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Chatter stability and precision during high-speed ultrasonic vibration cutting of a thin-walled titanium cylinder

Chinese Journal of Aeronautics 2020年第12期33卷 3535-3549页

作者： Zhenlong PENG deyuan zhang Xiangyu zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China Institute of Bionic and Micro-Nano Systems Beihang UniversityBeijing 100083China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100083China

Titanium alloys are widely used in the aviation and aerospace industries due to their unique mechanical and physical ***,thin-walled titanium(Ti)cylinders have received increasing attention for their applications as rocket engine casings,aircraft landing gear,and aero-engine hollow shaft due to their observed improvement in the thrust-to-weight ***,the conventional cutting(CC)process is not appropriate for thin-walled Ti cylinders due to its low thermal conductivity,high strength,and low ***,high-speed ultrasonic vibration cutting(HUVC)assisted processing has recently proved highly effective for Ti-alloy *** this study,HUVC technology is employed to perform external turning of a thinwalled Ti cylinder,which represents a new application of ***,the kinematics,tool path,and dynamic cutting thickness of HUVC are ***,the phenomenon of mode-coupling chatter is analyzed to determine the effects and mechanism of HUVC by establishing a critical cutting thickness *** can increase the critical cutting thickness and effectively reduce the average cutting force,thus reducing the energy intake of the ***,comparison experiments are conducted between HUVC and CC *** results indicate that the diameter error rate is 10%or less for HUVC and 51%for the CC method due to a 40%reduction in the cutting *** addition,higher machining precision and better surface roughness are achieved during thin-walled Ti cylinder manufacturing using HUVC.

关键词： High-speed machining Minimum chip thickness Mode-coupling Thin-walled cylinder Ultrasonic vibration cutting

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Investigation of the Anisotropic Morphology-Induced Effects of the Slippery Zone in Pitchers of Nepenthes alata

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Journal of Bionic Engineering 2015年第1期12卷 79-87页

作者： Pengfei zhang Huawei Chen deyuan zhang School of Mechanical Engineering and Automation Beihang University Beijing 100191 China

Plant of carnivorous genus Nepenthes alata has evolved specific pitchers to prey insects for survival in the barren habitat, especially its slippery zone. The excellent slippery function has received considerable interest because of its potential applica- tion in antifriction surface design. The surface morphologies of intact and de-waxed slippery zones were characterized using scanning electron microscope and scanning white-light interferometer. Hierarchical structures with anisotropic micro- lunate structure and nano- wax crystals were found on the slippery zone. Due to the hierarchical structures, the slippery zone is hy- drophobic. It shows a significant anisotropic wettability with static contact angles 153.3° and 140.1° in the directions perpen- dicular and parallel to the upward direction （toward the peristome）, respectively. The sliding angles are -3° and -10° in the downward and upward directions, respectively. Crawling experiments indicate that the microscopic surface roughness and the brittleness of the wax crystals may reduce insect attachment in different modes according to the insect mass differences. Moreover, artificial slippery surfaces inspired by the slippery zone of Nepenthes alata were fabricated. Traction experiments quantitatively verified that the friction force of replicated lunate structures with Ra-2.54 μm surface roughness was reduced by about 25% as compared to flat surface with Ra-0.56 μm surface roughness for cricket claws.

关键词： biomimetic surface anisotropic wettability antifriction slippery surface Nepenthes alata

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Study on the micro-replication of shark skin

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Science China(Technological Sciences) 2008年第7期51卷 890-896页

作者： HAN Xin zhang deyuan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China

Direct replication of creatural scarfskins to form biomimetic surfaces with relatively vivid morphology is a new attempt of the bio-replicated forming technology at animal body. Taking shark skins as the replication templates, and the micro-embossing and micro-molding as the material forming methods, the micro-replicating technology of the outward morphology on shark skins was demonstrated. The preliminary analysis on replication precision indicates that the bio-replicated forming technology can replicate the outward morphology of the shark scales with good precision, which validates the application of the bio-replicated forming technology in the direct morphology replication of the firm creatural scarfskins.

关键词： shark skin biomimetic surface bio-replicated forming micro-replication

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Magnetization of microorganism cells by thermal decomposition method

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Science China(Technological Sciences) 2011年第5期54卷 1275-1280页

作者： zhang deyuan zhang WenQiang CAI Jun Bionic and Micro/Nano/Bio Manufacturing Technology Research Center Beihang University Beijing 100191 China

The bio-limited forming technology, a new technology organically integrating microbiology, manufacturing science and materials science, is used in the manufacturing of magnetic or conductive microstructures of different standard shapes. This paper explores the feasibility of magnetizing microorganism with thermal decomposition method. The principle of thermal decomposition of iron pentacarbonyl has been adopted to investigate the cells of Spirulina (a type of nature micro-helical microorganism) coated with pure iron. Further analysis have been conducted on the observations results of hollow micro-helical magnetic particles form, components and the phase structure obtained by using various tools including optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray detector (EDX), transmission electron microscopy (TEM), and X-ray diffraction analysis (XRD). Results showed that Spirulina cells could be coated with iron particles after the completion of thermal decomposition process, with well-kept shape of natural helixes and consistent components of different sampling points on the surface layer and thickness of layer. After the heat treatment at 700°C, the type of the surface iron layer formed was α-Fe. The paper also investigates the kinetics of the cell magnetization technology by thermal decomposition.

关键词： bio-manufacturing bio-limited forming hollow micro-helical magnetic particles Fe(CO)5 thermal decomposition

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Structural and Mechanical Characterization ofAtrina Pectinata and Freshwater Mussel Shells

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Journal of Bionic Engineering 2015年第2期12卷 276-284页

作者： Jianlu Lv Yonggang Jiang deyuan zhang School of Mechanical Engineering and Automation Beihang University Xueyuan Road No. 37 Haidian District Beij'ing 1 00191 China International Research Institute for Multidisciplinary Science Beihang University Xueyuan Road No. 37 Haidian District Belling 100191 China

The microstructures ofAtrina pectinata and freshwater mussel shells are investigated by optical microscopy and scanning electron microscopy. The mechanical properties of these shells are characterized by nanoindentation and three-point bending tests. Results show that both shells possess a prismatic microstructure mainly composed of columnar crystals and an organic matrix. The fracture toughness of the prismatic structure of Atrina pectinata and freshwater mussel are approximately 1.15 MPa.m1/2 and 0.87 MPa.m1/2, respectively, while the fracture toughness of natural calcite is approximately 0.2 MPa.m1/2. Calculated results from indentations agree with those obtained from the three-point bending tests. The columnar crystal material shows excellent fracture toughness due to grain refinement. In addition, the organic matrix of the prismatic layer can arrest cracks, and thereby improves the fracture toughness.

关键词： shell prismatic fracture toughness organic matrix crack

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Applications of bioinspired approaches and challenges inmedical devices

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Bio-Design and Manufacturing 2021年第1期4卷 146-148页

作者： Huawei Chen Yi zhang Liwen zhang Xilun Ding deyuan zhang School of Mechanical Engineering and Automation Beihang UniversityBeijingChina Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijingChina

Urgent requirements of medical devices Precision medicine has gradually become a development strategy in many countries and attracted worldwide attention in recent years due to the increasing concerns in public *** the definition of precision medicine has less or more difference from the viewpoints of different fields,the demands on the properties of medical devices or medical materials involving biocompatibility and anti-thrombosis are gradually growingmuch more diverse and much more urgent than ever[1].This trend brings up many new research topics about materials,mechanical systems and sensors to develop advanced medical *** to design and on-demand fabricate the bio-materials,bio-interface and bio-systems to meet the urgent demands of medical devices is still a challenge for us.

关键词： interface urgent viewpoint

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Morphology and Mechanical Properties of Vibratory Organs in the Leaf-cutting Ant （Atta cephalotes）

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Journal of Bionic Engineering 2018年第4期15卷 722-730页

作者： Guang Yao Lin Feng deyuan zhang Xinggang Jiang School of Mechanical Engineering and Automation Beihang University Beijing 100191 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100083 China

The ultrasonic scalpel has a number of excellent properties; however, its use in in vivo surgery is limited since the scalpel is not flexible enough. Changing the mechanism of ultrasonic vibration can allow the ultrasonic scalpel to bend. This paper reveals the mecha- nism of vibration generation of leaf-cutting ants, which is based on the microstructural and mechanical properties of special organs that produce the vibrations. Mierostructural characteristics of cross-sections of the vibratory organ of Atta cephalotes were observed using scanning electron microscopy. It was found that the scraper perfectly matches the file plate dorsoventrally; however, the file teeth cannot catch the scraper. An exploration of the kinematics of the file-scraper device was subsequently carried out to reveal a face-to-face contact mode, facilitating a gentler engagement process. For the first time, the mechanism of vibration generation of leaf-cutting ants was inves- tigated using a laser micrometer and high-speed camera. Results reveal the file-scraper device significantly amplifies the input frequency by 125 times, and magnification depends mainly on the tooth spacing and speed of engagement. Finally, nanoindentation tests were performed on file and scraper samples. The results show that they have similar mechanical properties, which greatly reduces friction and wear. This paper may provide theoretical guidance for the develooment of bionic vibration generators.

关键词： leaf-cutting ant vibration mechanism file-scraper device nano-indentation

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The Prey Capture Mechanism of Micro Structure on the Sarracenia Judith Hindle Inner Surface

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Journal of Bionic Engineering 2018年第1期15卷 34-41页

作者： Yang Gan Huawel Chen Tong Ran Pengfei zhang deyuan zhang School of Mechanical Engineering and Automation Beihang University Beijing 1 O0191 China

Low friction surface has attracted considerable attention due to its potential application in various fields. As a typical carnivorous plant, Sarracenia Judith Hindle possesses unique slippery surface to capture prey especially in wet environment. In order to make clear the low friction mechanism, structural characterization was carried out and unique inclined micro-thorn structure was found on the inner wall surface. Micro-droplets harvest on the surface of the micro-thorn was discovered via the observation in wet environment. Friction force measurement was conducted by sliding the ants＇ footpad on the inner surface and polymer replica surfaces, which demonstrated that the friction force decreases on those surfaces in wet environment or inward direction. Further analysis manifested that the slippery inner surface grown with hierarchical micro-thorn structure leads to the friction decrease, and that is the fundamental mechanism for prey capture and retention in the pitcher of carnivorous plant Sarracenia Judith Hindle.

关键词： prey capture hierarchical microstructure Sarracenia low friction surface anisotropic structure

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Effects of Multi-walled Carbon Nanotubes on the Electromagnetic Absorbing Characteristics of Composites Filled with Carbonyl Iron Particles

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Journal of Materials Science & Technology 2012年第1期28卷 34-40页

作者： Yonggang Xu deyuan zhang Jun Cai Liming Yuan Wenqiang zhang Bionic and Micro/Nano/Bio Manufacturing Technology Research Center School of Mechanical Engineering and AutomationBeihang UniversityBeijing 100191China

The electromagnetic （EM） wave absorbing property of silicone rubber filled with carbonyl iron particles （CIPs） and multi-walled carbon nanotubes （MWCNTs） was examined. Absorbents including MWCNTs and spherical/ flaky CIPs were added to silicone rubber using a two-roll mixer. The complex permittivity and complex permeability were measured over the frequency range of 1-18 GHz. The two EM parameters were verified and the uniform dispersion of MWCNTs and ClPs was confirmed by comparing the measured reflection loss （RL） with the calculated one. As the MWCNT weight percent increased, the RL of the spherical CIPs/silicone rubber composites changed insignificantly. It was attributed to the random distribution of spherical ClPs and less content of MWCNTs. On the contrary, for composites filled with flaky ClPs the absorption bandwidth increased at thickness 0.5 mm （RL value lower than -5 dB in 8-18 GHz） and the absorption ratio increased at lower frequency （minimum -35 dB at 3.5 GHz）. This effect was attributed to the oriented distribution of flaky CIPs caused by interactions between the two absorbents. Therefore, mixing MWCNTs and flaky CIPs could achieve wider-band and higher-absorption ratio absorbing materials.

关键词： Absorbing materials Carbon nanotubes Carbonyl iron particles Composites Reflection loss

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Microwave Absorption and Shielding Property of Composites with FeSiAl and Carbonous Materials as Filler

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Journal of Materials Science & Technology 2012年第10期28卷 913-919页

作者： Wenqiang zhang Yonggang Xu Liming Yuan Jun Cai deyuan zhang Bionic and Micro/Nano/Bio Manufacturing Technology Research Center School of Mechanical Engineering and Au-tomationBeihang UniversityBeijing 100191~China

Silicone rubber composites filled with FeSiAI alloys and multi-walled carbon nanotubes （MWCNT）/graphite have been prepared for the first time by a coating process. The complex permittivity and permeability of the composites were measured with a vector network analyzer in a 1-4 GHz frequency range, and the DC electric conductivity was measured by a standard four-point contact method. These parameters were then used to calculate the reflection loss （RL） and shielding effectiveness （SE） of the composites. The results showed that the added MWCNT increased the permittivity and permeability of composites in the L-band, while the added graphite increased only the permittivity. The variation lies in the interactions between two carbonous absorbents. Addition of 1 wt% MWCNT enhanced the RL in the L-band （minimum -5.7 dB at 1 ram, -7.3 dB at 1.5 ram）, while the addition of graphite did not. Addition of MWCNT as well as graphite reinforced the shielding property of the composites （maximum SE 13.3 dB at 1 ram, 18.3 dB at 1.5 ram） owing to the increase of conductivity. The addition of these carbonous materials could hold the promise of enforcing the absorption and shielding property of the absorbers.

关键词： Absorbing materials Electromagnetic Reflection loss Shielding effectiveness

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