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Elliptical vibration cutting of large-size thin-walled curved surface parts of pure iron by using diamond tool with active cutting edge shift

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Chinese Journal of Aeronautics 2023年第6期36卷 402-419页

作者： Zhenhua JIAO Renke KANG Dongxing DU Jiang GUO Key Laboratory for Precision and Non-traditional Machining of Ministry of Education Dalian University of TechnologyDalian 116024China Institute of Mechanical Manufacturing Technology China Academy of Engineering PhysicsMianyang 621999China

Large-size thin-walled curved surface parts of pure iron are crucial in aerospace,national defense,energy and precision physical experiments.However,the high machining accuracy and surface quality are difficult to achieve due to the serious tool wear and deformation when machining the parts with conventional cutting tools.In this paper,an elliptical vibration cutting(EVC)with active cutting edge shift(ACES)based on a long arbor vibration device is proposed for ultraprecision machining the pure iron parts by using diamond tool.Compared with cutting at a fixed cutting edge,the influence of ACES on the EVC was analyzed.Experiments in EVC of pure iron with ACES were conducted.The evolutions of the surface roughness,surface topography,and chip morphology with tool wear in EVC with ACES are revealed.The reasonable parameters of ultraprecision machining the pure iron parts by EVC with ACES were determined.It shows that the ACES has a slight influence on the machined surface roughness and surface topography.The diamond tool life can be significantly prolonged in EVC of pure iron with ACES than that with a fixed cutting edge,so that high profile accuracy and surface quality could be obtained even at higher nominal cutting speed.A typical thin-walled curved surface pure iron part with diameter φ240 mm,height 122 mm,and wall thickness 2 mm was fabricated by the presented method,and its profile error and surface roughness achieved PV 2.2μm and Ra less than 50 nm,respectively.

关键词： curved surface Diamond tool Elliptical vibration cutting Pure iron Thin-walled parts

A New Dynamics Analysis Model for Five-Axis Machining of curved surface Based on Dimension Reduction and Mapping

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 172-184页

作者： Minglong Guo Zhaocheng Wei Minjie Wang Zhiwei Zhao Shengxian Liu Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024People’s Republic of China Institute of Mechanical Manufacturing Technology China Academy of Engineering PhysicsMianyang 621000China

The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing size.Five-axis computer numerical control(CNC)milling is the main parts machining method,while dynamics analysis has always been a research hotspot.The cutting conditions determined by the cutter axis,tool path,and workpiece geometry are complex and changeable,which has made dynamics research a major challenge.For this reason,this paper introduces the innovative idea of applying dimension reduction and mapping to the five-axis machining of curved surfaces,and proposes an efficient dynamics analysis model.To simplify the research object,the cutter position points along the tool path were discretized into inclined plane five-axis machining.The cutter dip angle and feed deflection angle were used to define the spatial position relationship in five-axis machining.These were then taken as the new base variables to construct an abstract two-dimensional space and establish the mapping relationship between the cutter position point and space point sets to further simplify the dimensions of the research object.Based on the in-cut cutting edge solved by the space limitation method,the dynamics of the inclined plane five-axis machining unit were studied,and the results were uniformly stored in the abstract space to produce a database.Finally,the prediction of the milling force and vibration state along the tool path became a data extraction process that significantly improved efficiency.Two experiments were also conducted which proved the accuracy and efficiency of the proposed dynamics analysis model.This study has great potential for the online synchronization of intelligent machining of large surfaces.

关键词： curved surface Five-axis machining Dimension reduction and mapping Milling force Dynamics

Unsteady Flow and Heat Transfer of a Casson Micropolar Nanofluid over a curved Stretching/Shrinking surface

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Fluid Dynamics & Materials Processing 2023年第2期19卷 471-486页

作者： Muhammad A.Sadiq Nadeem Abbas Haitham M.S.Bahaidarah Mohammad Amjad Department of Mathematics DCC-KFUPMDhahran31261Saudi Arabia Interdisciplinary Research Center for Hydrogen and Energy Storage KFUPMDhahran31261Saudi Arabia Department of Mathematics Riphah International UniversityFaisalabad CampusFaisalabad38000Pakistan Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Department of Mathematics AIR UniversityIslamabad44000Pakistan

We present the results of an investigation into the behavior of the unsteady flow of a Casson Micropolar nanofluid over a shrinking/stretching curved surface,together with a heat transfer analysis of the same problem.The body force acting perpendicular to the surface wall is in charge of regulating the fluid flow rate.Curvilinear coordinates are used to account for the considered curved geometry and a set of balance equations for mass,momentum,energy and concentration is obtained accordingly.These are turned into ordinary differential equations using a similarity transformation.We show that these equations have dual solutions for a number of different combinations of various parameters.The stability of such solutions is investigated by applying perturbations on the steady states.It is found that high values of the Micropolar and Casson parameters cause the flow to move more slowly.However,when compared to a shrunken surface,a stretched surface produces a greater Micro-rotation flux.

关键词： Dual solutions Micropolar Casson fluid curved surface perturbation eigen values

Artificial neural network model of non-Darcy MHD Sutterby hybrid nanofluid flow over a curved permeable surface:Solar energy applications

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Propulsion and Power Research 2023年第3期12卷 410-427页

作者： Shaik Jakeer Maduru Lakshmi Rupa Seethi Reddy Reddisekhar Reddy A.M.Rashad Centre for Computational Modeling Chennai Institute of TechnologyChennai 600069India Department of Mathematics S.A.S.Vellore Institute of TechnologyVellore 632014India Department of Mathematics Koneru Lakshmaiah Education FoundationBowrampetHyderabad 500043TelanganaIndia Department of Mathematics Aswan UniversityFaculty of ScienceAswan 81528Egypt

The conversion of solar radiation to thermal energy has recently much interest as the requirement for renewable heat and power grows.Due to their enhanced ability to promote heat transmission,nanofluids can significantly improve solar-thermal systems’efficiency.This section aims to study the heat transfer behavior of the Sutterby hybrid nanofluid flow of magnetohydrodynamics in the presence of a non-uniform heat source/sink and linear thermal radiation over a non-Darcy curved permeable surface.A novel implementation of an intelligent numerical computing solver based on multi-layer perceptron(MLP)feed-forward back-propagation artificial neural network(ANN)with the Levenberg-Marquard algorithm is provided in the current study.Data were gathered for the ANN model’s testing,certification,and training.Established mathematical equations are nonlinear,which are resolved for velocity,the temperature in addition to the skin friction coefficient,and the rate of heat transfer by using the bvp4c with MATLAB solver.The ANN model selects data,constructs and trains a network,then evaluates its efficacy via mean square error.Graphs illustrate the impact of a wide range of physical factors on variables,including pressure,velocity,and temperature.In the entire study,the thermal energy improved by the SiO2(silicon dioxide)-Au(gold)hybrid nanofluid than the SiO2-TiO2(titanium dioxide)hybrid nanofluid.The higher internal heat generation/absorption parameter values increase the temperature.

关键词： ANN model Sutterby hybrid nanofluid Magnetic field Non-DarcyForchheimer curved surface Radiation

Numerical prediction of spatio-temporal frosting patterns of curved surface considering varying working parameters

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Energy Storage and Saving 2023年第1期2卷 348-358页

作者： Xue Liu Xiaojun Dong Shaohang Yan Yu Hou Tianwei Lai State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China

Accurate numerical prediction of frosting patterns is essential for the efficient layout and timing defrosting of heat exchangers under frosting conditions.In this study,a numerical model is developed to predict the spatio-temporal frosting habits on curved surfaces in combination with the correlations of frost density and thermal conductivity.In the model,frost melting is considered.After verification,the frosting and heat transfer characteristics along the flow path are investigated under various structural and operating conditions.Frost thickness along the path is mainly affected by the cooling surface temperature,while the heat and mass transfer rates are strongly correlated with the humidity ratio.The proportions of latent heat and sensible heat are distributed more unevenly in parallel flow case than in counter flow case.Frost deposition is facilitated by a smaller radius of curvature of the cooling surface.More uniform frosting characteristics along the path and smaller heat transfer obstruction are presented with a smaller length-to-height ratio of the flow path.

关键词： Frosting Numerical prediction Heat transfer curved surface Varying parameter

Effective dynamics for a spin-1/2 particle constrained to a curved layer with inhomogeneous thickness

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Chinese Physics B 2024年第2期33卷 78-83页

作者：梁国华尹佩林 School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China

We derive an effective Hamiltonian for a spin-1/2 particle confined within a curved thin layer with non-uniform thickness using the confining potential approach.Our analysis reveals the presence of a pseudo-magnetic field and effective spin–orbit interaction(SOI)arising from the curvature,as well as an effective scalar potential resulting from variations in thickness.Importantly,we demonstrate that the physical effect of additional SOI from thickness fluctuations vanishes in low-dimensional systems,thus guaranteeing the robustness of spin interference measurements to thickness imperfection.Furthermore,we establish the applicability of the effective Hamiltonian in both symmetric and asymmetric confinement scenarios,which is crucial for its utilization in one-side etching systems.

关键词： curved surface inhomogeneous thickness spin-1/2 particle effective Hamiltonian

Application of curved surface of Ball Movement in Hydraulic Engineering

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Computer Aided Drafting,Design and Manufacturing 2005年第1期15卷 16-19页

作者： PENGZheng-hong MIXin-wu SchoolofUrbanStudies WuhanUniversityWuhan430072China

The curved surface of ball movement is a connecting bent pipe commonly used in hydraulic engineering. The curved surface poses a complicated problem with computation. The mathematic model of the circular curved surfac... 详细信息

关键词： curved surface ball movement variable radius bent pipe mathematic model

High-Order Method with Moving Frames to Compute the Covariant Derivatives of Vectors on General 2D curved surfaces

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Communications on Applied Mathematics and Computation 2023年第4期5卷 1534-1563页

作者： Sehun Chun Underwood International College Yonsei UniversitySeoulSouth Korea

The covariant derivative is a generalization of differentiating vectors.The Euclidean derivative is a special case of the covariant derivative in Euclidean space.The covariant derivative gathers broad attention,particularly when computing vector derivatives on curved surfaces and volumes in various applications.Covariant derivatives have been computed using the metric tensor from the analytically known curved axes.However,deriving the global axis for the domain has been mathematically and computationally challenging for an arbitrary two-dimensional(2D)surface.Consequently,computing the covariant derivative has been difficult or even impossible.A novel high-order numerical scheme is proposed for computing the covariant derivative on any 2D curved surface.A set of orthonormal vectors,known as moving frames,expand vectors to compute accurately covariant derivatives on 2D curved surfaces.The proposed scheme does not require the construction of curved axes for the metric tensor or the Christoffel symbols.The connectivity given by the Christoffel symbols is equivalently provided by the attitude matrix of orthonormal moving frames.Consequently,the proposed scheme can be extended to the general 2D curved surface.As an application,the Helmholtz‐Hodge decomposition is considered for a realistic atrium and a bunny.

关键词： Covariant derivative Moving frames curved surface Helmholtz‐Hodge decomposition

Fluxless bonding with silver nanowires aerogel in die-attached interconnection

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China Welding 2023年第2期32卷 32-41页

作者：傅必成方毅张乐李道会齐放宋利军祝温泊 Sauvage Laboratory for Smart Materials School of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China China Academy of Space Technology Xi′an 710100China NIO Nanjing 210046China

The electronic product has gravitated towards component miniaturization and integration, employment of lead-free materials, and low-temperature soldering processes. Noble-metal aerogels have drawn increasing attention for high conduction and low density. However,the noble metal aerogels with outstanding solderability were rarely studied. This work has successfully synthesized an aerogel derived from silver nanowires(AgNWs) using a liquid phase reduction method. It is found that the noble metal aerogels can be made into diverse aerogel preformed soldering sheets. The influence of bonding temperature(150-300 ℃), time(2-20 min), and pressure(5-20 MPa) on the joint strength of the AgNWs aerogel affixed to electroless nickel/silver copper plates were investigated. Additionally, the AgNWs aerogel displays almost the same shear strength for substrates of various sizes. In a word, this study presents a flux-free, high-strength, and adaptable soldering structural material.

关键词： silver nanowires aerogel nanostructured materials soldering preform bonding curved surface