This paper describes how database information and electronic 3D models are integrated to produce power plant designs more efficiently and accurately. Engineering CAD/CAE systems have evolved from strictly 3D modeling ...This paper describes how database information and electronic 3D models are integrated to produce power plant designs more efficiently and accurately. Engineering CAD/CAE systems have evolved from strictly 3D modeling to spatial data management tools. This paper describes how process data, commodities, and location data are disseminated to the various project team members through a central integrated database. The database and 3D model also provide a cache of information that is valuable to the constructor, and operations and maintenance Personnel.展开更多
In this paper, we propose a novel AIenabled space-air-ground integrated networks(SAGIN). This new integrated networks architecture consists of LEO satellites and civil aircrafts carrying aerial base stations, called &...In this paper, we propose a novel AIenabled space-air-ground integrated networks(SAGIN). This new integrated networks architecture consists of LEO satellites and civil aircrafts carrying aerial base stations, called "civil aircraft assisted SAGIN(CAA-SAGIN)". The assistance of civil aircrafts can reduce the stress of satellite networks, improve the performance of SAGIN, decrease the construction cost and save space resources. Taking the Chinese mainland as an example, this paper has analyzed the distribution of civil aircrafts, and obtained the coverage characteristics of civil aircraft assisted networks(CAAN). Taking Starlink as the benchmark, this paper has calculated the service gap of CAAN, and designed the joint coverage constellation. The simulation results prove that the number of satellites in CAASAGIN can be greatly reduced with the assistance of civil aircrafts at the same data rate.展开更多
This paper proposes an integration mechanism to help the owners and designers to integrate sustainability issues into design process, communicate with stakeholders and achieve consensus. Literature concerning engineer...This paper proposes an integration mechanism to help the owners and designers to integrate sustainability issues into design process, communicate with stakeholders and achieve consensus. Literature concerning engineering design, decision making and environment assessment were reviewed. Sustainability disputes in construction projects were analyzed and owners and designers were interviewed to understand the evolvement of these issues. Key success factors of other successful integration projects were also referenced. An integration mechanism including procedures was established along with traditional design process. Four integration steps were developed: organize integration team, propose integration issues, determine acceptance criteria, and evaluate alternatives; and four integration dimensions were also identified: appeals, decision making and execution, stakeholders, and experts. A matrix was formed by the four integration steps and four dimensions. A rigor index was proposed to measure the quality of the integration process. Finally, the mechanism was tested on a construction project with sustainability controversy to check its validity. The study results show that the integration mechanism can help incorporate sustainability issues and achieve consensus if followed rigorously. The integration matrix systematically examines the eight key integration factors under the four dimensions. The rigor index can explain the quality in integrating sustainability issues into engineering design. The mechanism provides a useful tool for the owners and designers to cope with the sustainability decision making difficulties.展开更多
In this paper,the Web-based integration methodology and framework have been developed to facilitate collabora- tive and concurrent engineering design in distributed manufacturing environments.The distributed concurren...In this paper,the Web-based integration methodology and framework have been developed to facilitate collabora- tive and concurrent engineering design in distributed manufacturing environments.The distributed concurrent engineering and co- design are discussed as key components in the mechanism.The related integration system is presented,which includes four function- al modules:co-design,Web-based visualization,manufacturing analysis and look-up service.It can be used for a design team geo- graphically distributed to organize a collaborative and concurrent engineering design effectively.In particular,the collaborative mechanism incorporated with Java-based and Internet-enabled technologies can generate extended strategies for design and planning. Thus,the proposed integration architecture enables the system to be generic,open and scalable.Finally,for the trend of global manufacturing,a case study of Internet-enabled collaborative optimization is introduced and a discussion on teamwork capability is made.展开更多
The poppet valves two-stroke(PV2S)aircraft engine fueled with sustainable aviation fuel is a promising option for general aviation and unmanned aerial vehicle propulsion due to its high power-to-weight ratio,uniform t...The poppet valves two-stroke(PV2S)aircraft engine fueled with sustainable aviation fuel is a promising option for general aviation and unmanned aerial vehicle propulsion due to its high power-to-weight ratio,uniform torque output,and flexible valve timings.However,its high-altitude gas exchange performance remains unexplored,presenting new opportunities for optimization through artificial intelligence(AI)technology.This study uses validated 1D+3D models to evaluate the high-altitude gas exchange performance of PV2S aircraft engines.The valve timings of the PV2S engine exhibit considerable flexibility,thus the Latin hypercube design of experiments(DoE)methodology is employed to fit a response surface model.A genetic algorithm(GA)is applied to iteratively optimize valve timings for varying altitudes.The optimization process reveals that increasing the intake duration while decreasing the exhaust duration and valve overlap angles can significantly enhance high-altitude gas exchange performance.The optimal valve overlap angle emerged as 93°CA at sea level and 82°CA at 4000 m altitude.The effects of operating parameters,including engine speed,load,and exhaust back pressure,on the gas exchange process at varying altitudes are further investigated.The higher engine speed increases trapping efficiency but decreases the delivery ratio and charging efficiency at various altitudes.This effect is especially pronounced at elevated altitudes.The increase in exhaust back pressure will significantly reduce the delivery ratio and increase the trapping efficiency.This study demonstrates that integrating DoE with AI algorithms can enhance the high-altitude performance of aircraft engines,serving as a valuable reference for further optimization efforts.展开更多
In the current scenario of global competition and short product life cycles, customer-defined satisfaction has attracted interest in artifact design. Accordingly, intelligent decision-making through multi-objective op...In the current scenario of global competition and short product life cycles, customer-defined satisfaction has attracted interest in artifact design. Accordingly, intelligent decision-making through multi-objective optimization has been proposed as an efficient method for human-centered manufacturing. However, previous vast researches on optimization have been mainly focused on optimization theory and optimization techniques and paid little interests on the process of problem formulation itself. In this paper, therefore, the authors present a total framework for supporting multi-objective decision making. Then, the authors try to solve the formulated multi-objective optimization problem that involves both qualitative and quantitative performance measures as a general consequence from the above procedure. Taking especially quality as a qualitative measure, the authors gave a new idea to evaluate the quality quantitatively. Additionally, to facilitate the portability of the proposed method in multidisciplinary decision-making environments, the authors implement the proposal algorithm in an Excel spreadsheet and validate the effectiveness of the approach through a case study.展开更多
In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, i...In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today's material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH & Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.展开更多
A new method, Collaborative Allocation (CA), is proposed to solve the large-scale optimum allocation problem in aircraft conceptual design. According to the characteristics of optimum allocation in aircraft conceptu...A new method, Collaborative Allocation (CA), is proposed to solve the large-scale optimum allocation problem in aircraft conceptual design. According to the characteristics of optimum allocation in aircraft conceptual design. The principle and mathematical model of CA are established. The optimum allocation problem is decomposed into one main optimization problem and several sub-optimization problems. A group of design requirements for subsystems are provided by the main system respectively, and the subsystems execute their own optimizations or further provide the detailed design requirements to the bottom components of aircraft, such as spars, ribs and skins, etc. The subsystems minimize the discrepancy between their own local variables and the corresponding allocated values, and then return the optimization results to main optimization. The main optimization is performed to reallocate the design requirements for improving the integration performance and progressing toward the compatibilities among subsystems. CA provides the general optimum allocation architecture and is easy to be carried out. Furthermore, the concurrent computation can also be realized. Two examples of optimum reliability allocation are used to describe the implementation procedure of CA for two-level allocation and three-level allocation respectively, and to validate preliminarily its correctness and effectiveness. It is shown that the developed method can be successfully used in optimum allocation of design requirements. Then taking weight requirement allocation as example, the mathematical model and solution procedure for collaborative allocation of design requirements in aircraft conceptual design are briefly depicted.展开更多
Turbocharging technology is today considered as a promising way for internal combustion engine energy saving and CO2 reduction.Turbocharger design is a major challenge for turbocharged engine performance improvement.T...Turbocharging technology is today considered as a promising way for internal combustion engine energy saving and CO2 reduction.Turbocharger design is a major challenge for turbocharged engine performance improvement.The turbocharger designer must draw upon the information of engine operation conditions,and an appropriate link between the engine requirements and design features must be carefully developed to generate the most suitable design recommendation.The objective of this research is to develop a turbocharger design approach for better turbocharger matching to an internal combustion engine.The development of the approach is based on the concept of turbocharger design and interaction links between engine cycle requirements and design parameter values.A turbocharger through flow model is then used to generate the design alternatives.This integrated method has been applied with success to a gasoline engine turbocharger assembly.展开更多
Building owners,designers and constructors are seeing a rapid increase in the number of sustainably designed high performance buildings.These buildings provide numerous benefits to the owners and occupants to include ...Building owners,designers and constructors are seeing a rapid increase in the number of sustainably designed high performance buildings.These buildings provide numerous benefits to the owners and occupants to include improved indoor air quality,energy efficiency,and environmental site standards;and ultimately enhance productivity for the building occupants.As the demand increases for higher building energy efficiency and environmental standards,application of a set of process models will support consistency and optimization during the design process.Systems engineering process models have proven effective in taking an integrated and comprehensive view of a system while allowing for clear stakeholder engagement,requirements definition,life cycle analysis,technology insertion,validation and verification.This paper overlays systems engineering on the sustainable design process by providing a framework for application of the Waterfall,Vee,and Spiral process models to high performance buildings.Each process model is mapped to the sustainable design process and is evaluated for its applicability to projects and building types.Adaptations of the models are provided as Green Building Process Models.展开更多
文摘This paper describes how database information and electronic 3D models are integrated to produce power plant designs more efficiently and accurately. Engineering CAD/CAE systems have evolved from strictly 3D modeling to spatial data management tools. This paper describes how process data, commodities, and location data are disseminated to the various project team members through a central integrated database. The database and 3D model also provide a cache of information that is valuable to the constructor, and operations and maintenance Personnel.
基金supported by National Nature Science Foundation of China (No. 61871155)。
文摘In this paper, we propose a novel AIenabled space-air-ground integrated networks(SAGIN). This new integrated networks architecture consists of LEO satellites and civil aircrafts carrying aerial base stations, called "civil aircraft assisted SAGIN(CAA-SAGIN)". The assistance of civil aircrafts can reduce the stress of satellite networks, improve the performance of SAGIN, decrease the construction cost and save space resources. Taking the Chinese mainland as an example, this paper has analyzed the distribution of civil aircrafts, and obtained the coverage characteristics of civil aircraft assisted networks(CAAN). Taking Starlink as the benchmark, this paper has calculated the service gap of CAAN, and designed the joint coverage constellation. The simulation results prove that the number of satellites in CAASAGIN can be greatly reduced with the assistance of civil aircrafts at the same data rate.
文摘This paper proposes an integration mechanism to help the owners and designers to integrate sustainability issues into design process, communicate with stakeholders and achieve consensus. Literature concerning engineering design, decision making and environment assessment were reviewed. Sustainability disputes in construction projects were analyzed and owners and designers were interviewed to understand the evolvement of these issues. Key success factors of other successful integration projects were also referenced. An integration mechanism including procedures was established along with traditional design process. Four integration steps were developed: organize integration team, propose integration issues, determine acceptance criteria, and evaluate alternatives; and four integration dimensions were also identified: appeals, decision making and execution, stakeholders, and experts. A matrix was formed by the four integration steps and four dimensions. A rigor index was proposed to measure the quality of the integration process. Finally, the mechanism was tested on a construction project with sustainability controversy to check its validity. The study results show that the integration mechanism can help incorporate sustainability issues and achieve consensus if followed rigorously. The integration matrix systematically examines the eight key integration factors under the four dimensions. The rigor index can explain the quality in integrating sustainability issues into engineering design. The mechanism provides a useful tool for the owners and designers to cope with the sustainability decision making difficulties.
文摘In this paper,the Web-based integration methodology and framework have been developed to facilitate collabora- tive and concurrent engineering design in distributed manufacturing environments.The distributed concurrent engineering and co- design are discussed as key components in the mechanism.The related integration system is presented,which includes four function- al modules:co-design,Web-based visualization,manufacturing analysis and look-up service.It can be used for a design team geo- graphically distributed to organize a collaborative and concurrent engineering design effectively.In particular,the collaborative mechanism incorporated with Java-based and Internet-enabled technologies can generate extended strategies for design and planning. Thus,the proposed integration architecture enables the system to be generic,open and scalable.Finally,for the trend of global manufacturing,a case study of Internet-enabled collaborative optimization is introduced and a discussion on teamwork capability is made.
基金funded by the Basic Research Program of the National Natural Science Foundation of China[grant numbers 52206131,U2333217,U2233213,and 51775025]National Key R&D Program of China[grant number 2022YFB2602002 and 2018YFB0104100]+1 种基金Zhejiang Provincial Natural Science Foundation of China[grant number LQ22E060004]Science Center of Gas Turbine Project[grant number P2022-A-I-001-001].
文摘The poppet valves two-stroke(PV2S)aircraft engine fueled with sustainable aviation fuel is a promising option for general aviation and unmanned aerial vehicle propulsion due to its high power-to-weight ratio,uniform torque output,and flexible valve timings.However,its high-altitude gas exchange performance remains unexplored,presenting new opportunities for optimization through artificial intelligence(AI)technology.This study uses validated 1D+3D models to evaluate the high-altitude gas exchange performance of PV2S aircraft engines.The valve timings of the PV2S engine exhibit considerable flexibility,thus the Latin hypercube design of experiments(DoE)methodology is employed to fit a response surface model.A genetic algorithm(GA)is applied to iteratively optimize valve timings for varying altitudes.The optimization process reveals that increasing the intake duration while decreasing the exhaust duration and valve overlap angles can significantly enhance high-altitude gas exchange performance.The optimal valve overlap angle emerged as 93°CA at sea level and 82°CA at 4000 m altitude.The effects of operating parameters,including engine speed,load,and exhaust back pressure,on the gas exchange process at varying altitudes are further investigated.The higher engine speed increases trapping efficiency but decreases the delivery ratio and charging efficiency at various altitudes.This effect is especially pronounced at elevated altitudes.The increase in exhaust back pressure will significantly reduce the delivery ratio and increase the trapping efficiency.This study demonstrates that integrating DoE with AI algorithms can enhance the high-altitude performance of aircraft engines,serving as a valuable reference for further optimization efforts.
文摘In the current scenario of global competition and short product life cycles, customer-defined satisfaction has attracted interest in artifact design. Accordingly, intelligent decision-making through multi-objective optimization has been proposed as an efficient method for human-centered manufacturing. However, previous vast researches on optimization have been mainly focused on optimization theory and optimization techniques and paid little interests on the process of problem formulation itself. In this paper, therefore, the authors present a total framework for supporting multi-objective decision making. Then, the authors try to solve the formulated multi-objective optimization problem that involves both qualitative and quantitative performance measures as a general consequence from the above procedure. Taking especially quality as a qualitative measure, the authors gave a new idea to evaluate the quality quantitatively. Additionally, to facilitate the portability of the proposed method in multidisciplinary decision-making environments, the authors implement the proposal algorithm in an Excel spreadsheet and validate the effectiveness of the approach through a case study.
文摘In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today's material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH & Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.
基金National Natural Science Foundation of China (10377015)
文摘A new method, Collaborative Allocation (CA), is proposed to solve the large-scale optimum allocation problem in aircraft conceptual design. According to the characteristics of optimum allocation in aircraft conceptual design. The principle and mathematical model of CA are established. The optimum allocation problem is decomposed into one main optimization problem and several sub-optimization problems. A group of design requirements for subsystems are provided by the main system respectively, and the subsystems execute their own optimizations or further provide the detailed design requirements to the bottom components of aircraft, such as spars, ribs and skins, etc. The subsystems minimize the discrepancy between their own local variables and the corresponding allocated values, and then return the optimization results to main optimization. The main optimization is performed to reallocate the design requirements for improving the integration performance and progressing toward the compatibilities among subsystems. CA provides the general optimum allocation architecture and is easy to be carried out. Furthermore, the concurrent computation can also be realized. Two examples of optimum reliability allocation are used to describe the implementation procedure of CA for two-level allocation and three-level allocation respectively, and to validate preliminarily its correctness and effectiveness. It is shown that the developed method can be successfully used in optimum allocation of design requirements. Then taking weight requirement allocation as example, the mathematical model and solution procedure for collaborative allocation of design requirements in aircraft conceptual design are briefly depicted.
文摘Turbocharging technology is today considered as a promising way for internal combustion engine energy saving and CO2 reduction.Turbocharger design is a major challenge for turbocharged engine performance improvement.The turbocharger designer must draw upon the information of engine operation conditions,and an appropriate link between the engine requirements and design features must be carefully developed to generate the most suitable design recommendation.The objective of this research is to develop a turbocharger design approach for better turbocharger matching to an internal combustion engine.The development of the approach is based on the concept of turbocharger design and interaction links between engine cycle requirements and design parameter values.A turbocharger through flow model is then used to generate the design alternatives.This integrated method has been applied with success to a gasoline engine turbocharger assembly.
文摘Building owners,designers and constructors are seeing a rapid increase in the number of sustainably designed high performance buildings.These buildings provide numerous benefits to the owners and occupants to include improved indoor air quality,energy efficiency,and environmental site standards;and ultimately enhance productivity for the building occupants.As the demand increases for higher building energy efficiency and environmental standards,application of a set of process models will support consistency and optimization during the design process.Systems engineering process models have proven effective in taking an integrated and comprehensive view of a system while allowing for clear stakeholder engagement,requirements definition,life cycle analysis,technology insertion,validation and verification.This paper overlays systems engineering on the sustainable design process by providing a framework for application of the Waterfall,Vee,and Spiral process models to high performance buildings.Each process model is mapped to the sustainable design process and is evaluated for its applicability to projects and building types.Adaptations of the models are provided as Green Building Process Models.