bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Mechanism of the Displacement Error of Reverse Positioning and Clamping for Rotary Table
Authors: Jiang Xiao Geng , Liu Bei Ying , Yang Hui
Published: September 2011

Reverse positioning is a significant positioning method of rotary table, the positioning displacement error caused by clamping cannot be neglected. Since the direct acting factors are numerous, the mechanism and value of the displacement error are difficult to test. In this paper, we took the general rotary table as the experiment object, designed and manufactured a set of device that could analyze the reverse positioning. According to various measurement conditions, first the stress-strain of all the components was calculated based on the finite element analysis. Then the displacement errors were measured on the experimental device. Finally the comparison between the simulation and the experiment results allowed the improvement of the model, algorithm analysis and the structure of the experimental device. As the theoretical results continued to get close to the measured values, on the basis of the process above can we conclude the influencing factors and the possibility to reduce the error, thus develop a new approach for the reduction of the reverse positioning error.
Research on the Parameter Measurement Methods of Digital Channelized Reconnaissance Receiver
Authors: Jiang Hai Qing , Gao Mei Guo , Sun Guo Hong , Tang Pu Zhao
Published: September 2011

The pulse description word (PDW) measurement method of digital channelized reconnaissance receiver was investigated. The parameter measurement flow of digital channelized reconnaissance receiver was introduced. The measurement methods of the instantaneous amplitude, the instantaneous frequency, the pulse width of wideband frequency modulated signal and the direction of arrival (DOA) were discussed in detail, which have been applied to reconnaissance receiver in ESM system successfully.
Tolerance Optimization Design Based on Physical Programming Methods and PSO Algorithm
Authors: Qiu H.B. , Dong Y. Y. , Wang Y. , Gao L.
Published: September 2011

Product tolerance is one of the key factors which can determine the good or bad performance of mechanical products. Its size not only affects the manufacturing and assembly process, but also affects product features [1]. Thus tolerance optimization design gets more and more attention. In this paper, an improved physical programming method is used to make mathematical modeling for tolerance allocation problem of assembly dimensional chain, and PSO algorithm is also used to improve solving ability. And the effective solution for tolerance optimization is designed.
Error Analysis of Absolute Interferometric Testing Based on Reconstruction of Rotational Shear
Authors: Jia Xin , Xing Ting Wen
Published: September 2011

Recently most of modern absolute measurement rotation the flats or spheres in the interferometer. We review traditional absolute testing of flats methods and emphasize the method of reconstruction of rotational shear. The rotation of the lens can lead to some errors such as angle rotation error, center excursion error and other coordinate system motion error. 36 Zernike polynomials are used to generate 3 flats and Matlab are used to simulate the arithmetic. There have some phase problems on FFT arithmetic in Matlab which can cause some errors. Results are shown about how these errors influence the accuracy. The analysis results can also be used in other interferometer systems which have the motion of the coordinate system.
Experimental Modal Analysis of Car's Body-in-White
Authors: Li He , Fu Shi Bo , Wen Bang Chun
Published: September 2011

To reduce noise and make the structure of the car more rational, we established modal test system of car's body-in-white in this paper. Car body-in-white was mounted on rigid platform with four coil springs. The car was excited by an electromagnetic exciter. The method of single-point excitation and multi-point collecting vibration was used in this test. Excitation point was chosen in the bearing beam. Signals picked up by the acceleration sensors were processed in the software of Mescope. With this system, different modal frequencies and modal characteristics of the car are acquired. The results show that modal parameters are effective and reliable and those parameters can be basis for the designer to improve the structure of the car.
Error Sensing Strategy for Active Structural Acoustic Control Based on Acoustic Radiation Modes
Authors: Wu Jin Wu , Tan Fei
Published: September 2011

A new sensing strategy based on acoustic radiation modes for active structural acoustic control approach is proposed for the minimization of the acoustic radiation from a vibrating simply supported plate. Measuring a few points velocity on the vibrating surface and solving the underdetermined equations of the radiation mode expansion, the approximate values of amplitudes of the first radiation modes can be obtained. Taking the above approximate amplitudes as the input signals of the controller, this forms an error sensing strategy based on radiation modes and corresponding active control strategy. The numerical simulations results are presented to show the feasibility of this error sensing strategy.
Gyro Drift Calibration Method Based on Free Double-Position Ground Self-Alignment for SIMS
Authors: Li Jian Li , Fang Jian Cheng , Zhong Mai Ying , Liu Bai Qi
Published: September 2011

The gyro drift is a crucial factor for initial orientation error and measurement error of SIMS (Strapdown Inertial Measurement System). Accurate ground calibration of gyro drift is an important way to reduce errors of alignment and inertial measurement. Based on the initial alignment principle of SIMS on stationary base and inertial navigation algorithm, the gyro drift models are established. A new method that a gyro drift calibration method based on free double-position ground self-alignment is proposed. The simulation and experiment results show that the method can calibrate and compensate the gyro drift, improve the measurement precision of SIMS, and verify the efficiency of the proposed method.
Research on the Performance Detecting System of High-Precision Small-Scale Solid Rocket Motor
Authors: Cao Qi , Feng Xi Ping , Li Jie , Dong Tao
Published: September 2011

According to the performance detecting requirements in development and manufacture of solid rocket motor, a test platform had been set up based on flexible test fixture, a measurement & control platform had been built using virtual instrument technology, a set of solid rocket motor ground test performance detecting software including parameter calibration module, data measurement module and data processing module had been developed based on the LabVIEW7.1, and the solid rocket motor performance detecting system was constructed. The application results through testing normative solid rocket motor show that: the system could actualize parameter calibration expediently, experimental data collection and processing rapidly, even reach the measurement precision by 0.3% that required in project and could monitor the working process of solid rocket motor simultaneously, which satisfies high-precision requirement of motor performance detecting.
Irreducible Water Saturation Measurement of Volcanic Rocks Using Nuclear Magnetic Resonance
Authors: Zhou Yu , Guo He Kun , Wei Guo Qi
Published: September 2011

Irreducible water saturation is one of the fundamental parameters in characterizing reservoir formations, and determined as the key factor in reserve calculation and fluid type identification. Measurement on whole core must be taken to analyze irreducible water saturation of volcanic rocks as a result of lithological diversity, porous structure complexity and strong heterogeneity. A new testing method for whole core is proposed by combining Nuclear Magnetic Resonance and centrifugal tests. This new method measures irreducible water saturation using T2 spectrum of whole core demarcated by T2 cutoff measured on 25mm or 38mm diameter core samples which drilled from the whole core. The new method solved the size and shape restricts, long test cycles and viscous fingering defects of conventional methods. According to the comparison with conventional method, the results of the new method coincide well on homogeneous rocks, and are more accuracy with fractured samples.
Ultraviolet Spectroscopy Method for Classifying Vinegars
Authors: Xie Hua Dong , Bu Li Jun , Peng Xiang Wei , Li Zhi Xi
Published: September 2011

An inexpensive and simple approach using ultraviolet-spectroscopy to distinguish vinegar samples was developed. Vinegar samples were diluted with distilled water(water/vinegar was 6/1, v/v), then distilled with rotary evaporator at 45°C. The distilled liquid was introduced into the UV-Vis 2550 spectrophotometer to scan the UV spectrum from 245 nm to 330 nm, distilled water was used as reference solution. Once spectra were collected, principal components analysis (PCA) and artificial neural network (ANN) were employed for the exploratory analysis and the development of classification models, respectively. The criteria for discrimination were various raw materials and the different fermentation process of vinegars. The correct rate of the classification according to the production process was more than 90% and it was 100% according to the raw materials. The ANN model also could be used to class vinegar samples according to the raw materials, the correct rate was 80.95% in this research.
Research on Complex Product Lifecycle Quality Management Technology Based on 3D Product Model
Authors: Jia Xiao Liang
Published: September 2011

In connection with characteristics of complex product development, in order to solve problems of long product development cycle, multi-collaborative firms, difficult to control product quality in manufacturing firms, the approach of complex product lifecycle quality management technology based on the collaboration of 3D virtual product and physical product is put forward. The connotation of complex product lifecycle quality management technology based on 3D product model is analyzed. Complex product lifecycle quality management model based on 3D product model is founded also. Base on 3D virtual product model and PLM technology, key technologies on complex product lifecycle quality management are described in detail.
Influence of Design of Hydraulic Components on their Operation in Low Ambient Temperatures
Authors: Jasiński Ryszard
Published: September 2011

In many machines and devices there are hydraulic drives. They should operate well in various weather conditions, also in low ambient temperatures. Some malfunctions may occur during operation of hydraulic system in a so called “thermal shock condition”, which happens when frozen hydraulic component (e.g. hydraulic pump, motor or directional spool valve) is suddenly supplied with hot oil. Transient thermal state emerges in these conditions. Particular elements of component warm up differently. This results in different thermal expansion of components during warm up, which is changing the size of clearance between cooperating elements. Experimental tests of hydraulic components in low ambient temperatures were conducted in the hydraulic laboratory of the Faculty of Mechanical Engineering of Gdansk University of Technology. They concerned: orbital motors, satellite motors, gear pumps, spool valves (also proportional), piston pumps, and hydraulic cylinders. It was proved, that in thermal shock conditions some malfunctions may occur, especially with large temperature differences between oil and component. Based on results of the tests of hydraulic components and systems start-up in low ambient temperatures, one can perform a change in components design, change the type of material of components elements, and even prepare a proper procedure to be followed during start-up of cold hydraulic components and systems. In the article discusses some designs of hydraulic components resistant to thermal shock, and how to prepare components to work in low temperatures, e.g. by providing system with an additional heater to ensure uniform heating of elements in components. Change in design of hydraulic components resistant to thermal shock conditions can be obtained through computer simulation method. Analytic and computer simulation methods can be used by engineers who design machines and devices that work in low ambient temperatures.
An Analysis of Weld Damage in Punching Press
Authors: Ryś Jan , Łaczek Stanisław
Published: September 2011

This article deals with a description of weld damage in a punching press. Static and modal analyses were performed in ANSYS v.11. Dynamic stresses in welds were evaluated using the Laplace’s transformation for a simplified model with a single mass on a spring.
Novel Design of an Ocean Wave Power Device
Authors: Dymarski Czesław , Dymarski Paweł , Litwin Wojciech
Published: September 2011

The paper presents a novel device for capturing the energy of sea-waves and the construction of its model for conducting test in a towing-tank. The paper also presents the research program and general analyses on selecting the hull form and systems of anchoring and propulsion. In addition, it includes remarks and observations gathered following initial tests and measurements of the device operating in regular wave conditions.
Numerical Analysis of Crack Propagation in Silicon Nitride
Authors: Karaszewski Waldemar
Published: September 2011

The properties of ceramics, specifically low density, high hardness, high temperature capability and low coefficient of thermal expansion are of most interest to rolling element manufacturers. The influence of ring crack size on rolling contact fatigue failure has been studied using numerical fracture analysis. Such cracks are very often found on ceramic bearing balls and decrease fatigue life rapidly. The numerical calculation are based on a three dimensional model for the ring crack propagation. The stress intensity factors along crack front are analyzed using a three-dimensional boundary element model. The numerical analysis is verified by experimental studies.
Selected Properties of Bearings with Helical Groove on the Journal
Authors: Sep Jarosław
Published: September 2011

The paper presents results of tests concerning slide bearing with helical groove on the journal selected properties. It has been stated that during lubrication with contaminated oil helical groove results in wear decrease. On the other hand while lubricating agent was clean oil helical groove results in load carrying capacity decrease and oil flow rate increase. The proposition of non-dimensional index describing the groove and helical line is also presented in the paper. This index is correlated with bearing characteristics and its wear
The Influence of Gas Mixture in the Glow-Discharge Nitriding Process of Austenitic Stainless Steel on Characteristic of Nitrided Cases
Authors: Sitko Artur , Szkodo Marek , Gazda Maria
Published: September 2011

This paper presents investigations of nitrided cases after the glow-discharge nitriding process. The nitrided cases were obtained by using a different chemical composition of gas mixture at the temperature of 450OC. The glow-discharge nitriding process was carried out on austenitic stainless steel, grade of steel X5CrNi18-10. The chemical composition and phase identification of the nitrided cases were examined by using the glow-discharge optical emission spectrometry (GD-OES) and X-ray diffractometry (XRD)
The Integrity Analysis of the Structural Element Made of Ultra High Strength Steel
Authors: Graba Marcin , Nykänen Timo , Neimitz Andrzej
Published: September 2011

In this paper, a FITNET analysis of the structural element made of ultra high strength steel was performed. The critical loadings at failure were estimated at three levels of analysis and two temperatures, -40°C and +20°C. The results of the analysis were verified by full scale experiments at -40°C, which proved that the predictions of the critical moment provide a sufficient safety margin.
Designing a Pumping System of Gear Pumps Featuring the Involute Internal Gearing
Authors: Słodczyk Damian , Stryczek Jarosław
Published: September 2011

On the basis of the analysed references it has been shown that an important problem in designing hydraulic machines is to develop a method of designing a pumping system of pumps with the internal gearing, which would integrate designing gears and compenstion elements. The authors of the paper has defined a design algorithm that consists of three basic stages: designing a concept of the system, designing the gear subsystem, and designing the compensation subsystem. The design process at particular stages have been described, and the results have been presented in engineering drawings. An original computer program 'Internal Pumping Set' which enhances the process of designing the pumping system has been created. An application of the program has been presented, and a design of an exemplary pumping system made.
Development of Bevel Gear Motion Transmission Graphs with FEM
Authors: Pacana Jacek
Published: September 2011

The article presents the course of the calculations and conclusions from the analysis of a bevel gear motion transmission using FEM. The motion transmission graphs show the angular variation of the driven gear in the case of a driving pinion that rotates with a constant angular velocity. In contrary to the classical Tooth Contact Analysis, which is carried out on stiff bodies, FEM analysis includes deformations of mating gears. Thus, it brings more realistic information on dynamic behavior and noise characteristic of analyzed gear drive.
Experimental Investigation of Prototype Water-Lubricated Compliant Foil Bearings
Authors: Olszewski Artur , Wodtke Michał , Hryniewicz Piotr
Published: September 2011

First gas-lubricated compliant foil bearings (CFBs) were built in the 1950s. Due to their significant advantages, such as oil-free operation, good tolerance to bearing misalignment and very low maintenance, they have been penetrating the bearing applications for high speed compressors, air-cycle machines and gas turbines. The work presented here investigates a novel idea of water-lubricated compliant foil bearings, which could be used in applications where environmentally friendly lubrication is desired, for example in hydroelectric turbines or water pumps. Experimental results collected for three prototype water-lubricated foil journal bearings are presented. The tests were conducted under steady radial load and with the sliding speed varied incrementally. A sequence of design improvements is presented, with the best bearing demonstrating friction coefficient of about 0.01 at the sliding speed of about 4 m/s and the radial load of about 300 kPa. Encountered difficulties, research methodology and the testing equipment are also described.
High Strength Aluminium Alloys Extrusions - A Review of the Thermo-Mechanical-Process in High Performance Profile Manufacturing
Authors: Jensrud Ola
Published: September 2011

High strength aluminium alloys extrusions have successfully been applied for years in transportation industry. High strength alloys are normally understood to be alloys based on the Al-Mg-Zn system (7xxx) with addition of Cu in some cases and of course some micro structural controlling elements as Cr or Zr. The level of strength in the hardened condition (T6) is typical in the range from 320 to 500 MPa. The combination of strength and ductility of extrusions from the 7xxx series alloy gives several advantages in light weight construction and can contribute to lighter body and chassis in automotive. Significant improvements in extrusion speed are realized when the ratio Zn/Mg is increasing this means that alloys with high Zn and low Mg like 7108 and 7003 are favourable. Zr is the most promising element with respect to control the recrystallization phenomena. The fully understanding chemistry and the thermo-mechanical process route in profile based components manufacturing is concluded to be fundamental for high performance products.
Numerical Modeling of Extrusion Welding in Magnesium Alloys
Authors: Xu Yan , Misiolek Wojciech Z.
Published: September 2011

Solid-state welding takes place during the extrusion of hollow shapes and tubes made from selected metals such as aluminum and magnesium and their alloys. DEFORMTM is one of the most frequently used FEM software packages to analyze the metal flow in deformation processes. However, it has some limitations while applied to study the extrusion welding. The 2D and 3D versions of DEFORMTM cannot determine if extrusion welding takes place in a port-hole die. This limitation is a result of a lack of ability to transfer the localized deformation conditions to a judgment about a good or poor weld. In this work, a new modeling method has been proposed to obtain the localized information at the extrusion welding seam. A so-called pressure plate was virtually inserted in the position of the extrusion welding seam, which plays a role of a sensor and has recorded all the information at the given seam during the entire extrusion process. Analytical methods have been utilized to study the data collected from this sensor to evaluate the probability of the formation of the sound extrusion welding seam. The generated results have been used to verify Plata & Piwnik extrusion welding criterion and can be implemented into existing extrusion models to achieve better prediction of weld integrity.
Optimization of Aluminium Extrusion by Porthole Die Using a down Scaled Equipment
Authors: Gagliardi Francesco , Ambrogio Giuseppina , Filice Luigino
Published: September 2011

Porthole die extrusion has been always more used for the production of hollow profiles. The process is characterized by a complex die whose design is important for the product soundness. The quality of the welding line and, consequently, the quality of the extruded parts strictly depends on the extrusion optimization; for this reason, the influences that, each process parameter has on the pressure along the welding plane, have to be correctly understood. Unfortunately, the complexity of the die geometry generates great research difficulties if different parameters are analyzed; furthermore, even 3D numerical investigations present relevant drawbacks due to the high computational time and the results quality. In this work, a simplified and flexible porthole die is proposed; the equipment was designed and manufactured rectifying a quarter of a traditional porthole die. Moreover, the extruded part has flat shape with welding line in the middle; by doing that, its quality can be simply analyzed through standard tensile tests. Different geometrical variables were investigated, i.e., the bridge shape and width and the bearing length; their interactions on the process dynamics and on the product quality were also discussed. The Analysis of Variance (ANOVA) technique was used to evaluate the obtained results.
Coupled Simulative-Experimental Procedure for Studying the Solid State Bonding Phenomena
Authors: D'Urso Gianluca Danilo , Longo Michela , Ceretti Elisabetta , Giardini Claudio
Published: September 2011

In extrusion operations, material solid state welding takes place thanks to the very high pressure and temperature at which the material undergoes between the several welding criteria developed, the attention was particularly focused on the Piwnik and Plata one. In this criterion a suitable parameter w, calculated as the interface pressure and the effective stress ratio integrated along the time, has been defined. According to this criterion the material should start to weld as this parameter exceed a limit value wlim. In the present paper a new procedure for the wlim identification as function of the temperature, based on coupled experimental-simulative strategy, is proposed. In particular, flat rolling experimental tests of sandwiches made of two rectangular specimens in AA6082 alloy were performed. The specimens were characterized by different heights in order to consider different compression ratio, that means different interface pressure and effective stress distributions. All the tests were repeated at different temperature. Once the experimental tests were performed, FEM simulations of the rolling process were run for the very same conditions. Thanks to a suitable user routine developed and implemented in the calculus code, it was possible to evaluate the steady state value of the w parameter for all the different conditions at the steady state conditions. By verifying if the actual experimental test demonstrated the presence or less of material bonding, it was possible to identify the wlim values as function of the temperature. Particular attention must be paid to the study of the macrostructure of the welded material in order to identify the influence of the process parameter on the weld quality. This means that it is possible to identify not only if the weld will take place, but also if it will be qualitatively adequate.
Effect of Liquid Nitrogen Die Cooling on Extrusion Process Conditions
Authors: Donati Lorenzo , Segatori Antonio , Reggiani Barbara , Tomesani Luca , Bevilacqua Fazzini Pietro Alfredo
Published: September 2011

In the paper, a die for the production of a complex hollow profile made by AA6060 alloy on an industrial 2500 ton press has been manufactured and tested under strict monitored conditions. In particular 5 thermocouples were placed in proximity of interesting positions inside the die: 3 next to the bearings and two near the welding chambers. A self-calibrated pyrometer was used for the temperature monitoring of profile. Press loads, ram speeds and container temperatures were continuously recorded directly from the press system. Six billets were initially extruded in order to reach a steady state condition being the last three used as industrial benchmark for the 2011 edition of the ICEB conference. Then the nitrogen was completely and partially opened and the evolution of the temperature in the die and in the profile recorded together with the process load. The effect on bearing temperature was extreme, in particular in proximity of nitrogen inlet, while almost no change in welding chamber thermocouples and in the process load was revealed.
New Concepts for Cooling of Extrusion Dies Manufactured by Rapid Tooling
Authors: Hölker Ramona , Jäger Andreas , Ben Khalifa Nooman , Tekkaya A. Erman
Published: September 2011

To prevent local overheating of the workpiece material in hot aluminum extrusion the influence of die cooling was investigated. Numerical simulations of extrusion revealed an advantage of the die bearing cooling, which can be accomplished by locating the cooling channels close to the die/bearing surface. Since the fabrication of especially geometric complex cooling channels located near the die surface is not possible by conventional manufacturing technologies, the technology of rapid tooling was introduced into hot aluminum extrusion and experimentally tested. Cooling channels near to the bearings show promising results allowing extensions of extrusion limits, especially the extrusion speed and therefore productivity.
Influence of Contact Friction Conditions on Thin Profile Simulation Accuracy in Extrusion
Authors: Stebunov Sergey , Biba Nikolay , Lishnij Andrey
Published: September 2011

The paper presents the development of the Finite Element model for simulation of thin aluminium profile extrusion of both solid and hollow shapes. The analysis has shown that the material flow in simulation is very dependent on the friction model. Experimental and theoretical studies show that friction traction on the interface between the tool and the deformed material can be represented as a combination of adhesive friction force and the force that is required to deform surface asperities. In aluminium extrusion we can clearly distinguish two different areas with respect to friction conditions such as sticking and sliding and transient zones between them. The lengths of these zones are also dependent on variation of the choke angle and actual thickness of the profile. To get these values the material flow problem is to be coupled with the simulation of the tools deformation. A series of experiments with specially designed tools have been done to investigate how the bearing length and choke angle may influence the extension of different friction zones and by these means vary the material flow pattern. The friction models have also been tested with industrial profiles of complex shapes and have shown good correspondence to reality.
Constitutive Equations for Hot Extrusion of AA6005A, AA6063 and AA7020 Alloys
Authors: Pinter Tommaso , El Mehtedi Mohamad
Published: September 2011

Constitutive equations relate thermo-mechanical parameters, i.e. strain (ε), strain rate (έ) and temperature (T), with flow stress (σ). The most popular constitutive relationship, among those used in the study of hot deformation, is the phenomenological sinh Garofalo equation. In recent years several papers described the hot deformation of aluminum alloys by mean of hot torsion testing. However, sinh constitutive parameters are seldomly available in literature even for the commonest aluminum alloys used today by the extrusion industry. This paper presents the result of the torsion tests providing constitutive equations for AA6005A, AA6063 and AA7020 alloys. The relative extrudabilities of these alloys were estimated by means of FEM simulation carried out by the HyperXtrude® software.
Co-Extrusion of Aluminium-Titanium-Compounds
Authors: Grittner N. , Striewe B. , von Hehl Axel , Bormann D. , Hunkel M. , Zoch H.W. , Bach F.W.
Published: September 2011

The combination of different metallic materials enables the design of lightweight structures with tailor-made properties at global as well local scale and offers great potential for advanced solutions especially for the aircraft and automobile sector. Whereas titanium alloys show particular high mechanical strength and good corrosion resistance, aluminium alloys provide a considerable lower density and consequently higher potential for weight savings. However, after conventional fusion joining, e.g. after laser beam welding, heat affected zones, porosity or grain growth may occur and impair the local properties [1, 2]. In contrast, by solid-state joining techniques like co-extrusion these disadvantages can be avoided. Therefore co-extrusion exhibits an attractive solution for long products combining aluminium and titanium based alloys. Current investigations have been focused on the co-extrusion of aluminium and titanium, where titanium is the reinforcing element that is inserted in aluminium profiles. Two different billet variants were examined in the investigations, a titanium-core integrally moulded in the aluminium-billet and titanium-core inserted in a hollow drilled aluminium-billet. Experiments were made with different material combinations, Al99.5 with titanium grade 2 and AlSi1MgMn with Ti6Al4V. Beside mechanical properties of compound the formation of bonding zone are presented.
Experimental and Numerical Analysis of Material Flow in Porthole Die Extrusion
Authors: Kloppenborg Thomas , Schwane M. , Ben Khalifa Nooman , Tekkaya A. Erman , Brosius Alexander
Published: September 2011

The design of porthole dies for aluminum extrusion processes is very complex. For the accurate design, fundamental knowledge about material flow is of major importance. To gain these information, numerical methods are increasingly utilized. The accuracy of the simulation results depends mainly on the precision of the used boundary conditions in the model. Therefore, visioplastic analyses of the material flow inside a porthole die are presented in this paper. A special modular tool concept was developed to prepare and visualize the material flow inside the process. The results of the experimental analysis were used for the verification of numerical results which were calculated with the commercial software codes Deform3D and HyperXtrude.
Lateral Confinement and Ballistic Performance of TiC-TiB2 Composites
Authors: Zhao Zhong Min , Zhang Long , Song Yi Gang , Huang Xue Gang
Published: September 2011

Based on using combustion synthesis under high gravity to prepare TiC-TiB2 composite, the ceramic armour targets were achieved by the heat-shrunk lateral, cover and back confinements of steel sleeves and plates. Ballistic testing showed that under the impact of long-rod tungsten alloy projectile, the low-carbon-steel sleeve failed to laterally confine the ceramic due to its inadequate residual strength, resulting in poor ballistic performance of the ceramic, whereas the medium-carbon-steel sleeve had a sufficient residual strength to support lateral confinement of the ceramic as the long-rod tungsten alloy projectile makes room in the ceramic for its penetration, the confined ceramic could present its real ballistic performance, and the results of ballistic testing promised lateral confinement and cover confinement of high-strength metal would be beneficial to the improvement in ballistic performance of ceramic armour.
Fracture Behavior of SiC-TiB2 Composite Measured by Different Test Methods
Authors: Jiang Liang , Chen Yu Hong , Chen Bin , Sun Wen Zhou
Published: September 2011

SiC-TiB2composite was prepared by boron (B) and carbon(C) as sintering additive via presureless sintering in 2180°C. Fracture toughness of SiC-TiB2measured by indentation method and single edge notched beam specimen tenichques were analyzed and compared, and the most suitable indentation method equation was confirmed. Results revealed that the fracture toughness and flexure strength of the materials were influenced at varied degree by the content of TiB2, which had no effect on the selection of the most suitable equation for calculating the fracture toughness of the materials by indentation method. The fracture toughness decreases with the increasing TiB2content. When the TiB2content was 30%, SiC-TiB2composite had the best fracture toughness.
Structure and Characteristics of Spherical-Pore Silicon Carbide
Authors: Li Qiang , Zheng You Jun , Xia Jin Feng , Jiang Dan Yu , Wu Hao , Wang Chang Lian
Published: September 2011

Sintered Silicon Carbide material with fine grain structure shows excellent wear resistance, highly chemically resistance, excellent performance in a wide range of applications. This material can improve upon the exceptional corrosion and erosion resisting properties through the addition of unique micro pores. A designed spherical-pore Silicon Carbide material was obtained after pressureless sintering. The photomicrograph shows a typical appearance of unique micro pore. SEM was also employed to investigate the micro-structure of as-prepared SiC material. The properties of micro-pore Silicon Carbide, such as density, hardness, strength, etc. were determined in detail. The relationship between the spherical-pore structure and properties of Silicon Carbide were discussed.
Test Method and Equipment for Electrically Conducting Property of Ceramic/Carbon Composites
Authors: Liu Kai Qi , Wang Shou Zeng , Ding Yu , Liu Yong Feng
Published: September 2011

Ceramics/carbon composites have been used widely, Such as, the magnesia/carbon refractory was used in some DC electric arc furnaces as anode, because of its high temperature performance and electrical conduction. The ceramic/carbon composite was easily oxidized in high-temperature at atmosphere with oxide, so the test of high-temperature electrically conducting properties needs protection. This paper proposed a test method and equipment for specific resistance both in room and high temperature, according to the electrically conducting property of ceramics/carbon composite. And the specific resistance of magnesia/carbon composites (C content <20%) was tested by this equipment. It is showed that, as the carbon content growing, there is a threshold at which the specific resistance falls sharply. Moreover, as the heating temperature increasing, the composites’ specific resistance shows a “gradual- sudden- slow- comparatively steady” changing process. The minimal specific resistance level of the developed ceramics/carbon composite (C content<20%) is about 10-5Ω·m.
Assessment on the Electrical Conductivity of Additive Fillers into Carbon Fiber-Cement Based Composites
Authors: Qin Jun Jie , Yao Wu , Zuo Jun Qing , Cao Hai Yong
Published: September 2011

This paper gives an assessment on the electrical conductivity of different additive fillers (graphite, multi-walled carbon nanotubes) into carbon fiber-cement based composites (CFRC). Results show that cement matrix containing 0.4% carbon fiber (CF) and 0.5% multi-walled carbon nanotubes (MWCNTs) exhibits an excellent electrical conductivity of 33.65Ω·cm. When the content of CF is below the percolation threshold (0.4% CF), adding graphite is beneficial to the electrical conduction of CFRC, which has a tremendous drift from 3991.44Ω·cm to 524.33Ω·cm as the content of graphite varies from 0% to 30%. However, when the content of CF is above the percolation threshold, adding graphite makes no advantages in the electrical conductivity of CFRC because of leading to a porosity rising. MWCNTs are useful conductive constituents for CFRC and can increase electrical conductivity by two orders of magnitude. However, excessive adding MWCNTs into CFRC will have a rapid increase of electrical resistivity on the contrary.
Preparation and Characterization of Lead-Free Piezoelectric Ceramics
Authors: Chen Qiang , Li Jin Xu , Zhang Li Hui , Bai Yang , Su Yan Jing , Qiao Li Jie , Volinsky Alex A.
Published: September 2011

(K,Na)NbO3-based piezoelectric ceramics are promising candidates for practical applications of lead-free piezoelectric materials due to their excellent piezoelectric properties. In this paper, lead-free piezoelectric ceramics (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3(KNL-NTS)were successfully fabricated by traditional ceramics processing. The effects of sintering temperature on the structure, density and electrical properties of KNL-NTS ceramics were investigated. Crystal phases of both calcined powders and KNL-NTS ceramics have orthorhombic structure similar to that of KNbO3 ceramics. The piezoelectric coefficient first increases and then decreases with sintering temperature in the 1100-1180 °C range. KNL-NTS ceramics sintered at 1160 °C shows the maximum piezoelectric coefficient of about 199 pC·N-1and the maximum remnant polarization of 18.75 μC·cm-2, with the corresponding 10.95 kV·cm-1coercive field and 4.74 g/cm3density.
Dielectric and Piezoelectric Properties of Lead Free (1-x-y)Na1/2Bi1/2TiO3-xBaTiO3-yBiFeO3 Piezoelectric Ceramics
Authors: Wang Yue Fang , Yi Xiu Jie , Pan Wei , Zang Guo Zhong , Du Juan
Published: September 2011

Lead-free (1-x-y)Na1/2Bi1/2TiO3-xBaTiO3-yBiFeO3 ceramics were synthesized by ordinary sintering technique. The compositional dependence of phase structure and electrical properties of the ceramics was systematically investigated. All samples possessed pure perovskite structure. The dielectric and piezoelectric properties of ceramics were investigated with the amount of different BiFeO3 substitutions. The addition of BiFeO3 can not only decrease Ec and Pr but also lead to a significant degradation of the dielectric loss tanδ.
Electrical Characterization and Microstructures of Ce-Doped Bi4Ti3O12 Thin Films
Authors: Liu J. , Chen M. , Mei X.A. , Sun Y.H. , Huang Chong Qing
Published: September 2011

Tb-doped bismuth titanate (Bi4-xCexTi3O12: BCT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Ce-doping into BIT caused a large shift of the Curie temperature (TC) from 675°C to lower temperature and a improvement in dielectric property. The experimental results indicated that Ce doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BCT film with x = 0.75 were 23 μC/cm2 and 80 kV/cm, respectively.
Ferroelectric Properties and Microstructures of Dy2O3-Doped Bi4Ti3O12 Ceramics
Authors: Liu J. , Chen M. , Mei X.A. , Sun Y.H. , Huang Chong Qing
Published: September 2011

The electrical properties of Dy-doped bismuth titanate, Bi4-xDyxTi3O12(BDT) ceramics prepared by a conventional electroceramic technique have been investigated. XRD analyses revealed Bi-layered perovskite structure in all samples, and indicted that Bi ions were only substituted near the Ti-O octahedron layers by Dy ions. SEM micrographs show randomly oriented and plate-like morphology. The remanent polarization (Pr) and coercive field (Ec) of the BDT ceramic with x = 0.75 were above 19μC/cm2and 50KV/cm, respectively. The large value of remanent polarization and low coercive field of Dy-doped bismuth titanate ceramics promote these materials to potential applications.
Measurements of Thermoelectric Behavior and Microstructure of Carbon Nanotubes/Carbon Fiber-Cement Based Composite
Authors: Zuo Jun Qing , Yao Wu , Qin Jun Jie , Cao Hai Yong
Published: September 2011

Thermoelectric behavior and microstructure of carbon nanotubes/carbon fiber(CNTs/CF)- cement based composite have been measured in this study. An self-made experimental setup was applied to test the thermoelectric power (TEP) of the composites. The results show that the higher the CNTs content, the less positive the absolute thermoelectric power is. When CNTs addition incresed to 1.0% by weight of cement, the absolute thermoelectric power changed sign from positive to negative. Scanning electron microscopy (SEM) was used to characterize the morphology of CNTs, CF and the structure of Portland cement-CNTs-CF systems. SEM analysis of the results show that good interfacial adhesion between CNTs and cement matrix is seen with CNTs tightly wrapped by Calcium-Silicate-Hydrate (C-S-H). With the incorporation of CNTs/CF in cement based composite, the cement-CNTs-CF system exhibits a porous microstructure.
Experimental Study on Magnetic Fluids Viscous Damper
Authors: Zhang Zhi Li , Li De Cai , Huang Li Ming , Han Qi , Shi Dan
Published: September 2011

Magnetic fluids viscous damper is a new type of dampers, whose structure including magnetic fluids, permanent magnet and a non-magnetic container. Inside the non-magnetic container, magnetic fluids supports the permanent magnet to suspense in it and moves as a working element. Under the influence of external oscillatory inertia forces, the movement of the permanent magnet leads the damper to a viscous dissipation of the oscillating system energy. This kind of viscous damper is very suitable for spacecraft under low frequency oscillation. In our experiments, model of magnetic fluids viscous damper and its test circuit were designed. The result of tests indicates that the damper based on magnetic fluids can suppress the low frequency oscillation.
Experimental Study of Surface Tension Coefficient for Magnetic Fluid
Authors: Wang Qing Lei , Li De Cai , Wang Fan
Published: September 2011

The author measured surface tension coefficient for liquid with a new experimental apparatus, measured magnetic fluid surface tension coefficient at different temperatures and with different volume of surfactant. By the analysis of experimental data, we obtained that magnetic fluid surface tension coefficient decreases with the increasing temperature and increases with the addition of surfactant volume and reaches a certain stability value. We also obtained the expression of magnetic fluid surface tension coefficient and the temperature or surfactant. This paper discussed the relationship between the liquid surface tension coefficient and the temperature and surfactant from the view of thermodynamics.
Experimental Study of Large Gap Magnetic Fluid Static Sealing
Authors: Xing Fei Fei , Li De Cai , Yang Xiao Long
Published: September 2011

A large gap structure device of the magnetic fluid static sealing have been designed, and this structure was made to test the anti-pressure, the experimental station and process was discussed, the factors that affect the experiment result were also been analyzed. The pressure capacity and the size of the leak rate have been measured when the sealing gap were 0.4mm, 0.5mm, 0.6mm and 0.7mm respectively. Experiments show that the design of the sealing structure can solve the problem of large gaps in the magnetic sealing, and for the gap of 0.4mm, its anti-pressure capacity is 70 percent more than the pressure of the typical sealing gap (0.15mm).
Luminescence Properties of Eu2+ Doped β-SiAlON Phosphor
Authors: Li Li , Zhang Cheng , Jiang Dan Yu , Zhang Na , Li Cai Xia , Li Qiang
Published: September 2011

Eu2+ doped b-SiAlON (z = 1, 3, 4) phosphor were synthesized by carbothermal reduction- nitridation (CRN) using precursors powder as materials. The precursors powder prepared by sol-gel method using the SiO2, AlCl3×6H2O, Eu(NO3)3, ammonia water, carbon powders as starting materials. The CRN reaction proceeded at 1380°C for 6 h in an N2 atmosphere. Eu2+ doped b-SiAlON (z = 1, 3, 4) had high adsorption in the UV-visible spectral region. While z = 1, one bands were observed in the emission spectrum centered at about 425 nm monitored at 282 nm. The excitation bands centered at about 282 nm. While z = 3, one bands were observed in the emission spectrum centered at about 425 nm monitored at 282 nm. The excitation bands centered at about 282 nm. While z = 3, the emission spectra exhibit one bands with maxima at about 419 nm under 280 nm excitation. The excitation bands centered at about 280 nm. While z = 4, the emission spectrum centered at about 419 nm monitored at 280 nm. The excitation bands centered at about 280 nm. In this work, luminescence properties of Eu2+ doped b-SiAlON (z = 1, 3, 4) are independent of z value. It is possible related to the low synthesis temperature.
Thermal Decomposition of Dolomite Containing Phosphorus
Authors: Zhang Hong Wei , Fang Qin Fang , Guo Ying
Published: September 2011

In this paper,DTA-TG and TEM are used to investigate dolomite containing phosphorus. The investigations suggest that the thermal decomposition of dolomite containing a little bit of phosphorus powder has only one reaction while that of dolomite has two reactions, and the final temperature of the reaction reduces by about 18°C. The oxidation reaction of the phosphorus in dolomite begins at about 500°C, which is 140°C higher than that of the oxidation reaction of phosphorus in standard atmosphere condition. Round-bubble-shape structure gradually appears on the surface of the dolomite sample when observed using TEM. Furthermore, the number and size of this structure increased with the rising of the temperature. Finally, the round-bubble-shape structure breaks to small hollows, showing as teared-shape, and forms a series of protruding and intensive larger hollows and spherical shape. Therefore, the temperature of thermal decomposition of thermal decomposition of dolomite is decreased and the components of thermal decomposition products of dolomite containing phosphorus are almost the same as that of dolomite.
Study of Natural and Synthetic Quartz by Raman Spectra
Authors: Zu En Dong , Li Sheng Qing , Zou Yu , Zhao Xu Gang , Sun Yi Dan , Lin Yu Fei , Li He
Published: September 2011

The FWHM of Raman spectrum, which is the life-span of phonon, can provide valuable information of natural or synthetic gem. Through testing the natural and synthetic quartz by BTR111-785 mini-Raman spectroscopy, it is found that the FWHM of natural quartz is more than 30 cm-1, withal the FWHM of synthetic quartz is less than 30 cm-1.