bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibration Response Localization of Bladed Disk with Pre-Twist Mistuning
Authors: Wang Ai Lun , Cao Xu Hui
Published: February 2012

A new mistuning form, pre-twist mistuning was found in the bladed disk based on the engineering practice. Based on a continuous parameter model of bladed disk, the characteristics of bladed disk with pre-twist mistuning and natural parameters mistuning, including stiffness mistuning, mass mistuning and damping mistuning were compared and analyzed, and the effect of pre-twist mistuning on the vibration response localization of bladed disk was researched. The result shows that pre-twist mistuning can lead vibration response localization to bladed disk as well as natural parameters mistuning. The degree of vibration response localization caused by force mistuning is comparative with the natural parameters mistuning. Compared with natural parameters mistuning, the pre-twist mistuning could not change the natural characteristics of bladed disk. As a result, the pre-twist mistuning can not be detected by traditional method, such as the frequency test. The result not only completed the research content of bladed disk, but also conducted the design and manufacture of bladed disk.
Design and Simulation of Fully Integrated Micro Electromagnetic Vibration Energy Harvester
Authors: Tao Kai , Ding Gui Fu , Wang Pei Hong , Liu Qi Fa , Yang Zhuo Qing
Published: February 2012

A fully integrated micro electromagnetic vibration energy harvester based on MEMS technology is designed and its mechanical and electromagnetic characteristics are analyzed by using Finite Element method (FEM). Structure static, modal and harmonic analysis of spring-magnet system was carried out by ANSYS software. Ansoft Maxwell software was used to simulate the electromagnetic characteristics of the energy conversion system, especially the relationship between the output performances of the structure and parameters of the coil. The optimized model is designed and the optimization principles could provide a reference for the future electromagnetic vibration based harvester design.
Whisper Denoising in Joint Time-Frequency Domain Based on Real-Valued Discrete Gabor Transform
Authors: Zhou Jian , Huang Cheng , Zhang Man , Tao Liang , Zhao Li
Published: February 2012

Whispered speech can be effectively used for quiet and private communications over mobile phones and is also the communication means for ENT patients under a regime of voice rest. However, little progress has been made on the denoising of whispered speech in noisy environment because of its special acoustic characteristics.In this paper, we propose a whisper denoising algorithm in joint time-frequency domain based on real-valued discrete Gabor transform(RDGT). Noisy whisper is first transformed into the joint time-frequency domain by fast real-valued discrete Gabor transform. The MMSE based log-amplitude estimator is derived under speech presence uncertainty hypothesis. Clean whisper spectral is then estimated by inverse transform of RDGT. Experimental results show that the proposed algorithm is very effective in avoiding the musical residual noise and retaining weak speech components.
Design and Simulation of Fuzzy Self-Tuning PID Controller for Two-Link Robot
Authors: Jiang Jian Hu , Wu Chao , Zhang Gang
Published: February 2012

In this paper, fuzzy self-tuning controller is introduced first. The fuzzy model is built according to the experience of PID parameter tuning with fuzzy set theory. Parameter tuning is achieved by use of fuzzy ratiocination and decision according to actual response, which is applied for control towards robot. Mathematical model of two-link robot has been built as well as its geometric and dynamical equations through coordinate transformation and matrix operation. Finally, fuzzy PD controller with self-tuning method is applied to realize control towards robots. Simulation in Matlab has been carried out whose result shows that the control method proposed in this paper has better performance than the traditional ones.
An Investigation on Speedometer Pointer Residual-Value of Crashing Vehicle and its Application in Accident Reconstruction
Authors: Quan Yuan , Chen Xiao Qi , Li Yi Bing
Published: February 2012

According to the experience of traffic accident investigation over the years, the pointer of some crashed vehicles’ speedometer will stay in one place because of collision spread or heavily vibration, which may indicate the vehicle collision speed. However, the correlation between the residual speed value and actual vehicle collision speed still remains to be examined. For the practical needs of traffic accident reconstruction, this research work is carried out. Based on the principles of traditional speedometers, vehicle impact mechanics and failure mechanism, the damage and failure mode of speedometer in collision are studied. Through the statistics of 15 real traffic accident cases, the features and law about the pointer information of damaged speedometers are obtained initially. As an example, one of these cases is analyzed and calculated to verify the assumption. The availability of the mark information on the indicated place of speedometer after accidents (i.e. the correlation between the speed value of pointers and actual vehicle collision speed) is discussed, which can provide effective means and references for accident reconstruction and vehicle speed identification.
Hybrid RANS–LES Modeling for Unsteady Cavitating Flow Simulation
Authors: Gao Guo Hua , Zhao Jing , Ma Fei , Luo Wei Dong
Published: February 2012

A typical hybrid RANS-LES approach, DES (Detached Eddy Simulation), was introduced into cavitating flow simulation in this paper. The applicability of two DES models, including one equation DES model and SST k-ω DES model, and standard k-ε model was analyzed through experimental data of a water tunnel experiment. Validation results illustrate that the precision of DES method depends on the RANS model used and the length scale used to distinguish LES zone and RANS zone. The SST k-ω DES method can well predict cavitating flow. The averaged results gained through this model are better than those of standard k-ε or one equation DES model. By comparison, the one equation DES model shows little advantage than standard k-ε model to simulate cavitating flow.
Calculation for Circulating Velocity in Curved Channel
Authors: Tong Si Chen , Xu Guang Xiang , Zhong Liang
Published: February 2012

The hydraulic characteristics of curved channel flow are one of the most important subjects to hydraulic researchers and engineers. Among them the magnitude of circulation velocity and its calculation method is of great interests. Experimentation of generalized curved channel was carried out to explore the flow velocity parameters and circulation velocity characteristics by adopting the ADV to measure and analyze the 3D velocity datum. Theoretic formula was established for calculating the circulating velocity in the curved channel. Comparison with the results calculated from the formulas of other researchers the formula proposed in the paper is relatively quite good. The paper provides a basis to explore the hydraulic characteristics of the curved channel profoundly.
Wear Resistance Improvement of Titanium Bearings by Laser Gas Nitriding
Authors: Santos Edson Costa , Kida Katsuyuki , Rozwadowska Justyna , Honda Takashi , Koike H. , Kashima Y. , Kanemasu K. , Matsumoto Ryo
Published: February 2012

Superscript textThe influence of gas nitriding on commercial pure titanium and Ti-6Al-4V (Ti64) alloy bearings by using a Q-sw laser on the wear loss during rolling contact fatigue is investigated. By optimizing the laser processing parameters, such as laser scanning speed, power and beam diameter thin TiN coats of 0.5 to 3 µm were produced. Non-coated and coated bearings made of pure Titanium and Ti-6Al-4V alloy were tested in equal conditions and it was found that the titanium nitride layers significantly improve the rolling contact fatigue performance of titanium components. For tests up to 106 cycles the wear loss of the coated samples was at least ten fold lower than that of the uncoated ones and for 7.76 x 106 cycles, the wear resistance improved almost 100-fold.
Design of Large Branches Grinder Based on the Using of China's Biomass Power Generation
Authors: Yang Chun Mei , Yu Sheng Tong , Ren Chang Qing
Published: February 2012

The research of the large branches grinder is based on the requirements of China's biomass power generation to branches timber local processing. According to China's specific national conditions, the design of the existing branches grinder has been improved. By increasing the wooden grasping manipulator improves feeding efficiency and automation. The transmission mode of branches grinder has been changed. Switching to big diesel engine to drive it overcame the existing branches grinder’s dependence on electricity. Increasing the trailer chassis make it moved freely, which made the branches grinder crush the branches local.
Study on Adaptive Control of Restrained Cantilever Pipe Conveying Fluid
Authors: Bao Ri Dong
Published: February 2012

The cantilever fluid conveying pipe which restrained by linear spring and cubic nonlinear spring at its free end was studied. Firstly, the model reference adaptive control system with parallel structural style was designed for the restrained cantilever pipe based on Lyapunov theory of stability. Then the vibration of the pipe system was under positive controlled making use of this adaptive control scheme. Lastly, the numerical simulating method was used to verify the effectivity of this control method and the influence of system parameters on control performance and control input energy were also investigated. The simulation results showed that the control effect of the control system was extremely distinct. In addition, the larger the Lyapunov function state feedback declinational gains were, the better the control effect had, and the shorter the required time that the controlled system entirely settled down needed. With the position of piezoelectric actuator moved to the pipe free end the required time that the controller entirely settled down would become longer and longer. Moreover, the effect of the length of piezoelectric actuator on the controlled system was relatively complicated, the required time that fluid conveying pipe system settled down and the control energy took on complicated variation regularities.
Computer-Aided Design and Simulated-Mechanical Study of Individualized Femoral Prosthesis
Authors: Li Dong Song , Li Shu Qiang , Cai Bo , Feng Wei , Liu Jian Guo
Published: February 2012

Objective To construct three-dimensional models of individualized femoral prosthesis by using computer-aided design and to verify whether individualized femoral prosthesis is superior to popular femoral prosthesis via simulating and contrasting mechanical study. Methods Two-dimensional images of fresh femurs were obtained by using total-length CT scanning and processed with computer edge recognition and three-dimensional contour extraction software to identify outer and inner contour of pulp cavity, extract contour data of pulp cavity and prosthesis, and construct three-dimensional models of femur and individualized femoral prosthesis. SolidWorks software was used to establish three-dimensional prosthetic models in common biological and bone cement types; moreover, bone-cement, biological, and individualized femoral prosthesis were replaced via simulating clinical surgery. Results Edge extracting was replaced by Canny operator, characterizing by stable running, credible outcome, and consistent with the primary request. Stress, femoral stress, interface stress, and primary micro-motion of individualized femoral prosthesis were significantly lower than biological and bone-cement femoral prosthesis (P Conclusion The computer-aided design is reliable to perform the assistant design of prosthesis; furthermore, biomechanical properties of the individualized femoral prosthesis are superior to those of popular femoral prosthesis.
Experimental Modal Analysis and Modal Reproduce Experiment Research of a Chladini Plate
Authors: Ma Xun , Zhang Ji Wei , Yan Shi Ming
Published: February 2012

By means of ANSYS Workbench, different materials, dimensions and shapes of the Chladni plates are simulated. The natural frequency and Modal are obtained so that the chladni plate is determined and manufactured, that is used in the experimental research. Then, modal analysis test is conducted by Experimental modal analysis, the resonance and modal characteristics of the plate between 1Hz to 1000Hz are identified. Finally, Modal reproduce experiment is conducted under the acoustic excitation. Experimental and analytical results show that the finite element analysis, experimental modal analysis and Modal reproduce experiment basically have the same results.
Formability of Tailor Welded Blanks Based on the Improved Rule of Mixture Considering the Welding Residual Strain and Stress
Authors: Song Yan Li , Hua Lin
Published: February 2012

In this paper, the rule of mixture, which is often used to derive the weld properties from the uniaxial tension test of a subsize welded specimen, was improved by taking the residual welding strain/stress into account and assuming iso-strain increment across the welded specimen. Based on this improved method, hardening data of two different tailor welded blanks were determined. Erichsen cupping tests were performed experimentally and numerically to evaluate the effects of welding residual strain and stress on TWB formability. The results indicate that: (1) the residual strain and stress affect the formality of TWBs to some extent and (2) neglecting the welding residual strain and stress may predict a delayed crack onset and relatively large values in the maximum punch load and Erichsen index.
The Deformation Character of Retaining Wall under Horizontal Earthquake
Authors: Jiang Kai Yu , Cao Jing , Peng Lei , Chen Ming Ming
Published: February 2012

The soil pressure can be influenced by the deformation of retaining wall because of the interaction of wall and soil. The dynamic soil pressure and plastic bottom displacement induced by earthquake action will subsequently result the deformation of the wall. The dynamic soil pressure will vary with the wall deformation and, on the other hand, change the deformation of the wall. The wall under lateral earthquake is assumed to be a single freedom system, thus only one deformation mode is considered in this paper. Based on this assumption, the differential equation of wall-soil dynamic interaction system is proposed.
Evaluation Dispatching Rules for Two-Stage Hybrid Flow Shop Scheduling with Parallel Machines
Authors: Kaweegitbundit Parinya
Published: February 2012

This paper considers two stage hybrid flow shop with identical parallel machine and evaluate performance of common dispatching rules; shortage processing time (SPT) longest processing time (LPT) earliness due date (EDD) and first in first out (FIFO). The objectives are to determine makespan and total tardiness have been minimized. To evaluated performance of dispatching rules, the results have been compared on each criterion. The experimental results show that SPT outperform than other rules with minimizes makespan as an objective function for all problems. On the other hand, for minimize total tardiness as an objective. The EDD rule outperform than other rules.
Tensile Behavior of Rolled and Annealed Copper Thin Foils
Authors: Jung Taek Kyun , Lee So Young , Kim Tae Bum , Kim Kyung Hoon , Lee Hyo Soo , Kwon Hyouk Chon
Published: February 2012

Tensile properties of rolled and annealed copper thin foils were investigated based on the grain size and thickness. Yield strength was higher in the thinner foil than in the thicker foil at as-rolled state. Difference of yield strength between the thinner foil and the thicker foil becomes small at annealed state. Tensile strength was higher in the thinner foil than in the thicker foil at as-rolled state, but it was reversed at annealed state. Strain to fracture or elongation increased with increasing thickness in the annealed state. A knife edge type of fracture was characterized in both the as-rolled state and the annealed state. A higher tensile strength and strain to fracture of the annealed thicker foil was attributed to the higher number of grains per thickness. From this work, it was concluded that mechanical properties of thin foils were dependent upon the number of grains per thickness.
Marine Diesel Engine Speed Control System Based on Fuzzy-PID
Authors: Shen Xiao Qun , Su Yu Xiang
Published: February 2012

The traditional PID control effect is not ideal when the controlled object is nonlinear and contains variable parameters. In order to adapt marine diesel engines to variable working conditions, the fuzzy-PID control method was proposed to be used in the speed control system of marine diesel engine to realize online adjustment of PID parameters. The composition of marine diesel engine speed control system was introduced, and the design of fuzzy–PID controller was analyzed in detail. The fuzzy-PID diesel engine speed governor was simulated through MATLAB. The simulation results show that fuzzy-PID can improve the system dynamic performance, reduce system oscillation and improve the response speed. The results also show that the fuzzy-PID marine diesel engine speed governor has high anti-interference ability and strong robustness.
Theoretical Research on Microwave Assisted Magnetic Moment Reversal in Magnetic Recording Media
Authors: Li Shuang Mei
Published: February 2012

The minimum switching field threshold and switching speed are key parameters for the magnetic recording in writing. This paper presents the dynamic precession of the moments of the grains based on LL equation.Under microwave-assisted reversal conditions, the influence of the differences between the angle of Anisotropy field on the magnetic moment reversal and loading speed of reversal magnetic field in two interacting particles is investigated.
Signal Processing System for Wheel Speed Measurement Based on FPGA
Authors: Zhang Chun Fu , Yan Qi Jin
Published: February 2012

In this paper, a new Hall sensor’s layout for wheel speed measurement is introduced and the corresponding signal processing system is designed, based on the principle of orthogonal signal subdivision. The system implements the function module of filter, subdivision, gated counter and output interface with FPGA and the simulation results prove its wide measurement range, high measurement precision and stabilization. Compare to the traditional wheel speed measurement, this system has prominent measuring speed under a low speed condition.
Research and Design of the New Investment Casting Production Line
Authors: Chou Xing Rong , Kang Yong Xing
Published: February 2012

To reduce the energy consumption of investment casting production, reduce labor intensity and improve product quality and production efficiency,a investment casting production line of automation and low energy consumption has been researched and designed. The major equipments of the new production line were designed, such as energy-saving roaster, casting conveyor, roasting car,stop-mechanism,off pieces-machine, etc.The annual production capacity of the production line builted is increased by 23%, the rejection rate is reduced by 30%, the average rate of liquid steel products is increased by 5%, the annual supplies and energy saving is 3 times the investment.
The Design for Computer Monitoring System Based on Ethernet
Authors: Xie Chuan , Wang Hong
Published: February 2012

Ethernet computer monitor and control system is a new strategy subjecting to the problems existing in the Ethernet. The computer monitor and control system designed in this paper adopts C/S mode. It’s composed of client monitor software and server software. The five modules of the client monitor software are used to record the statistic analysis of the network usage state, the modification of the file information, the information of the running process, the information of the E-mail, and the use efficiency of CPU. The server software is in charge of collecting all kinds of information of client so that it is easy for the user to monitor and manage the host.
Turbocharged Solid Propellant Ramjet for Tactical Missile
Authors: Yang Sa , He Guo Qiang , Liu Yang , Li Jiang
Published: February 2012

Turbocharged solid propellant ramjet (TSPR) is the combination of solid propellant gas generator air turbo ramjet (ATR)with solid ramjet, is cycle of augmented ATR, the parametric performance calculation were carried out for TSPR, The effects of independent design parameters including parameters of compressor and turbine and propellants were studied and the preferred compressor, turbine and propellants were obtained for TSPR; The operation envelop of TSPR and ATR were obtain under the preferred component limitation, the results shows that TSPR offers wide speed-altitude operation envelope, high specific thrust, high specific impulse, it is combining the advantages of the ATR and solid ramjet, and suitable for tactical missiles application meets potential requirements for boosting and cruising.
On XFEM Applications to Crack Surface under External Force
Authors: Yu Tian Tang , Shi Lu Yang
Published: February 2012

The extended finite element method is applied to modeling growth of arbitrary crack with crack surface tractions. Firstly, the extended finite element method is investigated for the stress intensity factor solution of surface traction problems. Secondly, for different water pressure acting on the crack surfaces and different crack length, the variation of the stress intensity factors is investigated. Finally, the process of hydraulic fracturing is simulated with the method. Numerical simulations illustrate that the method can effectively model the fracture problems with surface tractions.
The Development and Application of Super-Lightweight Aggregate Pumping Concrete
Authors: Gao Chun
Published: February 2012

Applied in the construction of Wuhan railway station of the Wuhan-Guangzhou high-speed railway, the super-lightweight aggregate pumping concrete has been developed by the independent study on the tackifier, the substitute of lightweight aggregate for sand and tackifier for sand. The concrete has been used for 58000m3. The dry bulk density of the lightweight aggregate concrete is controlled at 1160kg/m³. And the concrete has a good performance in the homogeneity and working condition, and is easy for pumping.
3D Numerical Simulation of Compressible Gas Synthetic Jet
Authors: Ding Ying Tao , Liu Ru Qing , Su Ri Na
Published: February 2012

Based on standard k-ε turbulent, PISO algorithm and the dynamic mesh model, numerical simulation of the 3D, viscous, unsteady compressible gas synthetic jet model was proposed. Two kinds of diaphragm boundary conditions， Helmholtz frequency characteristics and other factors affecting the performance of the 3D synthetic jet were discussed. Simulation results show that the dynamic mesh diaphragm boundary condition is more consistent with the experimental results and the theoretical results, which demonstrates the rationality of the dynamic mesh 3D compressible gas model.
Metallographical Image Segmentation and Compression
Authors: Sun Qiu Dong , Gao Shun Fu , Huang Jiang Wei , Chen Wei
Published: February 2012

The double-threshold binarization and morphological transform were applied to process the metallographical image. They could classify the grain and the grain boundary from gray metallographical image. Also, the eight-direction tracking techniques about Freeman chain encoding for metal metallographical compression had been discussed, and a grain boundary tracking algorithm was given. The experimental result shows that the proposed image processing method can segment grains and their boundaries efficiently. Freeman chain encoding can compress the stored data of metallographical image greatly. Compared with another compression method RLE, it has much higher compression effect.
Pressure Behavior of a Coupling Model with Variable Permeability Effect
Authors: Fu Xiang , Li Xiang Fang , Cheng Shi Qing , Huang Liang , Nie Xiang Rong
Published: February 2012

It is indicated that the fluid flow does not abide by the Darcy law in certain low permeability reservoirs. The results of pressure date analysis in these low permeability reservoirs would be inaccurate when generalized using Darcy flow models. To improve analysis results, based on the concept of variable permeability effect, the dual non-Darcy coupling flow model is established in this paper. The iterative algorithm is adopted to solve the differential set of equations. This work also describes the pressure behaviors by pressure response curves.
Effect of Aging Temperature on the Microstructure and Mechanical Properties of 1000MPa Grade Low Carbon Bainitic Steel
Authors: Zuo Long Fei , Wei Zhan Lei , Ni Ri , Ma Ben , Wang Zi Dong
Published: February 2012

A kind of 1000MPa low carbon bainitic steel belonged to the Fe-Cu-Nb series was hot rolled and aged, the influence of aging temperatures on the microstructure and mechanical properties of the steel were investigated by using Scanning electron microscopy (SEM) and transmission electron microscopy(TEM). The results show that the microstructure of the low carbon bainitic steel consisted of lath-shaped bainite(LB), granular bainite(GB) and quasi-polygonal ferrite(QF), and the proportion of each kind of microstructure changed with the aging temperatures. The strength of steel with the increase of aging temperature first increased, then decreased, Aging temperatures had distinct effect on yield strength of the tested steel, and less effect on the ultimate tensile strength, we can get the best comprehensive properties yield strength 1011.87 MPa and elongation rate 16.38% of good tough match aged at 450°C. Through analysis it is concluded that the strength of the tested steels aged at 450°C reaches the maximum value, which is attributed to the precipitation of a large amount of fine ε-Cu particles(5~10nm) and a small number of(Nb,Ti)(C,N) precipitates.
Effect of Temperature and Moisture Content on Thermal Conductivity of Green Teas
Authors: Yan Jian Wei , He Lin , Yang Liu Yong
Published: February 2012

The thermal conductivity of green teas has been used as engineering parameter in the design of processes and machines for drying, storing and aeration. The thermal conductivity of green teas was determined and its changes with moisture content, bulk density investigated. The thermal conductivity values of green teas increased from 0.036 to 0.438 W m–1 K–1 and from 0.041 to 0.568 W m–1 K–1 for low and high (loose and dense) bulk densities, respectively, as the moistSuperscript texture content increased from 5.3 to 78.7% dry basis. The change of the thermal conductivity of green teas with temperatures at different bulk densities shows that it increased from 0.035 to 0.045 and 0.042 to 0.053 W m–1 K–1, respectively, as the temperatures and bulk density increased. The thermal conductivity values obtained with the high bulk density was higher than those obtained with the low bulk density for green teas.
Impact Response and Energy Absorption of Aluminium Foam-Filled Tubes
Authors: An Yang , Wen Cui E , Hodgson Peter D. , Yang Chun Hui
Published: February 2012

The effect of foam fillers on the impact behaviour and energy absorption of an aluminium tube is investigated. Both experimental test and computational simulation are employed in current study. For comparison, hollow tubes and foams are also tested, respectively. Foam filler is found to be ineffective in increasing the crushing loads of the composite tubes over the simple superposition of the crushing loads of hollow tube and foam. Also, foam filler increases the tendency for the concertina mode of folding. The foam fillers of tubes additionally result in increasing the SAE values over those of hollow tubes.
Springback Angle and Plastic Elongation Prediction of Thin-Walled Tube Bending by FEM
Authors: Dan W.J. , Zhang W.G.
Published: February 2012

Springback is an inevitable phenomenon while the load is released due to the elastic property after tube bending. This leads to an increase in the radius of curvature and elongation by plastic deformation, a reduction in the bending angle of the bent tube, a decrease in dimensional accuracy and fits with others difficulty. By elastic–plastic finite element methods (FEM), a reasonable simulation model for thin-walled tube bending is established to define the relationships between process parameters and springback angle, plastic deformation. With 210 kinds of models, the results show that: 1) Springback angle and plastic elongation of bending tube are related to bending angle, bending die diameter and tube thickness. 2) Controlling functions for plastic elongation and springback angle in bending tube process are given, which is verified by tube bending experiments.
Preparation of Polyurethane Immobilized Nitrifying Bacteria Pellets and Application to Treatment of Micro-Polluted Source Water
Authors: Jin Yong Wei , Dong Ya Mei , Zhang Zhen Jia
Published: February 2012

The preparation and application of polyurethane immobilized nitrifying bacteria pellets for surface water treatment was studied. The removal of ammonia nitrogen from micro-polluted source water by polyurethane immobilized nitrobacteria pellets with a stuffing ratio of 10% in volume in an up-flow inner circulation reactor was investigated with the system operated continuously under the following conditions: temperature 20°C--30°C, DO 3--5 mg/L, and pH 7.1--7.3. The continuous removal rates of NH4+-N remain above 90% and 4+-N concentration in the produced water was less than 0.5 mg/L with the hydraulic reaction time (HRT) controlled at 0.5 h. The results verified that polyurethane immobilized nitrobacteria pellets have a great potential for micro-polluted source water treatment applications.
Rapid Growth and Magnetic Properties of Fe7CO3 Intermetallic Compound
Authors: Zhang Yuan Yuan , Yao Wen Jing , Sun Wen , Wang Jian Yuan , Han Xiu Jun , Wang Nan
Published: February 2012

By drop tube and melt spinning techniques, rapid growth of Fe7Co3 intermetallic compound has been realized. The microstructures and nucleation characteristics under different cooling rates are investigated. With the increase of cooling rate, Fe7Co3 intermetallic compound grains are refined in both rapid growth manners. Experimental observation and theoretical analysis indicate that the nucleation rate in single-roller quenching is much greater than that in free-fall method when the cooling rate is under a same level. The comparison of magnetic property between the alloy ribbons and other dimensional magnetic material were made. The superior soft magnetic properties of Fe-Co alloy ribbons changes sensitively with the cooling rate, which is mainly decided by the wheel velocity.
Stabilization of Variable Rope Length Pendulum Using Lyapunov's Theory and Differential Geometry
Authors: Bláha Lukáš
Published: February 2012

In this paper, we investigate the motion of variable rope length pendulum as basic part of a portal crane. Our starting point is a discussing the behavior of that system for variable range of condition. We show the basic control strategy that damps the oscillation of hanging pendulum. This control law is developed using Lyapunov's method and recently analyzed by [2]. Further, the control strategy is improved in the sense of faster damping resulted from differential geometry.
Research on Lattice Distortion Modification Processing Technology of Cotton/Linen Fiber and Yarn
Authors: Zhu Zi Na , Meng Zhuo , Zhu He Lei , Sun Yi Ze
Published: February 2012

For cotton/linen fibers, yarns and other textile raw materials have natural weak points such as rough, easy to wrinkle and shrink, poor dyeability and so on, which are bad for clothing, this paper develops a lattice distortion modification processing technology of cotton/linen fibers and yarns, including the modification equipment and the process flow. After processed by this new modification technology, the performances of cotton/linen fibers and yarns, like softness, smoothness, fluffiness and dyeing properties improved significantly, which meet the product's quality requirements. Therefore, this lattice distortion processing technology can be popularized as a basic technology in the textile field.
Research on Protective Method of Amino in Chitosan
Authors: Shang Xiao Xian , Zhao Bo , Zhang Xiao Meng
Published: February 2012

Two kinds of chitosan derivatives are made by adopting Schiff alkaline method and amino protonation method to modify the amino in chitosan. Deprotection to amino is conducted under the condition of both acidity and alkalinity. It turns out that these two kinds of methods can both be protective to amino in chitosan. And deprotection contributes to more convenience. Impurities brought by chitosan modified products made out of Schiff alkalinity method are lot. By means of deprotection, output of products is higher. Compared with Schiff Alkalinity method, the impurities brought by modified products made out of amino protonation method are lesser with a comparatively low productivity.
Research on Lubricating Capability of Gear Oil Pump with the Arc-Cycloid Tooth Profiles at Meshing Zone
Authors: Zhang You Chen
Published: February 2012

Gear oil pump with the circle-arc and cycloid tooth profiles is a kind of inner meshed gear pump. The research on lubricating capability of the kind of pump is very lacking, though they are widely applied for many fields. The lubricant medium film thickness was calculated and the change trends of film thickness were found, combining characteristic of pump with the arc-cycloid tooth profiles. Calculating results indicate that full film lubrication can be easily formed at meshing zone when the pump was running. This shows that meshing efficiency of this kind of gear pump was good and wear quantity was small.
Numerical Analysis Technique to Estimate the Reliability of a Disc Brake System – Hot Judder Simulation
Authors: Do Hyun Jung , Sung Pil Jung , Won Sun Chung
Published: February 2012

Hot judder characteristics of a ventilated disc brake system are discussed. Three dimensional finite element models of the ventilated disc, pads and pistons are created, and a fully coupled thermo-mechanical analysis of the hot judder phenomenon of the disc brake system is performed using SAMCEF. The brake dynamo test is carried out according to the high speed judder test mode. The evolution of the temperature distribution on the disc surface is described, and the hot spot generation process is investigated. The simulation results such as the maximum disc temperature, BTV are compared to the data from the dynamo test, and the reliabilities of the analysis technique and simulation model presented in this paper are verified.
Computation of Theoretical Stress Concentration Factor of V Shaped Notch Tip
Authors: Zhang Li Jun , Xue Jie Qiong , Zhao Yong Rui , Xiang Heng Fu
Published: February 2012

To obtain the crack life and value of the external load applied on the bar in the course of the bar precision cropping, the mathematic expression of the theoretical stress concentration factor in the tip of the V shaped notch containing its geometric parameters is built theoretically by analyzing the stress field distribution of V shaped notch tip and the stress intensity factor. The influences of the flare angle Φ, the radius at the groove bottom, and the groove depth d on the theoretical stress concentration factor are analyzed in detail and the obtained rational value is d/D=0.1 , s/D=0.015, Φ=90 in engineering practice. The analytical results show that the data obtained by the mathematic expression of theoretical stress concentration factor in the tip of the V shaped notch presented in the paper are coincident with the results of the corresponding parameters obtained by stress concentration manual in some extension.
Microstructures and Thermophysical Properties of Polymer Derived SiC/C Composites
Authors: Han Xiao Yi , Cheng Hai Feng , Xing Xin , Wang Jun
Published: February 2012

Polymer derived SiC ceramics usually present a relatively low thermal conductivity for the large porosity and complex phases. In order to obtain condensed SiC ceramic with low thermal conductivity, a preceramic precursor polycarbosilane (PCS) was selected as the raw materials. And hot press sintering processes were performed at 1600 °C under Ar atmosphere with the holding time in the range of 20 to 40 min for consolidation. The microstructures and phases were analyzed by scanning electron microscopy (SEM) with energy disperse X-ray spectroscopy (EDS), X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The specific heat, thermal diffusivities and thermal conductivities were measured and investigated from room temperature to 650 °C. A minimum thermal conductivity of 4.13 W•m-1•K-1 was obtained at 650 °C with a holding time of 30 min.
Influence of Position Initiation Error on Formation of New EFP
Authors: Wang Feng , Du Zhong Hua , Gao Jie Dong , Dong Yu Cai
Published: February 2012

Position initiation error shows great influence on new EFP. It not only causes the way of crushed liner by detonation wave at initial phase, but also influences wave front to show asymmetric. Finally it influences detonation wave collision effect to make penetrator slope. The influence of position initiation error on new EFP was studied in numerical simulation. As increase of position initiation error, tilt trend shows faster. For different length of charge, position initiation error shows different collision effect. Position initiation error shows greater influence with smaller length charge than larger.
A Gyro-Based Inclinometer for Oil and Gas Well Logging
Authors: Wei Biao , Feng Peng , Mi De Ling , Ren Yong , Yang Fan , Zhao Qiao Hong
Published: February 2012

To satisfy the requirements of the oil and gas explorations in harsh conditions, an inclinometer based on dynamic tuning gyroscopes was developed. This inclinometer has remarkable temperature and pressure resistance which can be operated under with temperature higher than and pressure greater than . The azimuth angle error is less than and the error of elevation angle is less than . The results of in situ test indicated that this system is can meet the requirements of the oil and gas explorations which needs the azimuth error and slope angle error and is feasible for practical use.
Improved Hilbert-Huang Transform and its Application in Seismic Data Spectrum Decomposition
Authors: Bing Ping Ping , Cao Si Yuan , Lu Jiao Tong
Published: February 2012

In the conventional seismic data time-frequency analysis, the wavelet transform, wigner ville distribution and so on, cannot meet the high precision time-frequency analysis requirements because of uncertainty principle and cross-term interference. The recently popular Hilbert-Huang transform (HHT) although overcomes these conventional methods’ deficiencies; it still has some unsolved deficiencies due to the theory imperfect. This paper focuses on an improved HHT so as to ameliorate the defect of original HHT. First of all, the wavelet packet transform (WPT) as the preprocessing will be used to the inspected signal, to get some narrow band signals. Then use the empirical mode decomposition (EMD) on the narrow band signals and get the real intrinsic mode function (IMF) by the method of correlation coefficient. From the numerical study and comparison of improved HHT, wavelet transform and HHT, it proves the validity and advantages of this improved method. At last, the improved HHT is applied to marine seismic data by the spectrum decomposition technology, and it well reveals the low frequency shadow phenomenon of the reservoir. The results show that this new method has effectiveness and feasibility in seismic data spectrum decomposition.
A Prediction of the Optimal Blank Contour of an Inner Elliptic Flange from Flanging
Authors: Kwan Chin Tarn , Chang Jui Tsai
Published: February 2012

In this paper, the finite element method is employed in conjunction with the abductive network to predict the optimum blank contour of an inner elliptic flange with unevenness in the flanging process. Different flange heights combined with various aspect ratios of the inner elliptic flange are taken into account as the process parameters in this study. A finite element-based code is utilized to investigate the material flow characteristics under different process parameters, and the abductive network is then employed to synthesize the data sets obtained from numerical simulations, thus establishing a predictive model. From this model, an optimal blank contour for producing an elliptic inner flange with unevenness can be found.
To Analyze the Effects of Geometric Misalignment in a Cylindrical Pressure Vessel
Authors: Abbas Musharaf , Israr Asif , Rehman Atiq Ur
Published: February 2012

This particular work consider a pressurized vessel typically made of high strength low alloy steel and containing the geometric misalignment at the cylinder-to-cylinder junction. This misalignment produce in the vessel’s structure is because of girth weld that is evident in most of the fabrication of such type of structures apart from other factors which is beyond the scope of this study. This study evaluates the geometrical effects of mismatch on the structural integrity of the pressure vessel and prediction of stresses at the affected area of the cylinder. Analytical and Finite Element (FE) approaches are employed to analyze the configuration. FE analysis is performed by the use of ANSYS on one quarter of the structure due to symmetry. FE results are also compared with the analytical results of different authors. In addition, maximum allowable mismatch is also determined and is a part of this study.
Evolutive Laws and Constitutive Relations in Nonlocal Viscoplasticity
Authors: de Angelis Fabio
Published: February 2012

In the present work the evolutive laws and the constitutive relations for a model of nonlocal viscoplasticity are analyzed. Nonlocal dissipative variables and suitable regularization operators are adopted. The proposed model is developed within the framework of the generalized standard material model. Suitable forms of the elastic and dissipative viscoplastic potentials are defined and the associated constitutive relations are specialized. The evolutive laws for the proposed nonlocal viscoplastic model are presented in a general form which can be suitably specialized in order to include different models of nonlocal viscoplasticity.
Correlating Strain and Acoustic Emission Signals of Metallic Component Using Global Signal Statistical Approach
Authors: Mohammad Mazian , Abdullah Shahrum , Jamaludin Nordin , Nuawi Mohd Zaki
Published: February 2012

This study clarifies the fatigue properties using global signal statistical approach during the crack initiation stage for metallic component. Strain loading and acoustic emission (AE) signatures are captured simultaneously in the form of signal waves recorded by strain gauge and AE transducer. An initial study was carried out in the laboratory on medium carbon AISI 1045 steel specimens at constant amplitude cyclic loading condition, which lead to the fatigue failure characteristics. This study was carried out to investigate the relationship between strain and AE signals in order to make sure that AE technique also can be used as a detecting and monitoring crack initiation in metallic specimens. To achieve the goal, three different loads were applied on three specimens to capture the differences of the signals. The specific data acquisition systems were used to collect strain and AE signatures. For the purpose of analysis, the method of root mean square (r.m.s) and the kurtosis were used. The r.m.s value was used to quantify the overall vibrational energy content whereas the kurtosis was then used because of its sensitivity to high amplitude events. Based on these statistical approaches, the correlation patterns between both signals are expected to give a meaningful baseline to predict and monitor crack initiation of a metallic specimen.
Die Design of Aluminum Bipolar Plate Fabrication by Stamping Process and its Investigation
Authors: Kwon H.J. , Jeon Y.P. , Kang Chung Gil
Published: February 2012

A Proton Exchange Membrane Fuel Cell (PEMFC) is a type of fuel cell being developed for automotive applications as well as for stationary fuel cell applications and portable fuel cell applications. Its performance such as power density can be improved by the use of the bipolar plate with a new lightweight material which is one of core components making up PEMFC stack. Aluminum alloy has good mechanical properties not only in terms of density, electrical resistivity and thermal conductivity, but also in terms of corrosion resistant compared with stainless steel and graphite composites bipolar plate. Furthermore, the use of aluminum for a bipolar plate reduces simultaneously the cost and weight of it, and it contributes to the ease of machining. For these reason, an aluminum alloy is selected in this study. This study presents the feasibility of the simulation for the development of aluminum bipolar plates that consists of multi array micro channels. The analytical solutions obtained by the simulation are validated by the comparison with the experimental results. From the results, it is ensured that the stamping processes for the bipolar plate could be predicted and designed by the results of the by FE-Simulation.
Effect of Punch Profile on Thickness Distribution in Hydromechanical Deep Drawing of Conical-Cylindrical Parts
Authors: Mashhadi M. , Hashemi A. , Bakhshi-Jooybari Mohammad , Gorji A.
Published: February 2012

Hydro-mechanical deep drawing assisted with radial pressure (HDDRP) is used in industry to produce complex parts from sheet metals. This process is affected by parameters such as : pressure path, geometrical parameters of punch and die, friction between punch and sheet, etc. Investigating these parameters to acquire optimal parameters to produce the desired part is essential. In this study, the effects of the radius of punch tip and the radius of the transition zone from conical to cylindrical geometry, on forming and thickness distribution of parts have been studied. In performing the investigation, a specific geometry was considered for punch and different radiuses for punch tip and the transition zone were selected. The type of the sheet material examined is St14 steel. First, the process was simulated by the finite element simulation software, ABAQUS 6.9, and then some experiments were done to check the accuracy of the simulations. There is an acceptable conformity between the results. The results showed that the radius of punch tip is more effective than that of the transition zone, so with increasing the radius of punch tip, the minimum thickness increases and thickness distribution becomes more uniform.
Study of the Effect of Material Properties and Sheet Thickness on Formability of Conical Parts in Hydro-Mechanical Deep Drawing Assisted by Radial Pressure
Authors: Hashemi A. , Mashhadi M. , Bakhshi-Jooybari Mohammad , Gorji A.
Published: February 2012

Conical parts have a lot of usage in industries. Therefore, it is important to form these parts with high accuracy. In sheet forming processes, producing conical parts is one of the most difficult aspects. The two major problems that occur in the production of conical parts are rupturing and wrinkling. Among the forming processes for producing conical parts, the most capable one is hydroforming deep drawing. In this study, the effects of material properties and initial sheet thickness on forming and thickness reduction of the part were examined by using hydro-mechanical deep drawing assisted by radial pressure. For investigating these two parameters, pure copper and st14 steel are used. In experimental evaluation, sheets with thicknesses of 2.5 mm were used. In the simulation study, the thicknesses of 0.5, 1, and 2 mm were also examined. There is a good agreement between experimental and simulation findings. The results showed that for thinner sheets, the thickness reduction is less, and thus, a more uniform thickness distribution curve was obtained. Also, it was illustrated that for St14 steel sheet the thickness distribution curve will be more uniform compared with that of pure copper sheet.