INVESTIGATION OF THE SEMISOLID MECHANICAL STIRRING METHOD TO DEPOSIT AN ALUMINUM PARTICLE COATING ON THE SURFACE OF SiC SHORT FIBERS

2004 ◽  
Vol 11 (02) ◽  
pp. 205-210 ◽  
Author(s):  
XIAOHUA QIN ◽  
DONGLIANG JIANG ◽  
SHAOMING DONG
Keyword(s):  
Aluminum Particle ◽  
Pure Aluminum ◽  
Single Layer ◽  
Optical Microscope ◽  
Composite Fiber ◽  
Short Fibers ◽  
Aluminum Particles ◽  
Element Analysis ◽  
Axial Section ◽  
Mechanical Stirring

SiC short fibers, with an average diameter of 13 μm and length of 300–500 μm and chopped from SiC continuous fibers, were surface-modified by the semisolid mechanical stirring method to produce a discrete coating of aluminum particles. The SiC short fibers were introduced into semisolid state aluminum to prepare a slurry by the mechanical stirring method. As all of the short fibers were uniformly dispersed in the slurry, the temperature of the slurry was decreased as quickly as possible, but the slurry continued to be stirred until all of it was converted quickly into a powder-like composite. The surface morphology and axial section of the composite fiber and aluminum particles were examined using a scanning electron microscope (SEM) and an optical microscope; the element analysis of particles on the surface of short fibers in nanometer and submicron sizes was performed by Auger electron spectroscopy (AES). The results indicated that the powder-like composite was a mixture of pure aluminum powder and SiC short composite fiber, the surface of the composite fiber was coated by a discrete single layer of aluminum particles with nanometer, submicron and micron sizes, and the surface coverage of the aluminum particles on the surface of the short fibers ranged from 20 to 30%.

FEASIBILITY OF Al/Al2O3 COMPOSITE PARTICLES PREPARED BY SEMI-SOLID MECHANICAL STIRRING METHOD

2005 ◽  
Vol 12 (04) ◽  
pp. 549-554
Author(s):  
X. H. QIN ◽  
B. L. XIAO ◽  
S. M. DONG ◽  
D. L. JIANG
Keyword(s):  
Composite Powder ◽  
Volume Fraction ◽  
Pure Aluminum ◽  
Liquid Aluminum ◽  
Single Layer ◽  
Optical Microscope ◽  
Composite Particles ◽  
Aluminum Particles ◽  
Mechanical Stirring ◽  
Semi Solid

A discrete coating of aluminum particles on the surface of Al 2 O 3 particles was prepared by the semi-solid mechanical stirring method. Al 2 O 3 particles with an average diameter of 80 μm, preheated to about 300°C, were added to semi-solid pure aluminum to prepare a slurry by the mechanical stirring method. The volume fraction of Al 2 O 3 particles in the slurry was about 20%. As the ceramic particles were uniformly dispersed in the semi-solid aluminum, the temperature of the slurry decreased quickly, but the slurry continued to be stirred until all the slurry was converted into composite powder. The composite powder was then cooled down to room temperature in a steel block cooler in an argon atmosphere. The surface morphology and transverse sections of the composite powder were examined using a scanning electron microscope (SEM), electron probe X-ray microanalyser (EPMA), optical microscope and augur electron spectroscopy (AES). The results indicate that the composite powder was a mixture of Al/Al 2 O 3composite particles and pure aluminum powder in quasi-spherical shapes. A single layer of nano-, submicron- and micron-sized aluminum particles were coated on the surfaces of the Al 2 O 3 particles. The slurry could be converted into the composite powder resulting from faster solidification of liquid aluminum and mechanical stirring.

Finite Element Modeling of Damage Formation in Rubber-Toughened Polymer

2005 ◽  
Vol 297-300 ◽  
pp. 1019-1024
Author(s):  
Mitsugu Todo ◽  
Yoshihiro Fukuya ◽  
Seiya Hagihara ◽  
Kazuo Arakawa
Keyword(s):  
Finite Element ◽  
Damage Zone ◽  
Damage Model ◽  
Crack Tip ◽  
Optical Microscope ◽  
Toughening Mechanism ◽  
Element Analysis ◽  
Zone Formation ◽  
Macro Scale ◽  
Rubber Toughened

Microscopic studies on the toughening mechanism of rubber-toughened PMMA (RTPMMA) were carried out using a polarizing optical microscope (POM) and a transmission electron microscope (TEM). POM result showed that in a typical RT-PMMA, a damage zone was developed in the vicinity of crack-tip, and therefore, it was considered that energy dissipation due to the damage zone development was the primary toughening mechanism. TEM result exhibited that the damage zone was a crowd of micro-crazes generated around rubber particles in the vicinity of notch-tip. Finite element analysis was then performed to simulate such damage formations in crack-tip region. Macro-scale and micro-scale models were developed to simulate damage zone formation and micro-crazing, respectively, with use of a damage model. It was shown that the damage model introduced was successfully applied to predict such kind of macro-damage and micro-craze formations.

scholarly journals Measurements in Solid Propellant Plumes at Ambient Conditions

2011 ◽  
Author(s):  
Jonathan L. Height ◽  
Burl A. Donaldson ◽  
Walter Gill ◽  
Christian G. Parigger
Keyword(s):  
Temperature Distribution ◽  
Solid Propellant ◽  
Aluminum Particle ◽  
Burning Surface ◽  
Ambient Conditions ◽  
Aluminum Particles ◽  
Open Atmosphere ◽  
Particle Ignition ◽  
Accident Scenarios ◽  
Color Pyrometer

The study of aluminum particle ignition in an open atmosphere propellant burn is of particular interest when considering accident scenarios for rockets carrying high-value payloads. This study investigates the temperature of an open atmosphere Atlas V solid propellant burn as a function of height from the burning surface. Two instruments were used to infer this temperature: a two-color pyrometer and a spectrometer. The spectra were fitted to a model of energy states for aluminum monoxide. The temperature which provided the best match between the model and data was taken as the reaction temperature. Emissions above 30 inches from the surface of the propellant were not sufficiently strong for data reduction, perhaps obscured by the alumina smoke cloud. The temperature distribution in the plume increased slightly with distance from the burning surface, presumably indicating the delay in ignition and heat release from the larger aluminum particles in the propellant. The pyrometer and spectrometer results were found to be in excellent agreement indicating plume temperatures in the range of 2300K to 3000K.

scholarly journals Design, fabrication and experimental studies of compliant flexure diaphragm for micro pump

2018 ◽  
Vol 7 (2.21) ◽  
pp. 66 ◽  
Author(s):  
R Roopa ◽  
P Navin Karanth ◽  
S M. Kulkarni
Keyword(s):  
Polyvinylidene Fluoride ◽  
High Performance ◽  
Experimental Studies ◽  
Single Layer ◽  
Operating Voltage ◽  
Driving Voltage ◽  
Element Analysis ◽  
Central Deflection ◽  
Large Numbers ◽  
Micro Pump

This study reports the performance of piezo actuated compliant flexure diaphragm for micropump and MEMS application. To achieve the high performance of diaphragm at the low operating voltage compliant flexure diaphragm design is introduced. Very limited work has done on the diaphragms of micropump. Large numbers of mechanical micropumps have used plane diaphragms. The central deflection of diaphragm plays an important role in defining the micropump performance. The flow rate of mechanical type micropump strongly depends on the central deflection of diaphragm. In this paper compliant flexure diaphragms are designed for micropump to achieve higher deflection at lower operating voltage. Finite element analysis of compliant flexure diaphragm with single layer PVDF (Polyvinylidene fluoride) actuator is simulated in COMSOL. Compliant flexure diaphragms with a different number of flexures are analyzed. The central deflection of compliant flexure diaphragms is measured for driving voltages of 90V to 140V in 10 steps. The deflection of the compliant flexure diaphragm mainly depends on flexure width and length, the number of flexures in the diaphragm, PVDF thickness, diaphragm thickness and driving voltage. Use of compliant flexure diaphragm for micropump will reduce the mass and driving voltage of micropump. An attempt is made to compare the results of compliant flexure diaphragms with plane diaphragms. From the experimental results it is noticed that the compliant flexure diaphragm deflection is twice that of the plane diaphragm at same driving voltage. Deflection of three flexure and four flexure compliant diaphragms is 10.5µm and 11.5µm respectively at 140V.  

Image Processing To Aid in Graphene Detection

2014 ◽  
Vol 1702 ◽  
Author(s):  
Ryan D. Gorby ◽  
Lihong (Heidi) Jiao
Keyword(s):  
Image Processing ◽  
Single Layer ◽  
Optical Microscope ◽  
Single Layer Graphene ◽  
Camera System ◽  
Layer Graphene ◽  
Sophisticated Equipment ◽  
Processing Software ◽  
Image Processing Software ◽  
Few Layer Graphene

ABSTRACTQualitative techniques for the detection of graphene on a Si/SiO2 substrate, without the use of sophisticated equipment, are presented. Once calibrated, this technique can be used to detect Single Layer Graphene (SLG) and Few Layer Graphene (FLG) with the use of an inexpensive optical microscope (OM), OM camera system, and image processing software. This technique could be transferred to graphene deposited on other substrates or other 2-D materials with minor updates to mathematical theory.

THE EFFECT OF ALUMINUM ELECTROPOLISHING ON NANO-PORES ARRANGEMENT IN ANODIC ALUMINA MEMBRANES

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3267-3277 ◽  
Author(s):  
M. H. RAHIMI ◽  
S. H. TABAIAN ◽  
S. P. HOVEYDA MARASHI ◽  
M. AMIRI ◽  
M. M. DALALY ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Pure Aluminum ◽  
Optical Microscope ◽  
Anodic Alumina ◽  
The Other ◽  
Sem Images ◽  
Current Time ◽  
Nanoporous Anodic Alumina ◽  
Alumina Membranes ◽  
Stress Relieving

Surface conditions of aluminum can influence the final arrangement of nano-pores in fabrication of ordered nanoporous anodic alumina membranes (AAMs). This study is mainly focused on the different applied voltages of aluminum electropolishing by keeping all the other parameters constant. After heat treatment (stress relieving and annealing at 500°C) of pure aluminum sheets, the samples were electropolished at different voltages (10-60V) to obtain desirable surface smoothness, while the temperature of the container was kept constant. The current-time curves were recorded during electropolishing process. The surface roughness obtained in each applied voltage was examined using optical microscope and atomic force microscope (AFM). The process was followed by two-step anodization in order to reach ordered nano-pores. Finally, the influence of surface roughness on regularity of nano-pores was observed using scanning electron microscope (SEM). The SEM images were analyzed to investigate the morphology and the degree of self ordering of pores of the samples by using a new designed analytical method aiming MATLAB and fast Fourier transform (FFT) technique. It was concluded that the electropolishing voltage and the resulted surface roughness and also formed defects can competitively affect the arrangement of membrane's nano-pores. A desired smoothness obtained from electropolishing voltage of 30V. Also 40V provided the best order with respect to the other voltages.

Multilayer and Fiber Metal Laminate Materials Hydro-Bulging

2018 ◽  
Vol 941 ◽  
pp. 1996-2005
Author(s):  
Ehsan Sherkatghanad ◽  
Li Hui Lang ◽  
Shi Chen Liu
Keyword(s):  
Thickness Distribution ◽  
Single Layer ◽  
Experimental Tests ◽  
Middle Layer ◽  
Composite Fiber ◽  
Advanced Materials ◽  
Carbon Cloth ◽  
Stress Strain ◽  
Aluminum Composite ◽  
Fiber Metal

Advanced materials such as aluminum alloys and composites offer great potential for weight reduction applications in automotive and aerospace vehicles construction. In order to investigate the feasibility of using such materials in the form of laminates, sheet bulging with single-layer aluminum and the aluminum/Composite laminate with the carbon cloth as the middle layer is investigated under uniform liquid pressure conditions. The aluminum sheet stress-strain, wall thickness distribution, carbon fiber radius stress-strain distribution and the effect of die entrance radius etc. are discussed and compared in details. FE results validate that the numerical method can predict the same fracture regions for bulging-blank as observed in experimental tests. Furthermore, the study validates that multi-layer sheet hydro-bulging process with composite fiber as a middle layer is not feasible to form laminates due to rupture of composite fibers near edge regions. Further study is needed to improve the methodology.

FINITE ELEMENT ANALYSIS OF CONSTRAINED GROOVE PRESSING OF PURE ALUMINUM SHEETS

2013 ◽  
Vol 02 (01) ◽  
pp. 1350001 ◽  
Author(s):  
S. S. SATHEESH KUMAR ◽  
I. BALASUNDAR ◽  
T. RAGHU
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Strain ◽  
Deformation Behavior ◽  
Strain Distribution ◽  
Pure Aluminum ◽  
Detailed Examination ◽  
Deformation Characteristics ◽  
Element Analysis ◽  
Aluminum Sheets

Constrained groove pressing (CGP) is an attractive severe plastic deformation technique capable of processing ultrafine grained/nanostructured sheet materials. The deformation behavior of pure aluminum during constrained groove pressing is investigated by carrying out a two-dimensional finite element analysis (FEA). FEA predicted deformation behavior observed during each stages of pressing indicated almost negligible deformation in flat regions, whereas the inclined shear regions revealed diverse deformation characteristics. The plastic strain distributions unveiled inhomogeneous strain distribution at the end of one pass. Detailed examination of plastic strain evolution during CGP along various sections divulged superior strain distribution along middle surfaces when compared to top and bottom surfaces. The degree of strain homogeneity is evaluated quantitatively along different regions of the sheet and is correlated to the deformation characteristics. Load–stroke characteristics obtained during corrugating and flattening of sheets exhibited three stages and two stages behavior, respectively. The results obtained from the analysis are experimentally validated by processing pure aluminum sheets by CGP and the measured deformation homogeneity is benchmarked with FEA results.

Electromagnetic Performance due to Tooth-tip Design in Fractional-slot PM Brushless Machines

2015 ◽  
Vol 6 (4) ◽  
pp. 860
Author(s):  
Mohd Luqman Mohd Jamil ◽  
Zulfikri Zaki Zolkapli ◽  
Auzani Jidin ◽  
Raja Nor Firdaus Raja Othman ◽  
Tole Sutikno
Keyword(s):  
Double Layer ◽  
Great Influence ◽  
Single Layer ◽  
Torque Ripple ◽  
Element Analysis ◽  
Cogging Torque ◽  
Torque Density ◽  
Iron Modification ◽  
Winding Machine ◽  
Electromagnetic Performance

Permanent Magnet (PM) machines are favorable as an alternative to other machine topologies due to simpler construction and high torque density. However, it may result hight torque ripple due to an influence of cogging torque and electronic commutation. In this paper, comparisons of phase back-emf, static torque and cogging torque due to influence of tooth-tip asymmetry in 12-slot/10-pole double-layer and 12-slot/10-pole single layer winding machines are carried out using 2D Finite-Element Analysis. At rated condition, the stator asymmetry has great influence on the torque performance as there is significant reduction of torque ripple in 12-slot/10-pole mahine equipped with single layer winding than one equipped with double layer winding machine. It si confirmed that an optimum torque performance is desirable via stator iron modification in PM machines.

Experimental and finite element study on the single-layer reticulated composite joints

2020 ◽  
Vol 23 (10) ◽  
pp. 2174-2187
Author(s):  
Liang Zheng ◽  
Cheng Qin ◽  
Hong Guo ◽  
Dapeng Zhang ◽  
Mingtan Zhou ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Wall Thickness ◽  
Great Influence ◽  
Single Layer ◽  
Experimental Results ◽  
Steel Pipe ◽  
Cover Plate ◽  
Element Analysis

In this article, a new type of reticulated joint, named the steel–concrete composite reticulated shell joint, is proposed. The proposed reticulated shell joint consists of an inner circular steel pipe, an outer circular steel pipe, a steel cover plate, and internal concrete. Five test specimens were tested under axial compression. The variable study included the wall thickness of the inner and outer circular steel pipes and the radius of the inner circular steel pipe. The test specimens exhibited a high bearing capacity and good plastic deformation ability under axial compression. The test results show that the wall thickness of the outer circular steel pipe and the radius of the inner circular steel pipe have a great influence on the bearing capacity of the steel–concrete composite reticulated shell joint, while the wall thickness of the inner circular steel pipe has little influence on the bearing capacity of the steel–concrete composite reticulated shell joint. Based on the test of the steel–concrete composite reticulated shell joints under axial load, the three-dimensional nonlinear finite element model was used to analyze the mechanical properties of the steel–concrete composite reticulated shell joints under axial compression. The results of the finite element analysis showed good agreement with the experimental results. The formula for calculating the bearing capacity of the joint is derived. By comparing with the experimental results, the calculated results are basically consistent with the experimental results.

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