The unpowered high-speed vehicle experiences a significant coupling between the disciplines of aerodynamics and control due to its characteristics of high flight speed and extensive maneuverability within large airspa...The unpowered high-speed vehicle experiences a significant coupling between the disciplines of aerodynamics and control due to its characteristics of high flight speed and extensive maneuverability within large airspace.The conventional aircraft conceptual design process follows a sequential design approach,and there is an artificial separation between the disciplines of aerodynamics and control,neglecting the coupling effects arising from their interaction.As a result,this design process often requires extensive iterations over long periods when applied to high-speed vehicles,and may not be able to effectively achieve the desired design objectives.To enhance the overall performance and design efficiency of high-speed vehicles,this study integrates the concept of Active Control Technology(ACT)from modern aircraft into the philosophy of aerodynamic/control integrated optimization.Two integrated optimization strategies,with differences in coupling granularity,have been developed.Subsequently,these strategies are put into action on a biconical vehicle that operates at Mach 5.The results reveal that the comprehensive performance of the synthesis optimal model derived from the aerodynamic/control integrated optimization strategy is improved by 31.76%and 28.29%respectively compared to the base model under high-speed conditions,demonstrating the feasibility and effectiveness of the method and optimization strategies employed.Moreover,in comparison to the single-stage strategy,the multi-stage strategy takes into deeper consideration the impact of control capacity.As a result,the control performance of the synthesis opti-mal model derived from the multi-stage strategy improves by 13.99%,whereas the single-stage strategy only achieves a 5.79%improvement.This method enables a fruitful interaction between aerodynamic configuration design and control system design,leading to enhanced overall performance and design efficiency.Furthermore,it improves the controllability of high-speed vehicles,mitigating the risk of mission failure resulting from an ineffective control system.展开更多
Presently,the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components.A high-efficiency and quality manufacturing of these complex ...Presently,the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components.A high-efficiency and quality manufacturing of these complex thin-walled components creates a bottleneck that needs to be solved urgently in machinery manufacturing.To address this problem,the collaborative manufacturing of structure shape and surface integrity has emerged as a new process that can shorten processing cycles,improve machining qualities,and reduce costs.This paper summarises the research status on the material removal mechanism,precision control of structure shape,machined surface integrity control and intelligent process control technology of complex thin-walled components.Numerous solutions and technical approaches are then put forward to solve the critical problems in the high-performance manufacturing of complex thin-wall components.The development status,challenge and tendency of collaborative manufacturing technologies in the high-efficiency and quality manufacturing of complex thin-wall components is also discussed.展开更多
Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening m...Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening model was proposed. In this model, the roll barrel was considered as a finite length semi-infinite body. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distributed force was obtained and an accurate roll flattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the first intermediate roll taper angle and taper length were analyzed. The tension distribution calculated by analytical model was consistent with the experimental results.展开更多
As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengi...As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengines.Based on SL and digital light processing(DLP),ceramic SL has technical advantages such as high flexibility,short process flow,and integrated structure-performance manufacturing,making it ideal for manufacturing complex hollow ceramic cores.Currently,ceramic cores produced using this technology still encounter several challenges such as low bending strength,low dimensional accuracy,significant sintering shrinkage,and poor surface quality,which limit the innovative development and engineering applications of the additive manufacturing of UV-cured ceramics.This paper reviews the development of additive manufacturing technology and equipment for the vat polymerization of ceramic cores used in aeroengine blades and summarizes the principles and characteristics of vat polymerization for manufacturing ceramic cores.It also highlights research progress in lightweight structural design methods for ceramic cores,ceramic slurry preparation processes,SL processes,debinding and sintering processes,integration of forming system equipment,and verification of aeroengine blade casting.A comprehensive performance control strategy for the SL of ceramic cores is proposed,and future development directions and trends in ceramic-core fabrication using SL technology are discussed.展开更多
焊后热处理是现代制造业至关重要的工艺环节。随着智能化技术的发展,人们对热处理设备的智能化要求同步提高。诸多异型件产品因形状构造复杂,局部加热均匀性和温度平稳可控性面临巨大挑战。为满足均匀加热产品的需求,读取多部位不同规...焊后热处理是现代制造业至关重要的工艺环节。随着智能化技术的发展,人们对热处理设备的智能化要求同步提高。诸多异型件产品因形状构造复杂,局部加热均匀性和温度平稳可控性面临巨大挑战。为满足均匀加热产品的需求,读取多部位不同规格加热器电阻值,分配对应电压值,进而分配所需加热功率。设备读取到各部件此刻温度,利用比例-积分-微分(Proportional Integral Derivative,PID)算法实现产品热处理中的数据采集和同步控温,使产品受热均匀且温差小。展开更多
The CuO nanocrystals were prepared by quick-precipitation and hydrolysis method respectively, using Cu(Ac)2 and NaOH as starting materials. The as-prepared CuO nanocrystals were characterized by XRD, TEM, XPS, UV-Visi...The CuO nanocrystals were prepared by quick-precipitation and hydrolysis method respectively, using Cu(Ac)2 and NaOH as starting materials. The as-prepared CuO nanocrystals were characterized by XRD, TEM, XPS, UV-Visible absorption spectroscopy and BET. The catalysis of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was investigated by thermal analysis. Results indicated the variation in temperature for NaOH addition played an important role in the shape of the CuO nanocrystals in precipitation method. Well-dispersed spherical CuO nanocrystals with an average size of 6 nm could be obtained when NaOH was added at 100 ℃ and spindle-shaped CuO nanocrystals exceeding 100 nm in diameter were obtained when NaOH was added at room temperature. Needle-shaped CuO nanocrystals could be prepared by the hydrolysis method, and the presence of small amounts of cetyltrimethylammonium bromide (CTAB) could make needle-shaped CuO well dispersed. The catalytic activity of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was high. The 2% of spherical CuO nanocrystals could make higher decomposition temperature of ammonium perchlorate decreased to 102 ℃. The exothermic quantity of decomposition was from 590 J·g-1 up to 1 420 J·g-1.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92371201,52192633)the Natural Science Foundation of Shaanxi Province(No.2022JC-03)Chinese Aeronautical Foundation(No.ASFC-20220019070002)。
文摘The unpowered high-speed vehicle experiences a significant coupling between the disciplines of aerodynamics and control due to its characteristics of high flight speed and extensive maneuverability within large airspace.The conventional aircraft conceptual design process follows a sequential design approach,and there is an artificial separation between the disciplines of aerodynamics and control,neglecting the coupling effects arising from their interaction.As a result,this design process often requires extensive iterations over long periods when applied to high-speed vehicles,and may not be able to effectively achieve the desired design objectives.To enhance the overall performance and design efficiency of high-speed vehicles,this study integrates the concept of Active Control Technology(ACT)from modern aircraft into the philosophy of aerodynamic/control integrated optimization.Two integrated optimization strategies,with differences in coupling granularity,have been developed.Subsequently,these strategies are put into action on a biconical vehicle that operates at Mach 5.The results reveal that the comprehensive performance of the synthesis optimal model derived from the aerodynamic/control integrated optimization strategy is improved by 31.76%and 28.29%respectively compared to the base model under high-speed conditions,demonstrating the feasibility and effectiveness of the method and optimization strategies employed.Moreover,in comparison to the single-stage strategy,the multi-stage strategy takes into deeper consideration the impact of control capacity.As a result,the control performance of the synthesis opti-mal model derived from the multi-stage strategy improves by 13.99%,whereas the single-stage strategy only achieves a 5.79%improvement.This method enables a fruitful interaction between aerodynamic configuration design and control system design,leading to enhanced overall performance and design efficiency.Furthermore,it improves the controllability of high-speed vehicles,mitigating the risk of mission failure resulting from an ineffective control system.
基金supported by the National Natural Science Foundation of China(Nos.51921003,92160301,52175415 and 52205475)the Science Center for Gas Turbine Project(No.P2022-A-IV-002-001)Natural Science Foundation of Jiangsu Province(No.BK20210295).
文摘Presently,the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components.A high-efficiency and quality manufacturing of these complex thin-walled components creates a bottleneck that needs to be solved urgently in machinery manufacturing.To address this problem,the collaborative manufacturing of structure shape and surface integrity has emerged as a new process that can shorten processing cycles,improve machining qualities,and reduce costs.This paper summarises the research status on the material removal mechanism,precision control of structure shape,machined surface integrity control and intelligent process control technology of complex thin-walled components.Numerous solutions and technical approaches are then put forward to solve the critical problems in the high-performance manufacturing of complex thin-wall components.The development status,challenge and tendency of collaborative manufacturing technologies in the high-efficiency and quality manufacturing of complex thin-wall components is also discussed.
基金Item Sponsored by National Natural Science Foundation of China(51474190)Natural Sceince Foundation of Hebei Province of China(E2015203311)
文摘Roll flattening theory is an important part of plate shape control theories for 20-high mill. In order to improve the accuracy of roll flattening calculation for 20-high mill, a new and more accurate roll flattening model was proposed. In this model, the roll barrel was considered as a finite length semi-infinite body. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distributed force was obtained and an accurate roll flattening model was established. Coupled with roll bending model and strip plastic deformation, a new and more accurate plate control model for 20-high mill was established. Moreover, the effects of the first intermediate roll taper angle and taper length were analyzed. The tension distribution calculated by analytical model was consistent with the experimental results.
基金supported by Jiangsu Provincial Basic Research Program(Natural Science Foundation)Youth Fund(Grant No.BK20230885)International Joint Laboratory of Sustainable Manufacturing,Ministry of Education,Fundamental Research Funds for Central Universities(Grant No.NG2024012)+1 种基金Basic Research Project for Major Special Programs of Aero-Engine and Gas Turbine(Grant No.J2022-Ⅶ-0006-0048)High-Quality Development Special Project of the Ministry of Industry and Information Technology.
文摘As a key process in the manufacturing of hollow turbine blades for aeroengines,ceramic-core stereolithography(SL)is vital for the structural design and precise performance control of hollow turbine blades for aeroengines.Based on SL and digital light processing(DLP),ceramic SL has technical advantages such as high flexibility,short process flow,and integrated structure-performance manufacturing,making it ideal for manufacturing complex hollow ceramic cores.Currently,ceramic cores produced using this technology still encounter several challenges such as low bending strength,low dimensional accuracy,significant sintering shrinkage,and poor surface quality,which limit the innovative development and engineering applications of the additive manufacturing of UV-cured ceramics.This paper reviews the development of additive manufacturing technology and equipment for the vat polymerization of ceramic cores used in aeroengine blades and summarizes the principles and characteristics of vat polymerization for manufacturing ceramic cores.It also highlights research progress in lightweight structural design methods for ceramic cores,ceramic slurry preparation processes,SL processes,debinding and sintering processes,integration of forming system equipment,and verification of aeroengine blade casting.A comprehensive performance control strategy for the SL of ceramic cores is proposed,and future development directions and trends in ceramic-core fabrication using SL technology are discussed.
文摘焊后热处理是现代制造业至关重要的工艺环节。随着智能化技术的发展,人们对热处理设备的智能化要求同步提高。诸多异型件产品因形状构造复杂,局部加热均匀性和温度平稳可控性面临巨大挑战。为满足均匀加热产品的需求,读取多部位不同规格加热器电阻值,分配对应电压值,进而分配所需加热功率。设备读取到各部件此刻温度,利用比例-积分-微分(Proportional Integral Derivative,PID)算法实现产品热处理中的数据采集和同步控温,使产品受热均匀且温差小。
文摘The CuO nanocrystals were prepared by quick-precipitation and hydrolysis method respectively, using Cu(Ac)2 and NaOH as starting materials. The as-prepared CuO nanocrystals were characterized by XRD, TEM, XPS, UV-Visible absorption spectroscopy and BET. The catalysis of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was investigated by thermal analysis. Results indicated the variation in temperature for NaOH addition played an important role in the shape of the CuO nanocrystals in precipitation method. Well-dispersed spherical CuO nanocrystals with an average size of 6 nm could be obtained when NaOH was added at 100 ℃ and spindle-shaped CuO nanocrystals exceeding 100 nm in diameter were obtained when NaOH was added at room temperature. Needle-shaped CuO nanocrystals could be prepared by the hydrolysis method, and the presence of small amounts of cetyltrimethylammonium bromide (CTAB) could make needle-shaped CuO well dispersed. The catalytic activity of CuO nanocrystals of different morphologies on ammonium perchlorate decomposition was high. The 2% of spherical CuO nanocrystals could make higher decomposition temperature of ammonium perchlorate decreased to 102 ℃. The exothermic quantity of decomposition was from 590 J·g-1 up to 1 420 J·g-1.
