The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficien...The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.展开更多
Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polariz...Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polarization.In this work,we introduce and validate a new approach for generating these beams,allowing the selection of diffferent azimuthally-variant phase gradients and vector states,thereby enabling full control over the phase and polarization patterns of perfect vortices.Using dual-functional silicon metaoptics,we achieve the compact generation of a novel class of perfect vortices,termed azimuthally-variant perfect vector beams.The optical characterization of the generated beams,performed through a filtering method,confirms their intrinsic azimuthally-variant vectorial nature.These beams exhibit unique properties that promise valuable applications in optical tweezing,the manipulation of low-refractive-index particles,the trapping of cold atoms,and high-capacity communications.展开更多
To reduce the friction of a piston ring while maintaining a large oil film load-carrying capacity,an approach comprising of the inverse method and the sequential quadratic programming algorithm was proposed.The approa...To reduce the friction of a piston ring while maintaining a large oil film load-carrying capacity,an approach comprising of the inverse method and the sequential quadratic programming algorithm was proposed.The approach considers the variation of mixed lubrication and variable lubricant viscosity with temperature along the engine stroke,is developed to optimize the profile of a piston ring.A piston ring profile is represented by a polynomial function.A case study of the second piston ring shows that the proposed method can be applied for the optimization of a piston ring profile.In addition,this paper illustrates the effects of the degree of a polynomial function.The results show that the minimization of friction and maximization of oil film load-carrying capacity can be balanced simultaneously when the degree of the polynomial is 2 and 5.展开更多
基金the National Natural Science Foundation of China(No.52275378)the National Key Laboratory for Precision Hot Processing of Metals(6142909200208)。
文摘The big-tapered profiled ring disk is a key component of engines for rockets and missiles.A new forming technology,as called spinning-rolling process,has been proposed previously for the high performance,high efficiency and low-cost manufacturing of the component.Blank design is the key part of plastic forming process design.For spinning-rolling process,the shape and size of the blank play a crucial role in process stability,deformation behavior and dimensional accuracy.So this work proposes a blank design method to determine the geometry structure and sizes of the blank.The mathematical model for calculating the blank size has been deduced based on volume conservation and neutral layer length invariance principle.The FE simulation and corresponding trial production of an actual big-tapered profiled ring disk show that the proposed blank design method is applicative.In order to obtain a preferred blank,the influence rules of blank size determined by different deformation degrees(rolling ratio k)on the spinning-rolling process are revealed by comprehensive FE simulations.Overall considering the process stability,circularity of the deformed ring disk and forming forces,a reasonable range of deformation degree(rolling ratio k)is recommended for the blank design of the new spinning-rolling process.
文摘Perfect vortices,recognized for their distinct ring profile that remains independent of the topological charge,present significant challenges in generation due to the precise control needed over both phase and polarization.In this work,we introduce and validate a new approach for generating these beams,allowing the selection of diffferent azimuthally-variant phase gradients and vector states,thereby enabling full control over the phase and polarization patterns of perfect vortices.Using dual-functional silicon metaoptics,we achieve the compact generation of a novel class of perfect vortices,termed azimuthally-variant perfect vector beams.The optical characterization of the generated beams,performed through a filtering method,confirms their intrinsic azimuthally-variant vectorial nature.These beams exhibit unique properties that promise valuable applications in optical tweezing,the manipulation of low-refractive-index particles,the trapping of cold atoms,and high-capacity communications.
基金This study is supported by the National Natural Science Foundation of China，Research Project of State Key Laboratory of Mechanical System and Vibration
文摘To reduce the friction of a piston ring while maintaining a large oil film load-carrying capacity,an approach comprising of the inverse method and the sequential quadratic programming algorithm was proposed.The approach considers the variation of mixed lubrication and variable lubricant viscosity with temperature along the engine stroke,is developed to optimize the profile of a piston ring.A piston ring profile is represented by a polynomial function.A case study of the second piston ring shows that the proposed method can be applied for the optimization of a piston ring profile.In addition,this paper illustrates the effects of the degree of a polynomial function.The results show that the minimization of friction and maximization of oil film load-carrying capacity can be balanced simultaneously when the degree of the polynomial is 2 and 5.
