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Chinese Journal of Aeronautics 2018年第1期31卷 178-186页

作者： Zhengcai ZHAO Jiuhua XU yucan fu Zhiqiang LI College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Beijing Aeronautics Manufacturing Technology Research Institute Beijing 100024 China

Titanium hollow blades are characterized with lightweight and high structural strength, which are widely used in advanced aircraft engines nowadays. Superplastic forming/diffusion bonding （SPF/DB） combined with numerical control （NC） milling is a major solution for manufacturing titanium hollow blades. Due to the shape deviation caused by multiple heat and pressure cycles in the SPF/DB process, it is hard to manufacture the leading and tailing edges by the milling process. This paper presents a new adaptive machining approach using free-form deformation to solve this problem. The actual SPF/DB shape of a hollow blade was firstly inspected by an on-machine measurement method. The measured point data were matched to the nominal SPF/DB shape with an improved ICP algorithm afterwards, by which the point-pairs between the measurement points and their corresponding points on the nominal SPF/DB shape were established, and the maximum modification amount of the final nominal shape was constrained. Based on the displacements between the point-pairs, an accurate FFD volume was iteratively calculated. By embedding the final nominal shape in the deformation space, a new final shape of the hollow blade was built. Finally, a series of measurement and machining tests was performed, the results of which validated the feasibility of the proposed adaptive machining approach.

关键词： Adaptive machining Blade geometry Free-form deformation Reconstruction Titanium

Surface micro-texture on sapphire fabricated by laser ablation trajectory regulation

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Chinese Journal of Aeronautics 2022年第3期35卷 525-536页

作者： Quanli ZHANG Qiwen WANG Zhen ZHANG yucan fu Jiuhua XU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Fabrication of the surface micro-texture on the C-plane sapphire is undertaken by a355 nm Ultraviolet(UV)pulsed *** surface micro-textures of sapphire with different laser scanning line spacing ranging from 10 lm to 100 lm are obtained,where the selection range of scanning line spacing is controlled in the range of the groove width and plasma width to obtain a surface of high Peak-Valley(PV)value.A reasonable processing order is proposed to manufacture different types of surface micro-textures on sapphire by laser ablation trajectory *** the multiple-passes laser ablation of sapphire by the UV nanosecond pulsed laser,the scanning lines in each direction is treated as once *** this basis,the multiple processing can be carried out to avoid the influence of the subsequent scanning on the machined *** addition,the effect of different scanning line spacing on the PV value is quantified and different types of surface microtextures on sapphire,including the squares,the rhombuses and the hexagons,are successfully fabricated,which can be applied in the friction reduction or anti-reflection field.

关键词： Laser ablation trajectory Sapphire Scanning line spacing Surface micro-texture PV values

Tool Wear in Turning of Titanium Alloy after Thermohydrogen Treatment

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 776-780页

作者： WEI Weihua XU Jiuhua fu yucan YANG Shubao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The influence of hydrogen contents on the tool wear has been mainly focused on the flank wear of the common tool,and the influence of hydrogen contents on the rake crater wear（main wear type） of the tool,particularly for the fine granular material tool,has been less investigated *** this paper,for the purpose of researching the influence of hydrogen contents on tool wear,the titanium alloy Ti-6Al-4V is hydrogenated at 800 ℃ by thermohydrogen treatment technology and the turning experiments are carried out by applying uncoated WC-Co cemented carbide *** three-dimensional video microscope is used to take photos and measure tool *** results show that both of crater wear depth（KT） and average flank wear width（VB） firstly decreases and then increases with the increasing of hydrogen *** maximum reducing amplitude of KT and VB is about 50% and 55%,*** the given conditions,the optimum hydrogen content is 0.26%.It is considered that the reduction of cutting temperature is an important factor for improving tool wear after the Ti-6Al-4V alloy is properly ***,the reasons of hydrogen effect on the tool wear are chiefly attributed to comprehensive effect of hydrogen contents on microstructure,physical properties and dynamic mechanical properties of the Ti-6Al-4V *** proposed research provides the basic data for evaluating the machinability of hydrogenation Ti-6Al-4V alloy,and promotes practical application of thermohydrogen treatment technology in titanium alloys.

关键词： titanium alloy hydrogenation cutting temperature crater wear flank wear

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

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Frontiers of Mechanical Engineering 2020年第3期15卷 504-515页

作者： Tao SUN Lufang QIN Junming HOU yucan fu Jiangsu Key Laboratory of Large Engineering Equipment Detection and Control Xuzhou University of TechnologyXuzhou 221111China Industrial Center Nanjing Institute of TechnologyNanjing 211167China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

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

Cold expansion technology of connection holes in aircraft structures:A review and prospect

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Chinese Journal of Aeronautics 2015年第4期28卷 961-973页

作者： fu yucan Ge Ende Su Honghua Xu Jiuhua Li Renzheng College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

As one kind of key anti-fatigue manufacture approaches with simplicity and effectiveness, the hole cold expansion technology satisfies the increasing needs for light weight and durability of aircraft *** can improve the fatigue life by several times at no additional weight *** hole cold expansion technology has been widely used in manufacturing and repairing of both fighters and commercial aircraft, and has become a research hotspot in the strengthening *** recent years, hole cold expansion process methods, residual stress around expanded holes, the behavior of fatigue crack initiation and propagation, and fatigue lives after cold expansion are researched extensively through lots of experiments and finite element simulations.A review on the hole cold expansion technology research status in the last twenty years is presented in this *** the analysis of the current characteristics and defects of the hole cold expansion technology, combined with the actual needs in design and manufacture of new-generation aircraft, development trends and novel research directions are presented for realizing precise and high-efficiency anti-fatigue manufacture.

关键词： Aircraft structure Cold expansion Connection hole Fatigue life Finite element simulation Residual stress

Comparative investigation on high-speed grinding of TiCp/Ti–6Al–4V particulate reinforced titanium matrix composites with single-layer electroplated and brazed CBN wheels

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Chinese Journal of Aeronautics 2016年第5期29卷 1414-1424页

作者： Li Zheng Ding Wenfeng Shen Long Xi Xinxin fu yucan College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

In order to develop the high-efficiency and precision machining technique of TiCp/Ti - 6Al-4V particulate reinforced titanium matrix composites （PTMCs）, high-speed grinding experiments were conducted using the single-layer electroplated cubic boron nitride （CBN） wheel and brazed CBN wheel, respectively. The comparative grinding performance was studied in terms of grinding force, grinding temperature, grinding-induced surface features and defects. The results display that the grinding forces and grinding temperature obtained with the brazed CBN wheel are always lower than those with the electroplated CBN wheel. Though the voids and microcracks are the dominant grinding-induced surface defects, the brazed CBN wheel produces less surface defects compared to the electroplated wheel according to the statistical analysis results. The max mum materials removal rate with the brazed CBN wheel is much higher than that with the electroplated one. All above indicate that the single-layer brazed CBN super-abrasive wheel is more suitable for high-speed grinding of PTMCs than the electroplated counterpart.

关键词： High-speed grinding PTMCs Single-layer brazed CBNwheel Single-layer electroplated CBN wheel Surface defects

Heat Transfer Characteristics outside the Condenser of a Rotating Heat Pipe Grinding Wheel with a Lateral Air Impinging Jet

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Journal of Thermal Science 2021年第2期30卷 493-503页

作者： CHEN Jiajia ZHANG Liyong fu yucan QIAN Ning JIANG Huafei YANG Lin College of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Wind Power Generation Engineering&Technology Center Nanjing 210023China

This study numerically analyzed the heat transfer characteristics outside the condenser of a rotating heat pipe grinding wheel(RHP-GW).The goal of this investigation is to determine the optimal structure and parameters for the condenser section of *** fin height(f=0-7 mm),rotational Reynolds number(Rer=1602-6408)and jet Reynolds number(Rej=42379-108302)were analyzed under input heat flux of 4000 W/m2.A fully developed flow was imposed at the outlet of the *** showed that the optimal heat transfer rate was obtained for fin height of 5 mm,which improved the average Nusselt number by 84%compared to the structure without fins.A critical Rej for each Rer that the impinging jet can reach the condenser section was *** critical Rej value increases with Rer,which is in the range from 42379 to 61215 and 61215 to 80050 for Rer=6408 and Rer=9610,respectively.

关键词： rotating heat pipe grinding wheel impinging jet heat transfer numerical analysis

Grinding behavior and surface appearance of(TiC_p+ TiB_w)/Ti-6Al-4V titanium matrix composites

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Chinese Journal of Aeronautics 2014年第5期27卷 1334-1342页

作者： Ding Wenfeng Zhao Biao Xu Jiuhua Yang Changyong fu yucan Su Honghua College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology

（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.

关键词： Grinding force Grinding temperature Particles Surface appearance Titanium matrix composites

Investigation on the Grindability of CSS-42L Stainless Steel

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第6期33卷 -页

作者： Yang Changyong Xu Jiuhua fu yucan Ding Wenfeng Su Honghua College of Mechanical and Electrical Engineering Nanjing University of Aeronautics & Astronautics

Plunge grinding experiments were carried out on CSS-42L stainless steel with the white fused alumina *** grinding forces were measured with variations in accumulated material removal *** the morphological features of worn grinding wheel were analyzed by optical microscopy and the grinding temperatures were measured with a *** comparison,C45 steel was ground under the same *** results indicated that the grinding forces of CSS-42L were at least twice that of C45 *** the accumulated removal volume overcame 375mm^3,strong adhesion was found between the abrasives and workpiece ***,adhesion was hardly found after 800mm^3 workpiece C45 steel was *** order to enhance the machining property of CSS-42L,a brazed CBN wheel was incorporated into the grinding of CSS-42L,and the grinding forces and temperatures were found significantly decreased,whose maximum decreasing amplitude was about 70%and 80%,respectively.

关键词： CSS-42L grinding force temperature adhesion

Recent Advances in Hole Making of FRP/Metal Stacks:A Review

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 361-375页

作者： CHEN Yan YANG Haojun XU Jiuhua fu yucan YAN Chaoren Jiangsu Key Laboratory of Precision and Micro-manufacturing Technology College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and Astronautics

Weight reduction is a key driving force for materials development in aerospace industry,which leads to extensive usage of lightweight structural materials such as fiber reinforced polymer(FRP),titanium alloy,aluminum alloy,*** making is indispensable to assembling these lightweight components by riveted or bolted ***,hole making of FRP / metal stacks is always the most challenging task due to differences of material properties between FRP and metals.A comprehensive literature review on hole making of FRP/metal stacks in the last decade is given with a focus on four main aspects including drilling operation,drilling damages and machining parameter optimization,tool performance and wear,and developments in hole making ***,in order to ensure the precise and efficient hole making of FRP/metal stacks,an idea of low frequency vibration assisted drilling(LFVAD)FRP/metal stacks based on material removal characteristics is put forward by fully exploiting the unique advantages of LFVAD technology.

关键词： fiber reinforced polymer (FRP)/metal stacks drilling machining quality tool wear helical milling vibration assisted drilling abrasive water jet machining