pin and the like in commerce CAD system. It leads to low efficiency, difficulty to assure the relative position, impossibility to express rules and knowledge. Based on the inner character analy sis of interpart, detail modification and assembly relation of mechanical connec ting element, the idea, which extends the feature modeling of part to the interp art feature modeling for assembly purpose, is presented, and virtual part based connecting element modeling is proposed. Virtual part is a complement set of lo cal modification of part to be connected. In assembly modeling, base part is mod ified by Boolean operation between base part and virtual part. The modeling and assembly is finished just in one operation, at the same time the rules and knowl edge of the connection elements are encapsulated through virtual part. According to this mechanism, a knowledge-based connecting elements rapid design module i s developed on commerce software package UG with satisfying results.
文摘This paper reports that a 4H-SiC MESFET （Metal Semiconductor Field Effect Transistor） large signal drain current model based on physical expressions has been developed to be used in CAD tools. The form of drain current model is based on semi-empirical MESFET model, and all parameters in this model are determined by physical parameters of 4H-SiC MESFET. The verification of the present model embedded in CAD tools is made, which shows a good agreement with measured data of large signal DC I-V characteristics, PAE （power added efficiency）, output power and gain.
文摘The globalization and the intensive competition of th e automotive market require shortening the product development cycle, improving the quality and reducing the cost. Optimizing the product development process, b uilding product’s consistent defining model for life cycle, and realizing the in tegration of CAD/CAM/CAE and Concurrent Engineering (CE) become the means to acc ept the challenge. A new product modeling technology, Multi Model Technology (MM T), is provided in this paper to meet the needs of the challenge for automotive powertrain product development. First, the paper introduces the concept of Multi Model Technology. MMT introduce s Object-oriented Technology (OT) into product modeling process and combine OT with feature-based modeling technology. With the help of OT, MMT builds product object model to support system level management in product development. The obj ect model of the product is a Multi Model Structure. The MMS consists of finish part model level (assembly model level), rough part model level (part model leve l), function model level and basic model level. Every models in the MMS is creat ed by feature-based technology in design process. In this case, models in the M MS of product can be shared by casting mould, sand core and sand core mould. The refore, CAD engineers, CAE engineers and CAM engineers can work concurrently and the integration of CAD/CAM/CAE can be realized. Second, MMT is applied in cylinder head development. The multi model structures of cylinder head, its casting mould, sand core and sand core mould are built, an d the process-oriented feature models of every objects in the multi model struc tures are modeled, the application of different model objects in development pro cess is analyzed. The integrated modeling technology of cylinder head, its casti ng mould, sand core and sand core mould under MMT is studied. And the concurrent engineering oriented integration method of CAD/CAE and the method to realize th e integration of CAD/CAE under MMT are also discussed. Based on above, the integ ration of CAD/CAM/CAE of cylinder head is realized in automotive powertrain prod uct. The practice results shows that the modeling technology in this paper can optimi ze the development process, realize the data sharing and concurrent engineering in the product development process.
文摘This paper describes multi view modeling and data model transformation for the modeling. We have proposed a reference model of CAD system generation, which can be applied to various domain specific languages. However, the current CAD system generation cannot integrate data of multiple domains. Generally each domain has its own view of products. For example, in the domain of architectural structure, designers extract the necessary data from the data in architecture design. Domain experts translate one view into another view beyond domains using their own brains.The multi view modeling is a way to integrate product data of multiple domains, and make it possible to translate views among various domains by computers.
基金Supported by National Natural Science Foundation of China (Grant No.51175287)National Science and Technology Major Project of China (Grant No.2011ZX02403)
文摘CAD model retrieval based on functional semantics is more significant than content-based 3D model retrieval during the mechanical conceptual design phase. However, relevant research is still not fully discussed. Therefore, a functional semantic-based CAD model annotation and retrieval method is proposed to support mechanical conceptual design and design reuse, inspire designer creativity through existing CAD models, shorten design cycle, and reduce costs. Firstly, the CAD model functional semantic ontology is constructed to formally represent the functional semantics of CAD models and describe the mechanical conceptual design space comprehensively and consistently. Secondly, an approach to represent CAD models as attributed adjacency graphs（AAG） is proposed. In this method, the geometry and topology data are extracted from STEP models. On the basis of AAG, the functional semantics of CAD models are annotated semi-automatically by matching CAD models that contain the partial features of which functional semantics have been annotated manually, thereby constructing CAD Model Repository that supports model retrieval based on functional semantics. Thirdly, a CAD model retrieval algorithm that supports multi-function extended retrieval is proposed to explore more potential creative design knowledge in the semantic level. Finally, a prototype system, called Functional Semantic-based CAD Model Annotation and Retrieval System（FSMARS）, is implemented. A case demonstrates that FSMARS can successfully botain multiple potential CAD models that conform to the desired function. The proposed research addresses actual needs and presents a new way to acquire CAD models in the mechanical conceptual design phase.
文摘Linked tetra shaft and double cantilever flat flap gate is a new type of structure in water conservancy projects,but the traditional method is now adopted in its design.In order to the application and dissemination of the type of sluice,this paper researches the difficult points of design advance,through researching the motion locus & stress coundition of linked tetra shaft system.The writer will build up the mathmatical model and handle it with the computer.Thus,we can achieve the modern desing on the basis of the software of linked tetra shaft system development.
基金supported by the National Natural Science Foundation of China(62072348)the Science and Technology Major Project of Hubei Province(Next-Generation AI Technologies,2019AEA170).
文摘Cloud manufacturing is one of the three key technologies that enable intelligent manufacturing.This paper presents a novel attribute-based encryption(ABE)approach for computer-aided design(CAD)assembly models to effectively support hierarchical access control,integrity verification,and deformation protection for co-design scenarios in cloud manufacturing.An assembly hierarchy access tree(AHAT)is designed as the hierarchical access structure.Attribute-related ciphertext elements,which are contained in an assembly ciphertext(ACT)file,are adapted for content keys decryption instead of CAD component files.We modify the original Merkle tree(MT)and reconstruct an assembly MT.The proposed ABE framework has the ability to combine the deformation protection method with a content privacy of CAD models.The proposed encryption scheme is demonstrated to be secure under the standard assumption.Experimental simulation on typical CAD assembly models demonstrates that the proposed approach is feasible in applications.
文摘Worm and worm gear are modeled under development environment in AutoCAD based on the principle of ordinary cylindrical worm drive. The drawing commands available in AutoCAD are used to develop worm blank and cutter models. The solid models of worm and worm gear are obtained through the use of the commands, move, rotate and subtract, to simulate the generating cutting movement on the gear cutting machine. Autolisp language is utilized in programming for parametric modeling of worm and worm gear. The developed program can automatically draw worm and worm gear when users load the wlwg program, input the modulus and the number of threads, handedness, and other parameters. The operation is simple and accurate, providing potentials to speed up product design process and improve efficiency.
基金Supported by College Science Foundation of Jiangsu(07KJB460113)
文摘An algorithm for compensating the varying section contour within the extent of each layer thickness is proposed to improve the rapid prototyping part’s shape and size precision.
文摘A new method for design of turbomachinery blades is presented. The parameters of a compressor blade are created from the Computational Fluid Dynamics （CFD） software CFX-BladeGen, and are inputted to the Computer Aided Design （CAD） software UG for building a curve surface model to create an entity model in UG. The result shows that the blade model is favorable from the entity effect and reflection analysis and the model process is useful for the CAD model creation of turbomachinery blades.
文摘A method to exchange digital CAD model construction history data using ISO10303 is presented. The primary intention of this research is to demonstrate the utility of ISO10303-108 in achieving parametric CAD model exchange between commercial CAD systems. ISO10303-108,still under development,has been used to represent geometric and dimensional constraints on the sketch profile. Schemas from Parts 42,50 of ISO 10303 are also used. ISO10303-42 is adopted to represent geometric and topological information and ISO10303-50 is used to represent the mathematical expression.
基金Supported by Science & Technology Sponsoring Project of Ministry of Education(105161)
文摘A model-exchange method based on feature between isomerous CAD systems is put forward in this paper.In this method,CAD model information is accessed at both feature and geometry levels and converted according to standard feature opera- tion.The feature information including feature tree,dimensions and constraints,which will be lost in traditional data conver- sion,as well as geometry are converted completely from source CAD system to destination one.So the transferred model can be edit- ed through feature operation,which cannot be implemented by general model-exchange interface.
