In order to study the viscoelastic characteristics of asphalt mixtures in the whole-frequency range, a dynamic shearing rheometer is used to carry out dynamic frequency sweeps for asphalt mixtures, which obtains the t...In order to study the viscoelastic characteristics of asphalt mixtures in the whole-frequency range, a dynamic shearing rheometer is used to carry out dynamic frequency sweeps for asphalt mixtures, which obtains the three-dimensional relationships among G^＊, temperature and frequency. Then the time-temperature shift principle is used to translate the relationships from three dimensions to two dimensions, so master curves are obtained regarding dynamic modules changing along with the frequency over 15 amount levels. The Christensen- Anderson-Marasteanu （CAM） model, a kind of the rheological model, is used to analyze and compare rheological performances of several asphalt mixtures based on the obtained master curves. The results indicate that the dynamic theological test is an effective method for obtaining the master curve. Besides, the CAM model can describe well the viscoelastic deformation characteristics of asphalt mixtures.展开更多
A method of combining the valve system program with the engine cycle modeling software to form a full set of working process modeling is submitted,not only considering the system as an independent part,but also as a p...A method of combining the valve system program with the engine cycle modeling software to form a full set of working process modeling is submitted,not only considering the system as an independent part,but also as a part of working process to evaluate comprehensively and indicate directly if the design is good or not.The designers can optimize the design by changing the engine structure,operation and the basic parameters of the cam on condition that the sysem should be stable so as to save large amounts of time and cost.Practical examples show that such a software package is an effective tool in optimizing the valve systems and performance of the machine.展开更多
In this paper, a critical state based thermo-elasto-plastic constitutive model is developed for destructured, naturally structured and artificially structured saturated clays. The model is an extension of the previous...In this paper, a critical state based thermo-elasto-plastic constitutive model is developed for destructured, naturally structured and artificially structured saturated clays. The model is an extension of the previously developed thermo-mechanical model by the authors for saturated clays, considering the effects of structure on the mechanical behaviors of the soil. It is based on change in the position of normal consolidation line(NCL) in a compression plane(e-ln p′) due to the soil’s structure and variation of temperature. The present model is able to simulate the mechanical behavior of structured saturated clays in a triaxial plane at elevated temperatures lower than the boiling point of water. An attempt has been made to use the lowest possible number of parameters compared with that of Came Clay model and to ensure that these new parameters have clear physical interpretations. The sufficiency of the model was verified by the test results on artificially and naturally structured soils using thermal triaxial tests.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
Tolerance is imperative for seamless integration of CAD/CAM(Computer Aided Disign/Computer Aided Manufacture) which is just a text attribute and has no semantics in present CAD systems. There are many tolerance types,...Tolerance is imperative for seamless integration of CAD/CAM(Computer Aided Disign/Computer Aided Manufacture) which is just a text attribute and has no semantics in present CAD systems. There are many tolerance types, the relations between which are very complicated. In addition, the different principles of tolerance make study of tolerance difficult; and there may be various meanings or interpretation for the same type of tolerance because of the literal definition. In this work, latest unambiguous mathematical definition was applied to study, explain and clarify: (1) the formation and representation of tolerance zone, and (2) the formation and representation of variational elements; after which, the mathematical models of symmetry of different tolerance principles and different interpretations were derived. An example is given to illustrate the application of these models in tolerance analysis.展开更多
A slotting method for cosine gears was proposed by using the involute cutter based on the conjugate theories of digital surface and gear meshing. The slotting model between the cosine tooth surface represented by disc...A slotting method for cosine gears was proposed by using the involute cutter based on the conjugate theories of digital surface and gear meshing. The slotting model between the cosine tooth surface represented by discrete points and the cutter figuration determined by analytic function was built for their geometrical relationship and conjugate motion during the machining process. Conjugate points in the cutter section corresponding to the discrete points on the cosine gear tooth surface and the conjugate movements were solved. By using the flexible control of the CNC procedure, the active control of the cutting trace of the slotting cutter was accomplished and the envelop forming of the cosine gear was obtained. Based on the software C++ and Matlab, the computer aided manufacturing(CAM) system of the cosine gear was developed, and the simulation of the slotting process was accomplished. Several examples were provided to illustrate the approach. The result of the simulation demonstrates that the proposed slotting method is feasible.展开更多
A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existingmodel for saturated clays originally proposed by the authors. The saturated clays model was formulatedin the framework o...A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existingmodel for saturated clays originally proposed by the authors. The saturated clays model was formulatedin the framework of critical state soil mechanics and modified Cam-clay model. The existing model hasbeen generalized to simulate the experimentally observed behavior of unsaturated clays by introducingBishop＇s stress and suction as independent stress parameters and modifying the hardening rule and yieldcriterion to take into account the role of suction. Also, according to previous studies, an increase intemperature causes a reduction in specific volume. A reduction in suction （wetting） for a given confiningstress may induce an irreversible volumetric compression （collapse）. Thus an increase in suction （drying）raises a specific volume i.e. the movement of normal consolidation line （NCL） to higher values of voidratio. However, some experimental data confirm the assumption that this reduction is dependent on thestress level of soil element. A generalized approach considering the effect of stress level on themagnitude of clays thermal dependency in compression plane is proposed in this study. The number ofmodeling parameters is kept to a minimum, and they all have clear physical interpretations, to facilitatethe usefulness of model for practical applications. A step-by-step procedure used for parameter calibrationis also described. The model is finally evaluated using a comprehensive set of experimental datafor the thermo-mechanical behavior of unsaturated soils.2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
Considering grinding a cam with numerical control（NC）cam grinder,a mathematical model should be estab- lished with the unified parameter based on the original cam-lobe lift data to describe the movement of wheel and...Considering grinding a cam with numerical control（NC）cam grinder,a mathematical model should be estab- lished with the unified parameter based on the original cam-lobe lift data to describe the movement of wheel and establish the relation between the wheel center coordinate,the measuring angle and workpiece’s spindle rotation angle.By analyzing,the grinding wheel can be regarded as different followers.To the planar and roller followers,different mathematical models are established, but they can be unified in Eqs.（17）of this paper with the different value of the roller radius r<sub>1</sub>.And also the model is suit for the edged follower when assuming the roller radius r<sub>1</sub>=0.Experimental verification was done with TKM120 CNC/CBN grinder with NC sets’ interpolation according to the model,which shows that high precision parts can be manufactured and this mathemat- ical model can be practically applied for NC cam grinder.展开更多
The manufacturing course of blade-root precise mill for processing the blade installing notch on rotors and the corresponding mathematical model are introduced. The reliability of this mathematical model is illustrate...The manufacturing course of blade-root precise mill for processing the blade installing notch on rotors and the corresponding mathematical model are introduced. The reliability of this mathematical model is illustrated by a practical example.展开更多
Because a ship model surface (SMS) is a large double-curved 3-D surface,the machining efficiency of the cur- rent handcraft manufacturing method are very low,and the precision is difficult to control also.In order to ...Because a ship model surface (SMS) is a large double-curved 3-D surface,the machining efficiency of the cur- rent handcraft manufacturing method are very low,and the precision is difficult to control also.In order to greatly improve the machining efficiency and precision of SMS,based on the CAD/CAM/CNC technology,this paper proposed a model of SMS digi- tal manufacturing system,which is composed of five functional modules (preprocess module,CAD module,CAM module,post- process module and CNC module),and a twin-skeg SMS as an example,the key technologies & design principle of the nodtules were investigated also Based on the above research works,the first set of 4-axis SMS Digital Manufacturing System in China has been successfully developed,which can reduce the machining time of the twin-skeg SMS from 30 working days needed for the cur- rent handcrafting manufacturing method to 8 hours now,and which can control more effectively the precision of SMS also.展开更多
GS CAD98, a feature based parametric product modeling system that facilitates dexterous manipulation of mechanical design is presented. The system allows designer to make substantial changes to a part or assembly at...GS CAD98, a feature based parametric product modeling system that facilitates dexterous manipulation of mechanical design is presented. The system allows designer to make substantial changes to a part or assembly at any time during the design process. User can develop his/her own special CAD system with the help of GS CADS98s macro language PPL or kernel routines. Furthermore, it is flexible enough to exchange product data with other CAD/CAE/CAM systems according to neutral file. GS CAD98s product data is managed by an object oriented database management system called OSCAR, and the product model is built according to the standard STEP. As a result of the unified product model, all product data are globally associated in GS CAD98. GS CAD98 supports the integration with CAPP, CAM and PDM.展开更多
Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequen...Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequent manufacturing activities such as CAPP and CAM. A new design approach using feature technique and object oriented programming method is put forward in this paper in order to create the product information model of welding structure. With this approach, the product information model is able to effectively support computer aided welding process planning, fixturing, assembling, path planning of welding robot and other manufacturing activities. The feature classification and representing scheme of welding structure are discussed. A prototype system is developed based on feature and object oriented programming. Its structure and functions are given in detail.展开更多
Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of g...Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of geometric accuracy and surface finish, can be enhanced by using the product manufacturing information(PMI) stored in the neutral standard for the exchange of product model data(STEP) file, thereby integrating design and manufacturing. The present paper proposes a unique fixture design approach, to extract the geometry information from STEP application protocol(AP) 242 files of computer aided design(CAD) models, for providing automatic suggestions of locator positions and clamping surfaces. Automatic feature extraction software "FiXplan", developed using the programming language C#, is used to extract the part feature, dimension and geometry information. The information from the STEP AP 242 file is deduced using geometric reasoning techniques, which in turn is utilized for fixture planning. The developed software is observed to be adept in identifying the primary, secondary, and tertiary locating faces and locator position configurations of prismatic components. Structural analysis of the prismatic part under different locator positions was performed using commercial finite element method software, ABAQUS, and the optimized locator position was identified on the basis of minimum deformation of the workpiece.The area-ratio(base locator enclosed area(%)/work piece base area(%)) for the ideal locator configuration was observed as 33%. Experiments were conducted on a prismatic workpiece using a specially designed fixture, for different locator configurations. The surface roughness and waviness of the machined surfaces were analysed using an Alicona non-contact optical profilometer. The best surface characteristics were obtained for the surface machined under the ideal locator positions having an area-ratio of 33%, thus validating the predicted numerical results. The efficiency, capability and applicability of the developed software is demonstrated for the finishing operation of a sensor cover – a typical prismatic component having applications in the naval industry, under different locator configurations.The best results were obtained under the proposed ideal locator configuration of area-ratio 33%.展开更多
How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ...How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ADAMS is applied in dynamic simulation to fulfill the complex calculation of mechanical characteristics. Satisfactory simulation results can be obtained by iteratively refining parameters of the model, and it is shown that this scheme can be used to provide a good basis for optimum design of VCB.展开更多
In conformity with the principle of Design for Manufacture,feature-based design strate- (?)es have been developed.As the“feature”is relevant to the“macro process plan”and“macro NC programs”,obviously,“feature”...In conformity with the principle of Design for Manufacture,feature-based design strate- (?)es have been developed.As the“feature”is relevant to the“macro process plan”and“macro NC programs”,obviously,“feature”is beyond the power of conventional solid modellers.Neverthe- less,substantial breakthrough has not been made in the solid modeling field,except“feature at- taching”or“feature recognizing”methods have been taken on.In this paper,the theory, concepts,system architecture,and algorithm principles of solid modeling tool system have been represented.The practice of Feature Solid Modeling Tool System (FSMTS) developed at Huazhong University has proved that the tool may be a new foundation of Feature-Based Design.展开更多
The chicken chorioallantoic membrane (CAM) is a classical in vivo biological model in studies of angiogenesis. Combined with the right tumor system and experimental configuration this classical model can offer new app...The chicken chorioallantoic membrane (CAM) is a classical in vivo biological model in studies of angiogenesis. Combined with the right tumor system and experimental configuration this classical model can offer new approaches to investigating tumor processes. The increase in development of biotechnolo- gical devices for cancer diagnosis and treatment, calls for more sophisticated tumor models that can easily adapt to the technology, and provide a more accurate, stable and consistent platform for rapid quantitative and qualitative analysis. As we discuss a variety of applications of this novel in vivo tumor spheroid based shell-less CAM model in biomedical engineering research, we will show that it is extremely versatile and easily adaptable to an array of biomedical applications. The model is particularly useful in quantitative studies of the progression of avascular tumors into vascularized tumors in the CAM. Its environment is more stable, flat and has a large working area and wider field of view excellent for imaging and longitudinal studies. Finally, rapid data acquisition, screening and validation of biomedical devices and therapeutics are possible with the short experimental window.展开更多
针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造...针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。展开更多
基金The National Natural Science Foundation of China (No.50278037)
文摘In order to study the viscoelastic characteristics of asphalt mixtures in the whole-frequency range, a dynamic shearing rheometer is used to carry out dynamic frequency sweeps for asphalt mixtures, which obtains the three-dimensional relationships among G^＊, temperature and frequency. Then the time-temperature shift principle is used to translate the relationships from three dimensions to two dimensions, so master curves are obtained regarding dynamic modules changing along with the frequency over 15 amount levels. The Christensen- Anderson-Marasteanu （CAM） model, a kind of the rheological model, is used to analyze and compare rheological performances of several asphalt mixtures based on the obtained master curves. The results indicate that the dynamic theological test is an effective method for obtaining the master curve. Besides, the CAM model can describe well the viscoelastic deformation characteristics of asphalt mixtures.
文摘A method of combining the valve system program with the engine cycle modeling software to form a full set of working process modeling is submitted,not only considering the system as an independent part,but also as a part of working process to evaluate comprehensively and indicate directly if the design is good or not.The designers can optimize the design by changing the engine structure,operation and the basic parameters of the cam on condition that the sysem should be stable so as to save large amounts of time and cost.Practical examples show that such a software package is an effective tool in optimizing the valve systems and performance of the machine.
文摘In this paper, a critical state based thermo-elasto-plastic constitutive model is developed for destructured, naturally structured and artificially structured saturated clays. The model is an extension of the previously developed thermo-mechanical model by the authors for saturated clays, considering the effects of structure on the mechanical behaviors of the soil. It is based on change in the position of normal consolidation line(NCL) in a compression plane(e-ln p′) due to the soil’s structure and variation of temperature. The present model is able to simulate the mechanical behavior of structured saturated clays in a triaxial plane at elevated temperatures lower than the boiling point of water. An attempt has been made to use the lowest possible number of parameters compared with that of Came Clay model and to ensure that these new parameters have clear physical interpretations. The sufficiency of the model was verified by the test results on artificially and naturally structured soils using thermal triaxial tests.
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Tolerance is imperative for seamless integration of CAD/CAM(Computer Aided Disign/Computer Aided Manufacture) which is just a text attribute and has no semantics in present CAD systems. There are many tolerance types, the relations between which are very complicated. In addition, the different principles of tolerance make study of tolerance difficult; and there may be various meanings or interpretation for the same type of tolerance because of the literal definition. In this work, latest unambiguous mathematical definition was applied to study, explain and clarify: (1) the formation and representation of tolerance zone, and (2) the formation and representation of variational elements; after which, the mathematical models of symmetry of different tolerance principles and different interpretations were derived. An example is given to illustrate the application of these models in tolerance analysis.
基金Projects(51205335,50975242,51375411) supported by the National Natural Science Foundation of ChinaProject(2013J01209) supported by the Natural Science Foundation of Fujian Province,China
文摘A slotting method for cosine gears was proposed by using the involute cutter based on the conjugate theories of digital surface and gear meshing. The slotting model between the cosine tooth surface represented by discrete points and the cutter figuration determined by analytic function was built for their geometrical relationship and conjugate motion during the machining process. Conjugate points in the cutter section corresponding to the discrete points on the cosine gear tooth surface and the conjugate movements were solved. By using the flexible control of the CNC procedure, the active control of the cutting trace of the slotting cutter was accomplished and the envelop forming of the cosine gear was obtained. Based on the software C++ and Matlab, the computer aided manufacturing(CAM) system of the cosine gear was developed, and the simulation of the slotting process was accomplished. Several examples were provided to illustrate the approach. The result of the simulation demonstrates that the proposed slotting method is feasible.
文摘A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existingmodel for saturated clays originally proposed by the authors. The saturated clays model was formulatedin the framework of critical state soil mechanics and modified Cam-clay model. The existing model hasbeen generalized to simulate the experimentally observed behavior of unsaturated clays by introducingBishop＇s stress and suction as independent stress parameters and modifying the hardening rule and yieldcriterion to take into account the role of suction. Also, according to previous studies, an increase intemperature causes a reduction in specific volume. A reduction in suction （wetting） for a given confiningstress may induce an irreversible volumetric compression （collapse）. Thus an increase in suction （drying）raises a specific volume i.e. the movement of normal consolidation line （NCL） to higher values of voidratio. However, some experimental data confirm the assumption that this reduction is dependent on thestress level of soil element. A generalized approach considering the effect of stress level on themagnitude of clays thermal dependency in compression plane is proposed in this study. The number ofmodeling parameters is kept to a minimum, and they all have clear physical interpretations, to facilitatethe usefulness of model for practical applications. A step-by-step procedure used for parameter calibrationis also described. The model is finally evaluated using a comprehensive set of experimental datafor the thermo-mechanical behavior of unsaturated soils.2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
文摘Considering grinding a cam with numerical control（NC）cam grinder,a mathematical model should be estab- lished with the unified parameter based on the original cam-lobe lift data to describe the movement of wheel and establish the relation between the wheel center coordinate,the measuring angle and workpiece’s spindle rotation angle.By analyzing,the grinding wheel can be regarded as different followers.To the planar and roller followers,different mathematical models are established, but they can be unified in Eqs.（17）of this paper with the different value of the roller radius r<sub>1</sub>.And also the model is suit for the edged follower when assuming the roller radius r<sub>1</sub>=0.Experimental verification was done with TKM120 CNC/CBN grinder with NC sets’ interpolation according to the model,which shows that high precision parts can be manufactured and this mathemat- ical model can be practically applied for NC cam grinder.
文摘The manufacturing course of blade-root precise mill for processing the blade installing notch on rotors and the corresponding mathematical model are introduced. The reliability of this mathematical model is illustrated by a practical example.
文摘Because a ship model surface (SMS) is a large double-curved 3-D surface,the machining efficiency of the cur- rent handcraft manufacturing method are very low,and the precision is difficult to control also.In order to greatly improve the machining efficiency and precision of SMS,based on the CAD/CAM/CNC technology,this paper proposed a model of SMS digi- tal manufacturing system,which is composed of five functional modules (preprocess module,CAD module,CAM module,post- process module and CNC module),and a twin-skeg SMS as an example,the key technologies & design principle of the nodtules were investigated also Based on the above research works,the first set of 4-axis SMS Digital Manufacturing System in China has been successfully developed,which can reduce the machining time of the twin-skeg SMS from 30 working days needed for the cur- rent handcrafting manufacturing method to 8 hours now,and which can control more effectively the precision of SMS also.
文摘GS CAD98, a feature based parametric product modeling system that facilitates dexterous manipulation of mechanical design is presented. The system allows designer to make substantial changes to a part or assembly at any time during the design process. User can develop his/her own special CAD system with the help of GS CADS98s macro language PPL or kernel routines. Furthermore, it is flexible enough to exchange product data with other CAD/CAE/CAM systems according to neutral file. GS CAD98s product data is managed by an object oriented database management system called OSCAR, and the product model is built according to the standard STEP. As a result of the unified product model, all product data are globally associated in GS CAD98. GS CAD98 supports the integration with CAPP, CAM and PDM.
文摘Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequent manufacturing activities such as CAPP and CAM. A new design approach using feature technique and object oriented programming method is put forward in this paper in order to create the product information model of welding structure. With this approach, the product information model is able to effectively support computer aided welding process planning, fixturing, assembling, path planning of welding robot and other manufacturing activities. The feature classification and representing scheme of welding structure are discussed. A prototype system is developed based on feature and object oriented programming. Its structure and functions are given in detail.
基金Department of Science and Technology,Government of India for providing financial support under the scheme FIST(No.SR/FST/ETI-388/2015)。
文摘Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of geometric accuracy and surface finish, can be enhanced by using the product manufacturing information(PMI) stored in the neutral standard for the exchange of product model data(STEP) file, thereby integrating design and manufacturing. The present paper proposes a unique fixture design approach, to extract the geometry information from STEP application protocol(AP) 242 files of computer aided design(CAD) models, for providing automatic suggestions of locator positions and clamping surfaces. Automatic feature extraction software "FiXplan", developed using the programming language C#, is used to extract the part feature, dimension and geometry information. The information from the STEP AP 242 file is deduced using geometric reasoning techniques, which in turn is utilized for fixture planning. The developed software is observed to be adept in identifying the primary, secondary, and tertiary locating faces and locator position configurations of prismatic components. Structural analysis of the prismatic part under different locator positions was performed using commercial finite element method software, ABAQUS, and the optimized locator position was identified on the basis of minimum deformation of the workpiece.The area-ratio(base locator enclosed area(%)/work piece base area(%)) for the ideal locator configuration was observed as 33%. Experiments were conducted on a prismatic workpiece using a specially designed fixture, for different locator configurations. The surface roughness and waviness of the machined surfaces were analysed using an Alicona non-contact optical profilometer. The best surface characteristics were obtained for the surface machined under the ideal locator positions having an area-ratio of 33%, thus validating the predicted numerical results. The efficiency, capability and applicability of the developed software is demonstrated for the finishing operation of a sensor cover – a typical prismatic component having applications in the naval industry, under different locator configurations.The best results were obtained under the proposed ideal locator configuration of area-ratio 33%.
文摘How CAD design and simulation tools can assist in developing vacuum circuit breaker （VCB） in general is demonstrated. The electric field calculation has been widely utilized for electrical insulation design of VCB. ADAMS is applied in dynamic simulation to fulfill the complex calculation of mechanical characteristics. Satisfactory simulation results can be obtained by iteratively refining parameters of the model, and it is shown that this scheme can be used to provide a good basis for optimum design of VCB.
文摘In conformity with the principle of Design for Manufacture,feature-based design strate- (?)es have been developed.As the“feature”is relevant to the“macro process plan”and“macro NC programs”,obviously,“feature”is beyond the power of conventional solid modellers.Neverthe- less,substantial breakthrough has not been made in the solid modeling field,except“feature at- taching”or“feature recognizing”methods have been taken on.In this paper,the theory, concepts,system architecture,and algorithm principles of solid modeling tool system have been represented.The practice of Feature Solid Modeling Tool System (FSMTS) developed at Huazhong University has proved that the tool may be a new foundation of Feature-Based Design.
基金Financial support for this project was provided by the NIH F31 Grants CA12371-01 and CA12371-02the Merck-UNCF pre-doctoral fellowshipNIH grant number EB-00293.
文摘The chicken chorioallantoic membrane (CAM) is a classical in vivo biological model in studies of angiogenesis. Combined with the right tumor system and experimental configuration this classical model can offer new approaches to investigating tumor processes. The increase in development of biotechnolo- gical devices for cancer diagnosis and treatment, calls for more sophisticated tumor models that can easily adapt to the technology, and provide a more accurate, stable and consistent platform for rapid quantitative and qualitative analysis. As we discuss a variety of applications of this novel in vivo tumor spheroid based shell-less CAM model in biomedical engineering research, we will show that it is extremely versatile and easily adaptable to an array of biomedical applications. The model is particularly useful in quantitative studies of the progression of avascular tumors into vascularized tumors in the CAM. Its environment is more stable, flat and has a large working area and wider field of view excellent for imaging and longitudinal studies. Finally, rapid data acquisition, screening and validation of biomedical devices and therapeutics are possible with the short experimental window.
文摘针对金刚石滚轮是一种回转体零件以及其加工制造过程中信息化集成程度低等特点,对金刚石滚轮的特征信息提取、特征加工方案决策、数控程序后置处理等关键技术进行了研究,采用了产品模型数据交换标准STEP AP 242,实现对金刚石滚轮的制造特征信息提取,使用STEP AP 242和PDM相结合的集成方式,将金刚石滚轮三维模型作为制造加工信息的载体,并选择SolidWorks作为CAD和CAM软件,以及选择Aras Innovator作为PDM平台,使用C#编程语言和数据库技术开发了金刚石滚轮CAD/CAPP/CAM/PDM集成系统,并进行了实例验证。
