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Machinability of damage-tolerant titanium alloy in orthogonal turn-milling

Tao SUN, Lufang QIN, Junming HOU, Yucan FU

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 504-515 doi: 10.1007/s11465-020-0586-2

摘要： The damage-tolerant titanium alloy TC21 is used extensively in important parts of advanced aircraft because of its high strength and durability. However, cutting TC21 entails problems, such as high cutting temperature, high tool tip stress, rapid tool wear, and difficulty guaranteeing processing quality. Orthogonal turn-milling can be used to solve these problems. In this study, the machinability of TC21 in orthogonal turn-milling is investigated experimentally to optimize the cutting parameters of orthogonal turn-milling and improve the machining efficiency, tool life, and machining quality of TC21. The mechanism of the effect of turn-milling parameters on tool life is discussed, the relationship between each parameter and tool life is analyzed, and the failure process of a TiAlN-coated tool in turn-milling is explored. Experiments are conducted on the integrity of the machined surface (surface roughness, metallographic structure, and work hardening) by turn-milling, and how the parameters influence such integrity is analyzed. Then, reasonable cutting parameters for TC21 in orthogonal turn-milling are recommended. This study provides strong guidance for exploring the machinability of difficult-to-cut-materials in orthogonal turn-milling and improves the applicability of orthogonal turn-milling for such materials.

关键词： orthogonal turn-milling     damage-tolerant titanium alloy     tool life and failure     machined surface integrity     machinability    

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Variable eccentric distance-based tool path generation for orthogonal turn-milling

Fangyu PENG,Wei WANG,Rong YAN,Xianyin DUAN,Bin LI

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 352-366 doi: 10.1007/s11465-015-0361-y

摘要：

This study proposes an algorithm for maximizing strip width in orthogonal turn-milling based on variable eccentric distance. The machining error model is first established based on the local cutting profile at the contact line. The influencing factors of the strip width are then investigated to analyze their features and determine an optimizing strategy. The optimized model for maximum machining strip width is formulated by adopting a variable eccentric distance. Hausdorff distance and Fréchet distance are introduced in this study to implement the constraint function of the machining error in the optimized model. The computing procedure is subsequently provided. Simulations and experiments have been conducted to verify the effectiveness of the proposed algorithm.

关键词： orthogonal turn-milling     variable eccentric distance     local cutting profile     machining strip-width maximization    

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Investigating the role of exiting vehicles and turn indicator usage in gap acceptance at single-lane

Nathan P. BELZ

《结构与土木工程前沿（英文）》 2017年 第11卷 第1期   页码 8-16 doi: 10.1007/s11709-016-0365-7

摘要： Roundabouts are becoming a preferred form of intersection control type due to their safety and capacity benefits. Yield control at roundabout entries inherently reduces fuel consumption and emissions when compared to other conventional intersection types. However, these benefits can be limited by poor driver behavior and judgment when entering the roundabout. This research addresses the nature of gap distributions and use of turn indicators by exiting vehicles at three single-lane roundabouts in Vermont, New York, and Alaska. Presented here is a comparison of vehicle headways measured at two different locations in each roundabout. Rejected headways are analyzed in the context of priority abstaining events when entering drivers yield to vehicles exiting on the same leg of the roundabout suggesting that “true” critical gaps are being overestimated. Results indicate that exiting vehicles, particularly those that do not use their turn indicators when departing from the major-stream of traffic have an influence on the entry decision of drivers on the same approach. This behavior is of particular concern for intersection efficiency (i.e., delay) and sustainability (i.e., excess fuel consumption and emissions). Results prompt the consideration of more consistent guidance on and enforcement of turn indicator use during roundabout negotiations.

关键词： roundabouts     exiting vehicles     turn indicator use     headways    

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Experimental investigation and comparative study of inter-turn short-circuits and unbalanced voltage

Fatima BABAA, Abdelmalek KHEZZAR, Mohamed el kamel OUMAAMAR

《能源前沿（英文）》 2013年 第7卷 第3期   页码 271-278 doi: 10.1007/s11708-013-0258-6

摘要： A transient model for an induction machine with stator winding turn faults on a single phase is derived using reference frame transformation theory. The negative sequence component and the 3rd harmonic are often considered as accurate indicators. However, small unbalance in the supply voltage and/or in the machine structure that exists in any real system engenders the same harmonics components. In this case, it is too difficult to distinguish between the current harmonics due to the supply voltage and those originated by inter-turn short-circuit faults. For that, to have the correct diagnosis and to increase the sensitivity and the reliability of the diagnostic system, it is crucial to provide the relationship between the inter-turn short-circuits in the stator winding and the supply voltage imbalance through an accurate mathematical model and via a series of experimental essays.

关键词： induction machines     fault indicator     inter-turn short-circuit fault     unbalance supply voltage    

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Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0744-9

摘要： Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词： difficult-to-machine metal material     green machining     high-speed dry milling     laser energy field-assisted milling     ultrasonic energy field-assisted milling     cryogenic minimum quantity lubrication energy field-assisted milling    

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A novel flavonol-based colorimetric and turn-on fluorescent probe for rapid determination of hydrazine

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 24-33 doi: 10.1007/s11705-022-2171-1

摘要： Hydrazine is extremely toxic and causes severe harm to human body. Herein, a novel fluorescent probe 4-oxo-2-styryl-4H-chromen-3-yl thiophene-2-carboxylate (FHT) was synthesized for detecting hydrazine by using natural cinnamaldehyde as starting material. This probe exhibited significantly enhanced fluorescence response towards hydrazine over various common metal ions, anions, and amine compounds. The detection limit of probe FHT for hydrazine was as low as 0.14 μmol·L–1, significantly lower than that of the threshold value of 0.312 μmol·L–1, imposed by the Environmental Protection Agency. Moreover, the proposed probe was able to detect hydrazine within wide pH (5–10) and linear detection ranges (0–110 μmol·L–1). This probe was employed for determining trace hydrazine in different environmental water samples. The probe FHT-loaded filter paper strips were able to conveniently detect hydrazine of low concentration through distinct naked-eye and fluorescent color changes. Importantly, the probe FHT with low cytotoxicity was successfully applied to visualize hydrazine in living Hela cells and zebrafish.

关键词： cinnamaldehyde     3-hydroxychromone derivative     hydrazine     fluorescent probe    

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Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0680-8

摘要： Fiber-reinforced composites have become the preferred material in the fields of aviation and aerospace because of their high-strength performance in unit weight. The composite components are manufactured by near net-shape and only require finishing operations to achieve final dimensional and assembly tolerances. Milling and grinding arise as the preferred choices because of their precision processing. Nevertheless, given their laminated, anisotropic, and heterogeneous nature, these materials are considered difficult-to-machine. As undesirable results and challenging breakthroughs, the surface damage and integrity of these materials is a research hotspot with important engineering significance. This review summarizes an up-to-date progress of the damage formation mechanisms and suppression strategies in milling and grinding for the fiber-reinforced composites reported in the literature. First, the formation mechanisms of milling damage, including delamination, burr, and tear, are analyzed. Second, the grinding mechanisms, covering material removal mechanism, thermal mechanical behavior, surface integrity, and damage, are discussed. Third, suppression strategies are reviewed systematically from the aspects of advanced cutting tools and technologies, including ultrasonic vibration-assisted machining, cryogenic cooling, minimum quantity lubrication (MQL), and tool optimization design. Ultrasonic vibration shows the greatest advantage of restraining machining force, which can be reduced by approximately 60% compared with conventional machining. Cryogenic cooling is the most effective method to reduce temperature with a maximum reduction of approximately 60%. MQL shows its advantages in terms of reducing friction coefficient, force, temperature, and tool wear. Finally, research gaps and future exploration directions are prospected, giving researchers opportunity to deepen specific aspects and explore new area for achieving high precision surface machining of fiber-reinforced composites.

关键词： milling     grinding     fiber-reinforced composites     damage formation mechanism     delamination     material removal mechanism     surface integrity     minimum quantity lubrication    

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Cutting Force Model for a Small-diameter Helical Milling Cutter

LI Xiwen, YANG Shuzi, YANG Mingjin, XIE Shouyong

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 272-277 doi: 10.1007/s11465-007-0047-1

摘要： In the milling process, the major flank wear land area (two-dimensional measurement for the wear) of a small-diameter milling cutter, as wear standard, can reflect actual changes of the wear land of the cutter. By analyzing the wearing characteristics of the cutter, a cutting force model based on the major flank wear land area is established. Characteristic parameters such as pressure parameter and friction parameter are calculated by substituting tested data into their corresponding equations. The cutting force model for the helical milling cutter is validated by experiments. The computational and experimental results show that the cutting force model is almost consistent with the actual cutting conditions. Thus, the cutting force model established in the research can provide a theoretical foundation for monitoring the condition of a milling process that uses a small-diameter helical milling cutter.

关键词： computational     corresponding     helical milling     theoretical foundation     Characteristic    

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Position-varying surface roughness prediction method considering compensated acceleration in milling

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 855-867 doi: 10.1007/s11465-021-0649-z

摘要： Machined surface roughness will affect parts’ service performance. Thus, predicting it in the machining is important to avoid rejects. Surface roughness will be affected by system position dependent vibration even under constant parameter with certain toolpath processing in the finishing. Aiming at surface roughness prediction in the machining process, this paper proposes a position-varying surface roughness prediction method based on compensated acceleration by using regression analysis. To reduce the stochastic error of measuring the machined surface profile height, the surface area is repeatedly measured three times, and Pauta criterion is adopted to eliminate abnormal points. The actual vibration state at any processing position is obtained through the single-point monitoring acceleration compensation model. Seven acceleration features are extracted, and valley, which has the highest R-square proving the effectiveness of the filtering features, is selected as the input of the prediction model by mutual information coefficients. Finally, by comparing the measured and predicted surface roughness curves, they have the same trends, with the average error of 16.28% and the minimum error of 0.16%. Moreover, the prediction curve matches and agrees well with the actual surface state, which verifies the accuracy and reliability of the model.

关键词： surface roughness prediction     compensated acceleration     milling     thin-walled workpiece    

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Improved analytical model for residual stress prediction in orthogonal cutting

null

《机械工程前沿（英文）》 2014年 第9卷 第3期   页码 249-256 doi: 10.1007/s11465-014-0310-1

摘要：

The analytical model of residual stress in orthogonal cutting proposed by Jiann is an important tool for residual stress prediction in orthogonal cutting. In application of the model, a problem of low precision of the surface residual stress prediction is found. By theoretical analysis, several shortages of Jiann’s model are picked out, including: inappropriate boundary conditions, unreasonable calculation method of thermal stress, ignorance of stress constraint and cyclic loading algorithm. These shortages may directly lead to the low precision of the surface residual stress prediction. To eliminate these shortages and make the prediction more accurate, an improved model is proposed. In this model, a new contact boundary condition between tool and workpiece is used to make it in accord with the real cutting process; an improved calculation method of thermal stress is adopted; a stress constraint is added according to the volume-constancy of plastic deformation; and the accumulative effect of the stresses during cyclic loading is considered. At last, an experiment for measuring residual stress in cutting AISI 1045 steel is conducted. Also, Jiann’s model and the improved model are simulated under the same conditions with cutting experiment. The comparisons show that the surface residual stresses predicted by the improved model is closer to the experimental results than the results predicted by Jiann’s model.

关键词： residual stress     analytical model     orthogonal cutting     cutting force     cutting temperature    

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Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

《机械工程前沿（英文）》 2009年 第4卷 第4期   页码 379-385 doi: 10.1007/s11465-009-0075-0

摘要： Singularity analysis plays an important role in the design of robots, especially for parallel robots. In this paper, the direct and inverse kinematics of an orthogonal spherical two-degree-of-freedom parallel mechanism is proposed based on the modified Euler angles. All the singular poses of the mechanism are achieved through the direct kinematic analysis. Self-motions, which are different from the general spherical 5 parallel mechanisms, are also discussed. Singularity loci in the joint space and Cartesian space are plotted according to the Jacobin of the mechanism. Result shows that the singularity loci at the joint space are two circles and one line, whereas at the Cartesian space are a circle.

关键词： 2-DOF orthogonal spherical parallel mechanism     singularity loci     self-motions    

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Mechanical behavior and semiempirical force model of aerospace aluminum alloy milling using nano biological

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0720-4

摘要： Aerospace aluminum alloy is the most used structural material for rockets, aircraft, spacecraft, and space stations. The deterioration of surface integrity of dry machining and the insufficient heat transfer capacity of minimal quantity lubrication have become the bottleneck of lubrication and heat dissipation of aerospace aluminum alloy. However, the excellent thermal conductivity and tribological properties of nanofluids are expected to fill this gap. The traditional milling force models are mainly based on empirical models and finite element simulations, which are insufficient to guide industrial manufacturing. In this study, the milling force of the integral end milling cutter is deduced by force analysis of the milling cutter element and numerical simulation. The instantaneous milling force model of the integral end milling cutter is established under the condition of dry and nanofluid minimal quantity lubrication (NMQL) based on the dual mechanism of the shear effect on the rake face of the milling cutter and the plow cutting effect on the flank surface. A single factor experiment is designed to introduce NMQL and the milling feed factor into the instantaneous milling force coefficient. The average absolute errors in the prediction of milling forces for the NMQL are 13.3%, 2.3%, and 7.6% in the x-, y-, and z-direction, respectively. Compared with the milling forces obtained by dry milling, those by NMQL decrease by 21.4%, 17.7%, and 18.5% in the x-, y-, and z-direction, respectively.

关键词： milling     force     nanofluid minimum quantity lubrication     aerospace aluminum alloy     nano biological lubricant    

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A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0688-0

摘要： The use of artificial intelligence to process sensor data and predict the dimensional accuracy of machined parts is of great interest to the manufacturing community and can facilitate the intelligent production of many key engineering components. In this study, we develop a predictive model of the dimensional accuracy for precision milling of thin-walled structural components. The aim is to classify three typical features of a structural component—squares, slots, and holes—into various categories based on their dimensional errors (i.e., “high precision,” “pass,” and “unqualified”). Two different types of classification schemes have been considered in this study: those that perform feature extraction by using the convolutional neural networks and those based on an explicit feature extraction procedure. The classification accuracy of the popular machine learning methods has been evaluated in comparison with the proposed deep learning model. Based on the experimental data collected during the milling experiments, the proposed model proved to be capable of predicting dimensional accuracy using cutting parameters (i.e., “static features”) and cutting-force data (i.e., “dynamic features”). The average classification accuracy obtained using the proposed deep learning model was 9.55% higher than the best machine learning algorithm considered in this paper. Moreover, the robustness of the hybrid model has been studied by considering the white Gaussian and coherent noises. Hence, the proposed hybrid model provides an efficient way of fusing different sources of process data and can be adopted for prediction of the machining quality in noisy environments.

关键词： precision milling     dimensional accuracy     cutting force     convolutional neural networks     coherent noise    

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Multi-objective optimization of cutting parameters in high-speed milling based on grey relational analysis

Tao FU, Jibin ZHAO, Weijun LIU

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 445-452 doi: 10.1007/s11465-012-0338-z

摘要：

This paper investigates optimization problem of the cutting parameters in high-speed milling on NAK80 mold steel. An experiment based on the technology of Taguchi is performed. The objective is to establish a correlation among spindle speed, feed per tooth and depth of cut to the three directions of cutting force in the milling process. In this study, the optimum cutting parameters are obtained by the grey relational analysis. Moreover, the principal component analysis is applied to evaluate the weights so that their relative significance can be described properly and objectively. The results of experiments show that grey relational analysis coupled with principal component analysis can effectively acquire the optimal combination of cutting parameters and the proposed approach can be a useful tool to reduce the cutting force.

关键词： high-speed milling     grey relational analysis     principal component analysis     parameters optimization    

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Ball milling promoted direct liquefaction of lignocellulosic biomass in supercritical ethanol

Chunyan Yang, Xiaoliang Yuan, Xueting Wang, Kejing Wu, Yingying Liu, Changjun Liu, Houfang Lu, Bin Liang

《化学科学与工程前沿（英文）》 2020年 第14卷 第4期   页码 605-613 doi: 10.1007/s11705-019-1841-0

摘要： In the present work, ball milling was applied for the pretreatment of lignocellulose to obtain high conversion and bio-oil yield in supercritical ethanol. Ball milling substantially decreased the crystallinity and particle size of lignocellulose, thereby improving its accessibility in ethanol solvent. An increased bio-oil yield of 59.2% was obtained for the ball milled camphorwood sawdust at 300°C, compared with 39.6% for the original lignocellulose. Decreased crystallinity significantly benefited the conversion of the cellulose component from 60.8% to 91.7%, and decreased particle size was beneficial for the conversion of all components. The obtained bio-oil had a high phenolic content, as analyzed by gas chromatography-mass spectrometry. Methoxylation and retro-aldol condensation were observed during alcoholysis, and the reaction pathways of lignocellulose in supercritical ethanol were attributed to the action of free radicals.

关键词： ball milling     lignocellulose     supercritical ethanol     liquefaction     bio-oil    

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标题 作者 时间 类型 操作

Machinability of damage-tolerant titanium alloy in orthogonal turn-milling

Tao SUN, Lufang QIN, Junming HOU, Yucan FU

期刊论文

Variable eccentric distance-based tool path generation for orthogonal turn-milling

Fangyu PENG,Wei WANG,Rong YAN,Xianyin DUAN,Bin LI

期刊论文

Investigating the role of exiting vehicles and turn indicator usage in gap acceptance at single-lane

Nathan P. BELZ

期刊论文

Experimental investigation and comparative study of inter-turn short-circuits and unbalanced voltage

Fatima BABAA, Abdelmalek KHEZZAR, Mohamed el kamel OUMAAMAR

期刊论文

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

期刊论文

A novel flavonol-based colorimetric and turn-on fluorescent probe for rapid determination of hydrazine

期刊论文

Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

期刊论文

Cutting Force Model for a Small-diameter Helical Milling Cutter

LI Xiwen, YANG Shuzi, YANG Mingjin, XIE Shouyong

期刊论文

Position-varying surface roughness prediction method considering compensated acceleration in milling

期刊论文

Improved analytical model for residual stress prediction in orthogonal cutting

null

期刊论文

Singularity loci of an orthogonal spherical two-degree-of-freedom parallel mechanism

Jialun YANG, Feng GAO,

期刊论文

Mechanical behavior and semiempirical force model of aerospace aluminum alloy milling using nano biological

期刊论文

A hybrid deep learning model for robust prediction of the dimensional accuracy in precision milling of

期刊论文

Multi-objective optimization of cutting parameters in high-speed milling based on grey relational analysis

Tao FU, Jibin ZHAO, Weijun LIU

期刊论文

Ball milling promoted direct liquefaction of lignocellulosic biomass in supercritical ethanol

Chunyan Yang, Xiaoliang Yuan, Xueting Wang, Kejing Wu, Yingying Liu, Changjun Liu, Houfang Lu, Bin Liang

期刊论文