摘要：Heat-assisted rotary draw bending(HRDB)is a promising technique for manufacturing difficult-to-form tubular components comprising high-strength titanium tubes(HSTTs)with small bending ***,as a multidie constrained and thermomechanical coupled process with many uncertainty factors,a high risk of several defects,such as cross-section distortion,over wall thinning,or even cracking,is *** the robust design optimization(RDO)of complex forming processes remains a nontrivial and challenging scientific ***,considering a high-strength Ti-3Al-2.5V titanium alloy tube as a case material,the five significant uncertainty factors in HRDB,i.e.,temperature distribution,tube geometrical characteristics,tube material parameters,tube/tool friction,and boost velocity had been ***,considering the preheating and HRDB of HSTT,a whole-process thermomechanical three-dimensional finite element model was established and validated for virtual ***,considering the maximum section distortion Q and maximum wall-thickness thinning t as the optimization objectives and the mean and variance of material and forming parameters,an RDO model was ***,the Pareto optimal solutions were obtained using the nondominated sorting genetic algorithm II,and a minimum distance selection method was employed to obtain the satisfactory *** show that the optimized solutions considering the uncertainty factors reduce the maximum section distortion rate of HSTT after bending by 38.1%and the maximum wallthickness thinning rate by 27.8%.

摘要：This paper introduces the Chinese"Dove"——A practical application system of bird-mimetic air vehicles developed for more than a decade by the institute of Flight Vehicle Innovation of Northwest Polytechnic University(NWPU)in ***,the main components,flight capability and flight verification of the Chinese"Dove"are ***,the methods for the aerodynamic simulation and wind tunnel experiments are put ***,the design of high-lift and high-thrust flexible flapping wings,a series of flapping mechanisms,gust-resistance layout and micro flight control/navigation system are *** future studies on the application system of bionic micro air vehicles are given,including observation of natural flight creatures,aerodynamics in flight,mechanical and new material driving systems,structural mechanics,flight mechanics,and the information perception and intelligent decision-making control,which are related to research of flight bioinformatic perception and brain ***,some application examples of complex flapping movements,active/passive deformation of bird wings,new low-energy motion-driven system,bionic intelligent decision-making and control/navigation are discussed.

摘要：金属材料经常暴露在高应变率和复杂的应力条件下.研究这些材料的动态力学行为对工程设计和工业应用至关重要.本文研究了TC17钛合金在压缩/拉伸-扭转作用下的动态塑性流动行为.研究了TC17钛合金在准静态和动态载荷下的初始屈服行为,并采用杨、郭和李提出的动态不对称屈服准则(DAYC)来表征动态初始屈服行为.根据不同应力状态下的硬化特性,提出了一种修正的动态硬化规律(MDHL)来拟合加载面.研究了TC17钛合金在准静态和动态载荷作用下的塑性流动方向.结果表明,塑性势函数基本符合相关联流动法则.总之,本文系统性的研究了TC17钛合金的屈服性能,应变硬化规律和塑性流动规律,并利用DAYC和MDHL对其进行了表征.

摘要：The Chinese economy is currently undergoing a digital *** growth drivers are replacing old ones,creating a new development *** with strong digital industries will be the first to reap the benefits of *** China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual *** out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized *** capital,industries and technology clusters emerge as new drivers of manufacturing and service sector *** its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.