Open Access. Powered by Scholars. Published by Universities.®
Science and Technology Studies Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Publication
- Publication Type
Articles 31 - 50 of 50
Full-Text Articles in Science and Technology Studies
Formability Of Micro Sheet Hydroforming Of Ultra-Fine Grained Stainless Steel, Hideki Sato, Kenichi Manabe, Daiki Kondo, Dongbin Wei, Zhengyi Jiang
Formability Of Micro Sheet Hydroforming Of Ultra-Fine Grained Stainless Steel, Hideki Sato, Kenichi Manabe, Daiki Kondo, Dongbin Wei, Zhengyi Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
The formability of ultra-fine grained stainless steel is investigated in micro hydromechanical deep drawing. The materials used are ultra-fine grained stainless steel and SUS304-H with thickness of 20 and 50 m. The micro cups are successfully fabricated for the ultra-fine grained stainless steel but it cannot be fabricated for SUS304-H with thickness of 20 μm. The fracture type of ultra-fine grained stainless steel foil is the shortage of tensile strength at plain strain state and does not change with a decrease of the thickness. In contrast, the fracture type of SUS304-H foil changes to the bending deformation with decreasing the …
Numerical Study On Springback With Size Effect In Micro V-Bending, Zhi Fang, Haina Lu, Dongbin Wei, Zhengyi Jiang, Xianming Zhao, Di Wu
Numerical Study On Springback With Size Effect In Micro V-Bending, Zhi Fang, Haina Lu, Dongbin Wei, Zhengyi Jiang, Xianming Zhao, Di Wu
Faculty of Engineering and Information Sciences - Papers: Part A
With the development of microforming technology, the demand on accuracy of the metallic micro components is elevating. While springback phenomenon which is inevitable during bending process, can cause unpredicted dimensional error, bringing difficulties to the downstream assembly, and let alone the springback in microforming as the measurements of tools and workpieces downsize hundreds even thousands times. This paper focuses on the springback effect that occurs after the micro Vbending a classic processing method to manufacture microparts. Numerical simulation has been conducted to investigate the size effect in terms of Voronoi tessellation and springback. A finite element (FE) model of the …
Potential Of Fluid Pressure Use For Achieving High Formability In Micro Sheet Forming Process, Hideki Sato, Kenichi Manabe, Dongbin Wei, Zhengyi Jiang, Daiki Kondo
Potential Of Fluid Pressure Use For Achieving High Formability In Micro Sheet Forming Process, Hideki Sato, Kenichi Manabe, Dongbin Wei, Zhengyi Jiang, Daiki Kondo
Faculty of Engineering and Information Sciences - Papers: Part A
This study decsribesa potential offluid pressure in micro hydromechanical deep drawingto achieve high formability. The FE simulation is carried out using the stainless steel foil with 50μm thickness. The friction holding effect can be obtained by applying the fluid pressure and it becomes high at high D p/t in MHDD. By applying the counter and radial pressure in MHDD, the desired lubrication condition can be obtained and the friction force can be reduced. By the friction holding effect and lubrication effect in MHDD, the micro cups can be successful fabricated in MHDD. Consequently, it is clarify that the fluid pressure …
Deformation Characterization Of Micro Rolling For Stainless Steel Foil, Haibo Xie, Kenichi Manabe, Tsuyoshi Furushima, Kazuo Tada, Zhengyi Jiang
Deformation Characterization Of Micro Rolling For Stainless Steel Foil, Haibo Xie, Kenichi Manabe, Tsuyoshi Furushima, Kazuo Tada, Zhengyi Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
Physical parameters such as microscopic roughness become very important in micro forming process due to increasing surface to volume ratio. As a very important phenomenon in metal forming process, friction size effects are becoming more attracting for researchers because traditional models are not reliable. In this study, the micro rolling deformation characterization has been investigated with SUS 304 stainless steel considering the effect of lubricant, and there exists a sticking area in the contact zone. The evolution of surface roughness and oil film thickness are analyzed. The foil thickness plays an important role in the tribological features of rolling. All …
Surface Morphology Of Micro Stepped Components In Micro Cross Wedge Rolling, Dongbin Wei, Haina Lu, Zhengyi Jiang, Kenichi Manabe
Surface Morphology Of Micro Stepped Components In Micro Cross Wedge Rolling, Dongbin Wei, Haina Lu, Zhengyi Jiang, Kenichi Manabe
Faculty of Engineering and Information Sciences - Papers: Part A
A novel microforming process - Micro Cross Wedge Rolling has been proposed, which is very promising in producing micro stepped components. It is inevitable to confront with huge challenges in the development of micro cross wedge rolling technology. The influences of miniaturization, especially size effect, on process, accuracy control and product quality have to be studied. A micro cross wedge rolling testing rig has been designed and manufactured. Micro stepped components have been fabricated successfully by adopting flat wedge tools on this rig. The effects of surface roughness of tool, grain size in workpiece and cross sectional area reduction on …
Optimisation Of Size-Controllable Centroidal Voronoi Tessellation For Fem Simulation Of Micro Forming Processes, Liang Luo, Zhengyi Jiang, Haina Lu, Dongbin Wei, Kezhi Linghu, Xianming Zhao, Di Wu
Optimisation Of Size-Controllable Centroidal Voronoi Tessellation For Fem Simulation Of Micro Forming Processes, Liang Luo, Zhengyi Jiang, Haina Lu, Dongbin Wei, Kezhi Linghu, Xianming Zhao, Di Wu
Faculty of Engineering and Information Sciences - Papers: Part A
Voronoi tessellation has been employed to characterise material features in Finite Element Method (FEM) simulation, however, a poor mesh quality of the voronoi tessellations causes problems in explicit dynamic simulation of forming processes. Although centroidal voronoi tessellation can partly improve the mesh quality by homogenisation of voronoi tessellations, small features, such as short edges and small facets, lead to an inferior mesh quality. Further, centroidal voronoi tessellation cannot represent all real micro structures of materials because of the almost equal tessellation shape and size. In this paper, a density function is applied to control the size and distribution of voronoi …
Finite Element Method Analysis Of Micro Cross Wedge Rolling Of Metals, Zhengyi Jiang, Haina Lu, Dongbin Wei, Kezhi Linghu, Xianming Zhao, Xiaoming Zhang, Di Wu
Finite Element Method Analysis Of Micro Cross Wedge Rolling Of Metals, Zhengyi Jiang, Haina Lu, Dongbin Wei, Kezhi Linghu, Xianming Zhao, Xiaoming Zhang, Di Wu
Faculty of Engineering and Information Sciences - Papers: Part A
A newly developed manufacturing technology - micro cross wedge rolling technology is an appropriate method to produce micro axisymmetric components such as micro stepped shafts. The development of this classic cold forming process is limited by a lack of sufficient understanding of geometric and material effects due to the size reduction of the components. In this study, a numerical model is proposed to simulate micro cross wedge rolling where the grain size effect is taken into account. Pure copper is chosen as the raw material. A finite element simulation is implemented where the diameter of the cylindrical workpiece is 0.8 …
Numerical Modeling Of Size Effect In Micro Hydromechanical Deep Drawing, Hideki Sato, Ken-Ichi Manabe, Dongbin Wei, Zhengyi Jiang
Numerical Modeling Of Size Effect In Micro Hydromechanical Deep Drawing, Hideki Sato, Ken-Ichi Manabe, Dongbin Wei, Zhengyi Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
A modeling of tribological size effects in micro deep drawing (MDD) and micro hydromechanical deep drawing (MHDD) is a main focus in this study. The inner and outer pockets in which the different friction coefficients can be applied at different lubrication conditions are considered on the blank surface. The ratio of the area of outer pockets to inner pockets is changed with the decrease in the size. The low friction coefficient at the outer pockets is assumed in MHDD by considering the lubrication effect of fluid medium. The numerical analysis is performed under six lubrication conditions. The analytical results of …
Inertial Particle Separation By Differential Equilibrium Positions In A Symmetrical Serpentine Micro-Channel, Jun Zhang, Sheng Yan, Ronald Sluyter, Weihua Li, Gursel Alici, Nam-Trung Nguyen
Inertial Particle Separation By Differential Equilibrium Positions In A Symmetrical Serpentine Micro-Channel, Jun Zhang, Sheng Yan, Ronald Sluyter, Weihua Li, Gursel Alici, Nam-Trung Nguyen
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents an inertial microfluidic device with a simple serpentine micro-channel to continuously separate particles with high performance. Separation of micro/nano-particles has a variety of potential applications in biomedicine and industry. Among the existing separation technologies, a label-free technique without the use of antibody affinity, filter or centrifugation is highly desired to ensure minimal damage and alteration to the cells. Inertial microfluidics utilising hydrodynamic forces to separate particles is one of the most suitable label-free technologies with a high throughput. Our separation concept relies on size-based differential equilibrium positions of the particles perpendicular to the flow. Highly efficient separation …
An Active-Compliant Micro-Stage Based On Eap Artificial Muscles, Rahim Mutlu, Gursel Alici, Xingcan Xiang, Weihua Li
An Active-Compliant Micro-Stage Based On Eap Artificial Muscles, Rahim Mutlu, Gursel Alici, Xingcan Xiang, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Electroactive Polymer actuators (EAPs), also known as EAP artificial muscles, offer a great potential for soft robotics. They are suitable for bio-inspired robotic applications due to their built-in actuation property within the mechanical body. In this paper, we report on a fully compliant micro-stage with built-in actuation. It has been fabricated as one piece inspired from twining structures in nature. We have employed a soft robotic modeling approach and finite element modeling to predict the mechanical output of the stage as a function of the input voltage. Experiments were conducted under a range of electrical inputs (0.25-1.00 V). For a …
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Shi Xue Dou
Electron-phonon coupling strength was studied in graphene-MgB2 composites to explore the possibilities for a higher superconducting transition temperature (Tc). For the first time in the experimental work on MgB2, the Raman active E2g mode was split into two parts: a softened mode corresponding to tensile strain and a hardened mode attributed to the carbon substitution effect. The tensile strain effect is suggested to improve Tc of graphene-MgB2 composites because it increases the electron-phonon coupling strength of MgB2.
Fabrication And Characterization Of A Polymer Micro-Fiber Bragg Grating, Ginu Rajan, Gang-Ding Peng
Fabrication And Characterization Of A Polymer Micro-Fiber Bragg Grating, Ginu Rajan, Gang-Ding Peng
Faculty of Engineering and Information Sciences - Papers: Part A
Polymer micro-fibers with inscribed Bragg gratings are reported in this paper. By implementing a two-stage fabrication process a 16 μm diameter micro-fiber is fabricated with an inscribed 10 mm long Bragg grating which exhibits a peak reflected wavelength circa 1530 nm. The growth dynamics of the polymer micro-fiber Bragg grating are also observed and analyzed. A maximum reflectivity of 5% is obtained after an exposure time of 3 minutes to a 50 mW power He-Cd laser of 325 nm wavelength. The temperature characterization of the micro-fiber Bragg grating with different diameters is also presented. The fabricated micro-fiber Bragg grating can …
A Micro Deep Drawing Of Arb Processed Aluminium Foil Aa1235, Syamsul Hadi, A Kiet Tieu, Cheng Lu, Hongtao Zhu
A Micro Deep Drawing Of Arb Processed Aluminium Foil Aa1235, Syamsul Hadi, A Kiet Tieu, Cheng Lu, Hongtao Zhu
Faculty of Engineering and Information Sciences - Papers: Part A
The flow stress of AA1235 aluminium series-H14 material of 16 to 300 μm thickness has been determined here for the first time which showed the stress reduced significantly with thickness. A stress-strain relationship has been determined as a function of the thickness and grain size. A limiting drawing ratio (LDR) of 2.003 was achieved by a subsequent heat treatment of accumulative roll bonded (ARB) materials before the micro-cup drawing. The cup was successfully formed as the combined process has reduced the planar anisotropy, increased the normal anisotropy and improved the formability of a cup.
Finite Element Modelling Of Surface Roughness Transfer And Oxide Scale Micro Deformation In Metal Manufacturing Process, Zhengyi Jiang, Dongbin Wei, Hejie Li
Finite Element Modelling Of Surface Roughness Transfer And Oxide Scale Micro Deformation In Metal Manufacturing Process, Zhengyi Jiang, Dongbin Wei, Hejie Li
Faculty of Engineering and Information Sciences - Papers: Part A
In the paper, the micro deformation of oxide scale in hot strip rolling has been investigated with considering the friction effect. The finite element simulation of the micro deformation of oxide scale has been successfully conducted, and the calculated surface roughness is compared with the measured value, which shows a good agreement. A crystal plasticity finite element method (CPFEM) model was also successfully developed to analyse the surface roughness transfer during metal manufacturing. The simulation results show a good agreement with the experimental results in the flattening of surface asperity, and the surface roughness decreases significantly with an increase of …
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Graphene Micro-Substrate Induced High Electron-Phonon Coupling In Mgb2, W X. Li, X Xu, K S. B De Silva, F X. Xiang, S X. Dou
Faculty of Engineering and Information Sciences - Papers: Part A
Electron-phonon coupling strength was studied in graphene-MgB2 composites to explore the possibilities for a higher superconducting transition temperature (Tc). For the first time in the experimental work on MgB2, the Raman active E2g mode was split into two parts: a softened mode corresponding to tensile strain and a hardened mode attributed to the carbon substitution effect. The tensile strain effect is suggested to improve Tc of graphene-MgB2 composites because it increases the electron-phonon coupling strength of MgB2.
Self-Assembly Of Hierarchical Star-Like Co3o4 Micro/Nanostructures And Their Application In Lithium Ion Batteries, Li Li, Kuok Hau Seng, Zhixin Chen, Zaiping Guo, Hua-Kun Liu
Self-Assembly Of Hierarchical Star-Like Co3o4 Micro/Nanostructures And Their Application In Lithium Ion Batteries, Li Li, Kuok Hau Seng, Zhixin Chen, Zaiping Guo, Hua-Kun Liu
Faculty of Engineering and Information Sciences - Papers: Part A
A novel hierarchical star-like Co3O4 was successfully synthesized from self-assembled hierarchical Co(OH)F precursors via a facile hydrothermal method and subsequent annealing in air. The morphological evolution process of the Co(OH)F precursors was investigated by examining the different reaction times during synthesis. First, hexagonal plates are formed, and then nanodiscs grow on the surface of the plates. Subsequently, dissolution and regrowth of Co(OH)F occur to form the star-like hierarchical structures. Co3O4 obtained from thermal decomposition of the Co(OH)F precursor in air at 350 °C exhibited high reversible capacity as an anode material in lithium ion batteries. The specific charge capacity of …
Analysis Of Axisymmetric Cup Forming Of Metal Foil And Micro Hydroforming Process, Hideki Sato, Kenichi Manabe, Dongbin Wei, Zhengyi Jiang
Analysis Of Axisymmetric Cup Forming Of Metal Foil And Micro Hydroforming Process, Hideki Sato, Kenichi Manabe, Dongbin Wei, Zhengyi Jiang
Faculty of Engineering and Information Sciences - Papers: Part A
A novel forming method "micro hydromechanical deep drawing (MHDD)" is focused to improve the tribological property and forming limit. In this study, a theoretical model for MHDD is developed to investigate the size effect on deformation behavior in micro hydromechanical deep drawing. The effects of fluid pressure, the difference of friction coefficients at inner pockets and outer pockets are considered in the investigation on the size effect of tribological property. The friction force decreases as the scale factor decreases in MHDD process. It is also found that the tribological property in micro scale can be improved by applying the fluid …
Simulation Of Defects In Micro-Deep Drawing Of An Aluminium Alloy Foil, Syamsul Hadi, Hai-Liang Yu, Kiet Tieu, Cheng Lu
Simulation Of Defects In Micro-Deep Drawing Of An Aluminium Alloy Foil, Syamsul Hadi, Hai-Liang Yu, Kiet Tieu, Cheng Lu
Faculty of Engineering and Information Sciences - Papers: Part A
Micro-forming refers to the application of conventional forming processes to manufacture products from ultra-thin sheet materials. While attempting to meet the increasing demand for cost-effective manufacturing of micro-formed components, it is very important to reduce the defects in the products. In this paper, we report a number of Finite Element (FE) simulations of the micro-deep drawing process with various sample thicknesses and eccentric distances. The simulations indicated that when the sample thickness is nearly equal to the gap between the plunger and the die, the sample is likely to develop fractures at the bottom corner. When the sample thickness is …
Study On The Influence Of Temperature On The Surface Asperity In Micro Cross Wedge Rolling, H N. Lu, D B. Wei, Z Y. Jiang, D Wu, X M. Zhao
Study On The Influence Of Temperature On The Surface Asperity In Micro Cross Wedge Rolling, H N. Lu, D B. Wei, Z Y. Jiang, D Wu, X M. Zhao
Faculty of Engineering and Information Sciences - Papers: Part A
When the common deformation processes are scaled down to micro/meso dimensions, size effect is the particular phenomena in microforming, which is related to the dominant influence of single grains inside the micropart. The conventional cross wedge rolling (CWR) is introduced into the micro scale in order to take the advantages of CWR. The micro cross wedge rolling (MCWR) has to confront with the phenomena of size effect that occurs in the common microforming processes inevitably. One of the approaches to compensate size effect is to increase the deforming temperature. An increased formability is achieved because more slip systems of polycrystal …
An Image-Based Approach For Classification Of Human Micro-Doppler Radar Signatures, Fok Hing Chi Tivive, Son Lam Phung, Abdesselam Bouzerdoum
An Image-Based Approach For Classification Of Human Micro-Doppler Radar Signatures, Fok Hing Chi Tivive, Son Lam Phung, Abdesselam Bouzerdoum
Faculty of Engineering and Information Sciences - Papers: Part A
With the advances in radar technology, there is an increasing interest in automatic radar-based human gait identification. This is because radar signals can penetrate through most dielectric materials. In this paper, an image-based approach is proposed for classifying human micro-Doppler radar signatures. The time-varying radar signal is first converted into a time-frequency representation, which is then cast as a two-dimensional image. A descriptor is developed to extract micro-Doppler features from local time-frequency patches centered along the torso Doppler frequency. Experimental results based on real data collected from a 24-GHz Doppler radar showed that the proposed approach achieves promising classification performance.