bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study on Optimal Matching of Power System of Hybrid Hydraulic TLT
Authors: Zhao Li Jun , Li Guo Jun , Jiang Ji Hai
Published: March 2010

According to the running characteristic of an aircraft tractor and the specificity of serve target, the hybrid hydraulic system program is proposed. In the use of Adopting Simulated Annealing Genetic Algorithm, for the demand of aircraft tractor’s system, the multi-objective is transformed to a single objective function of the automobile’s dynamic performance and fuel economy performance by using the linear weighted method. Then the mathematical optimizing model of the powertrain is established, through calculating, reasonable parameters are gotten. The analysis of the simulation results shows that the comprehensive performance of the automobile has been remarkably promoted. On the basis of previous work, the system pressure of different weight aircraft models of traction has been optimized in order to give full play to the vehicle's performance. The research has important reference value for the theory analysis of hybrid systems and engineering applications.
Study on Edge Detection Technique in Material Bag Image
Authors: Zhang Tian Hou , Li Chang Chun , Wang Shi Feng
Published: March 2010

According to the features of material bag image, the paper compares an analyzes the detection effects of different edge detection operators detecting material bag image. A new image segmentation method is proposed to combine Sobel edge detection operator and iterative threshold. The method can extract edge information of material bag image efficiently and provide a theoretical basis for the robot automatic recognition of material bags technique.
The Design of New Type Muffler Used For Steam Turbine’s Exhaust Device
Authors: Yao Jing Hong
Published: March 2010

The exhaust device of steam turbine usually establishes vacuum rapidly using steam injection. The gas of the nozzle of the exhaust mixing device emits at high speed. The noise is very large. The muffler is designed to reduce the noise of the steam turbine’s exhaust devices. Referring to the principle of the separated expansion chamber muffler and connecting with practical production, we present a new type muffler. The design considers fully the peak frequency of the jetting noise of the nozzle and the noise attenuation of sound waves in the pipeline transmission etc. The muffler is small, light, anti- high- temperature and high-speed gases, and easy to be installed. The effect of noise reduction is obvious.
Bifurcation and Chaos of a 4-Side Simply Supported Rectangular Thin Electro-Magneto-Elastic Plate in Many Fields
Authors: Zhu Wei Guo , Bai Xiang Zhong
Published: March 2010

The problem of bifurcation and chaos in a 4-side simply supported rectangular thin electro-magneto-elastic plate in electro-magnetic, mechanical and temperature fields is studied. Based on the basic nonlinear electro-magneto-elastic motion equations for a rectangular thin plate and expressions of electromagnetic forces, vibration equations are derived for the mechanical loading in a nonlinear temperature field and a steady transverse magnetic field. By using Melnikov function method, the criteria are obtained for chaos motion to exist as demonstrated by the Smale horseshoe mapping. The vibration equations are solved numerically by using a fourth-order Runge-Kutta method. Its bifurcation diagram, Lyapunov exponents diagram, displacement wave diagram, phase diagram and Poincare section diagram are obtained for some examples. The characteristics of the vibration system are analyzed, and the roles of parameters on the systems are discussed separately as well, such as electromagnetic field intensity, temperature and mechanical force.
Efficiency- Reinforcement Technology Study for Hydraulic Reciprocating Sealing Based on TRIZ S-Field Analysis
Authors: Zhang Fu Ying , Zhang Qing Qing , Wang Ping
Published: March 2010

The dynamic seal mechanism of hydrodynamic reciprocating sealing is discussed. TRIZ S-Field model and standard solutions is proposed. The reliability and effectivity S-Field models of hydrodynamic reciprocating sealing are constructed according to typical hydrodynamic reciprocating sealing configuration shapes, such as O-ring sealing, Y-ring sealing and polymer sealing. The leakage and failure problems solutions of hydrodynamic reciprocating sealing as well as their configuration realization are studied based on TRIZ S-Field analysis and standard solutions, which offer powerful theoretic guides for efficiency-reinforcement technology of hydrodynamic reciprocating sealing.
The Principle Studies of Series Multistage Axial Ram Pumps and the Fluctuation Analyses
Authors: Wen De Sheng , Zhang Yue Zhong , Sun Jiang Bo , Du Li Bin , Li Yong An , Lv Shi Jun , Yang Peng , Liu Yi Shan
Published: March 2010

Through the research of closed-circuit type, semi-open type, all open-circuit type multistage series axial ram pump , we analysis flow volatility of series pump, and have carried out the two-stage all open-circuit type series axial ram pump experiment. Through the experiment, we have proven the open-circuit type series multistage pump is feasible. We have find a new way to realize the ultra-high pressure,high flow axial ram pump.
Detection of Small Damage of Beam Structures Based on the Slope of Proper Orthogonal Mode
Authors: Wang Dan Sheng , Zhang Ying Bo , Yang Hai Ping , Zhu Hong Ping
Published: March 2010

In recent two decades, the issues on structural damage detection and health monitoring have been paid considerable attention in mechanical and civil engineering communities. A lot of researchers have developed many methods to try to resolve the problems. To this day, detection of the small damage of structures, however, has still been a difficulty. The correlation theories of proper orthogonal decomposition (POD) and the basic principle of a new structural damage detection method based on the slope of POD are introduced in this paper. Numerical study on beam structures for small damage detection based on the proposed method is implemented. From the study results one can find that the method based on the slope of the difference of proper orthogonal modes (POMs) has the abilities to localize the small damage of beam structures.
New Type of Cantilever Crane for High-Speed Railway Track Plate Constructions
Authors: Zhang Yao Hui , Zhao Cun Bao , Chen Shi Tong
Published: March 2010

In China, the high-speed railway construction is growing rapidly currently. As laying the high-speed railways’ track plates accurately is an important part of construction, a large number of multifunctional advanced special cranes are required in order to complete the construction task on time. In the paper, the advanced design and application of the new type large cantilever special crane, which being used in the high-speed railway track plate constructions of Jinghu railway, Huning railway and Guangshengang railway, is introduced. The special main characteristics of the new type multifunctional large cantilever are described, such as easy to be assembled, easy to change the span, the cantilever beams can being folded, can being used in the tunnel, and so on. The successful applications of the new type crane have solved a number of difficulties in the track plate constructions, and have obtained obvious economic returns and social returns.
Study on a Capacitive Micro-Mechanic Gyroscope
Authors: Shi Yun Bo , Tan Qiu Lin , Zhang Qiong , Liu Jun
Published: March 2010

A micro-mechanic gyroscope design, which is used electrostatic comb driven, grid structure and capacitive detection, as well as its working principle, was proposed. Simulation and mode analysis using ANSYS were done while the simulation was consistent with theory. This gyroscope was designed and manufactured by body silicon technique, and after packaged, we got this gyroscope finally. The preliminary experiment test result showed that the first natural frequency is 4.06 kHz, and its sensitivity is 0.0279V//s.
Research on Tempering Process of LZ20Mn2 Seamless Pipe for Axle
Authors: Huang Zhong Guo , Dong Hong Lei , Yuan Qing Hua , Song Jian , Fan Jia
Published: March 2010

In order to find out the effects of tempering process on properties of axle steel, the thesis analyzes the change trend of properties of LZ20Mn2 axle steel pipe with variation of tempering temperature. And SEM was used to observe and analyze the fracture. The results show that the strength and hardness of LZ20Mn2 axle steel drop gradually and its toughness and plasticity are increased when tempering temperature goes up. Change of material properties trends to slow down after tempering at 570 °C. From point view of toughness, the technology for the best quality LZ20Mn2 axle pipe steel is the one with quenching at 880 °C with temperature holding for 30min, and tempering at 530 °C with 90min holding temperature. After heat treatment, the microstructure is fine grain size tempered sorbite structure and has good plasticity and toughness, so it can meet the requirement of both high strength and high toughness for axle.
Dynamic Analysis of Optical Brittle Crystal Slicing by Using Wiresaw
Authors: Feng Yan Bo , Sun Tao
Published: March 2010

In recent years, wire sawing is considered to be a potentially better technology of slicing brittle crystals especially semiconductor, owing to the unmatched advantages of slicing large ingot into thin wafers with high efficiency, fine quality and less kerf loss. This paper analyses the dynamic effect on wire from a variety of excitation and mechanical structure in the process of cutting on the basis of the effects of vibration on slicing wafer quality. A suitable model is built according to Hamilton principle, closed form expressions is present for the steady state response using finite element method. The relation between inherent characteristics of wiresaw and different system parameters is obtained.
Simulation and Experiment for Rigid and Flexible Wings of Flapping-Wings Microrobots
Authors: Liu Lan , He Zhao Xia
Published: March 2010

In this paper, an insect-based flapping-wing flying microrobot was built which can successfully fly in the sky. The unsteady aerodynamics associated with this microrobot was studied by using the method of computational fluid dynamics (CFD). On the basis of numerical simulation, the Fluid-Structure coupling mechanics for flexible flapping-wings were studied and discussed. According to the practically developed flapping-wing microrobot, a 2-D simulation model for flexible flapping-wings was established. Fluid-Structure coupling deformation and the effects of this model on the aero dynamic performance were analyzed, which have offered a theoretical basis for design of the aircraft with flexible flapping-wing. In order to verify the results of numerical simulation, aerodynamic performance tests have been conducted for the rigid and flexible flapping-wings in a low turbulence and low Reynolds number wind tunnel.
A Passivity-Based Approach to the Rotor Resistance Estimation and Sliding Mode Control for Induction Motors
Authors: Chen Jenn Yih , Lee Bean Yin
Published: March 2010

Based on the passivity theorem, an approach of the rotor resistance estimation and sliding mode position control for induction motor drives is proposed in this paper. Owing to values of the moment of inertia and the viscous coefficient of induction motors are generally small, the load torque disturbance is a critical term to create the chattering phenomenon. The adaptive laws are taken into account for estimating the rotor resistance and the gain of a load torque. Therefore, the chattering associated with the conventional sliding mode controller can be alleviated. The stability analysis of the estimator and the position control system is carried out by employing the passivity theorem. Finally, experimental results are presented to show the performance and robustness of the estimator and the controller with the variations of the motor mechanical parameters, rotor resistance, and load torque disturbances.
Tri-Objective Optimization in Production Based on Stochastic Principle
Authors: Hong Li , Yu Jian Jun
Published: March 2010

Tri-objective optimization of time, cost and quality is complex and valuable research hotspot which is of expansive practice application foreground. Exact method can only solve some small scale optimization problem, but the practice problem is usually large scale. In order to analyze and research the complex large scale optimization problem, the integrative optimization model of time-cost-quality is set up according to the action rules and relations of three objectives. Tri-population genetic algorithm is put forward for the optimization model based on the idea of intellective stochastic search. The algorithm adopts different populations to carry out the parallel search to realize rapid optimization. Finally the methods put forward are applied to manufacturing case of airplane part, and a series of optimization result is achieved. The case application validates the correctness of the model and the availability of the algorithm.
Dynamic Analysis on Noise and Vibration Study of Flexible Wiper Blade System
Authors: Salim Mohd Azli , Noordin A. , Zain Mohd Zarhamdy Md , Abu Bakar Abd Rahim
Published: March 2010

Chatter is one of the unwanted noise and vibration phenomenon which are generated during the wiper operation. It is a low frequency and self-excited vibration that is often generated before and after the wiper reverses its direction. This leads to a poor visibility and annoying sound to the driver and passengers. Therefore, this paper is aimed to propose a technique that can be apply to tackle this problem. Hence, an existing two-dimensional mathematical model of a wiper system available in the open literature is adopted. Firstly, the baseline model is simulated in order to observe its vibration response. Then, an input shaping control scheme is introduced into the baseline model. It is found that the input shaping control scheme can reduce the vibration level approximately by 30 percents from the baseline model.
Effects of Nb Doping on Dielectric and Ferroelectric Properties of Bi4Ti3-xNbxO12+x/2 Ceramics
Authors: Feng Xiang , Wang Hua , Huang Xiao Dan
Published: March 2010

Bi4Ti3-xNbxO12+x/2 (BNT) ceramics were prepared by a solid-state reaction method. Effects of Nb doping on dielectric and ferroelectric properties of BNT were investigated. XRD patterns show that Nb5+ substitutions do not change the phase structure. With the increase of Nb doping, dielectric constant and Curie temperature decrease gradually. At the same time, dielectric loss peaks become flatter and dielectric losses become smaller due to the decrease of oxygen vacancies derived from the introduction of Nb5+ at Ti4+ site in BNT. Remanent polarization Pr and coercive field EC of BNT ceramics are both larger than those of BIT without Nb doping. With the increase of Nb doping from 0 to 0.045, Pr increases to the largest value of 17 μC/cm2 and EC decreases to the lowest value of 87 kV/cm, but Pr will decrease when Nb doping content is over 0.045.
Effects of Mg-Doping on Structure and Electric Properties of MgxZn1-xO:Al Ceramics
Authors: Wang Hua , Huang Zhu , Xu Ji Wen , Yang Ling , Ren Ming Fang
Published: March 2010

MgxZn1-xO:Al ceramics with low resistivity using ZnO, MgO and Al2O3 nano-powders as raw materials were obtained by unpressurized sintering. The influence of Mg content on structure and electric properties of MgxZn1-xO:Al ceramics were studied. The results indicate that there is a single phase of wurtzite structure of ZnO in MgxZn1-xO:Al ceramics at x ≤ 0.3, and when the value of x was 0.3, phase separation was observed. The grains become smaller and more homogeneous with increasing Mg content to above 0.3. The resistivity of MgxZn1-xO:Al ceramics obviously increases with increasing Mg concentration due to the decrease of the carrier concentration and the mobility deriving from the decrease of Al-doping efficiency. The electrical conduction of MgxZn1-xO:Al ceramics can be markedly improved by increasing the Al-doping level and the lowest resistivity of 8.3×10-4Ω•cm can be obtained when Mg/(Mg+Zn)=0.2 and Al/(Mg+Zn+Al)=0.03.
Frequency Equations of Magneto-Thermoviscoelastic Surface Wave
Authors: Xu Hong Yu , Xue Bing Bing , Fu Zhu Mu
Published: March 2010

The model of the generalized linear micropolar magneto-thermoviscoelastic theory is presented in this paper. It can be applied to the coupled theory as well as to five generalizations, such as L-S theory, G-L theory, H-I theory, G-N theory of type (II) and C-T theory. If some parameters in this model are taken as given values, we can easily deduce the known models of Kelvin-Voigt model and other generalized micropolar/magneto/thermo/viscoelastic theory model. The magneto-thermo- viscoelastic waves at an interface between two micropolar viscoelastic solid mediums are discussed with the model. Using continuous conditions, the general frequency equations are obtained. Also as a validation, if one media is replaced by vacuum, we have deduced the frequency equation of Rayleigh wave. And if the problem is reduced to elastic case, it coincides with the results of Ewing et al.
Creep Behavior of an AZ91 Magnesium Alloy Reinforced with Aluminum Silicate Short Fibers
Authors: Tian Jun , Li Wen Fang , Han Li Fa , Peng Ji Hua
Published: March 2010

Constant stress tensile creep tests were conducted on an AZ 91–25 vol.% aluminum silicate short fiber composite and on an unreinforced AZ 91 matrix alloy. The creep resistance of the composite is shown to be considerably improved compared with the matrix alloy, and the resistance effect is better with the increase of temperature. The steady-state creep rate of the composite is 4.54% of matrix alloy at 473K, and 2.56% of matrix alloy at 573K. The creep strengthening arises mainly from the effective load transfer between plastic flow in the matrix and the fibers. Microstructural investigations by SEM revealed good fiber–matrix interface bonding during creep exposure. Short fibers have a great function in load bearing and transmission load, and greatly hinder the dislocation movement, thus enhancing the creep resistance of the composite. The creep mechanism of the composite is dislocation and grain boundary sliding control.
The Characteristics of the Magnetic Memory Signals under Different States for Q235 Defect Samples
Authors: Li Jian Wei , Xu Min Qiang , Leng Jian Cheng , Xu Ming Xiu
Published: March 2010

Magnetic behavior of ferromagnetic materials has been using to detect defects of materials. To evaluate the stress states of the components by the magnetic memory signal, Q235 defect asymmetrical samples were made. The characteristics of magnetic memory of Q235 have been studied in the three different testing environments which are online-loading, online-unloading and offline-unloading under cycle tensile stress. The results show that magnetic memory signals have different characteristics in different testing environment. It is feasible to evaluate preliminarily the stress state by the magnetic memory signals.
Effect of Silica Sol on the Properties of Unfired Mullite Rollers
Authors: Huang Kai , Li Yuan Bing , Feng Bing , Wu Qing Shun , Yang Li , Xiao Ling
Published: March 2010

An unfired mullite roller was produced by using mullite roller waste, white fused alumina, α-Al2O3, clay and micro silica, meanwhile silica sol was used to partially substitute for micro silica as the SiO2 source. The effect of silica sol on the properties of unfired mullite roller was investigated. The results showed that the microstructure and properties of the unfired mullite roller prepared with silica sol were improved. With the increase of silica sol, the COMR, bulk density and thermal shock resistance increased, and the water absorption rate decreased. When silica sol was 8w/t%, treated temperature was 1200°C, the CMOR of unfired mullite roller was more than 50MPa.
Mutual Interaction of Two Rail Surface Cracks under Thermo-Mechanical Contact Loading
Authors: Guo Jun , Li Wei , Wen Ze Feng , Jin Xue Song
Published: March 2010

A finite element analysis is conducted to study the mutual interaction of two oblique surface cracks in rail under the wheel-rail full slip contact loading and frictional heating. In the present thermo-mechanical coupling finite element model, the heat-convection between the rail and ambient, heat transfer between the crack surfaces, and temperature-dependent material properties are taken into consideration. The variation of stress intensity factors with the distance between two cracks is investigated. The results reveal that the stress intensity factor K1 increases with an increase of the distance between the cracks. The effect of the distance between the cracks on the stress intensity factor range K2 is not significant.
Strain-Induced Precipitation in Nb-Bearing Low Carbon Multi-Microalloyed Steel
Authors: Yuan Shao Qiang , Liang Guo Li , Zhang Xiao Juan
Published: March 2010

Thermo-simulation test, transmission electron microscopy(TEM) and nanobeam EDS technique were used to investigate the strain induced precipitation behavior during relaxation process after deformed austenite in Mn-Mo-Nb-B low carbon multi-microalloyed Steel. The experiment results indicate that during isothermal held at 850 °Cand 900 °C after predeformation, the size of precipitates occurred in the Mn-Mo-Nb-B steel at different stage is smaller than that happened in the only Nb and Ti-bearing microalloyed steel. The ratio of Nb/Ti to precipitates increased with the relaxing time. After being held longer, Mo atoms would enter the lattice of (Nb,Ti)(C,N) precipitates and the amount in the precipitates increased with the relaxation as time prolonged.
Influence of Plastic Deformation Degree on Microstructure and Mechanical Properties of the Magnesium Alloy ZK60 after T5 Treatment
Authors: Yu J.M. , Zhang Zhi Min , Zhang Bao Hong , Wang Qiang
Published: March 2010

The effects of extrusion ratios (15, 30, 45and 60) on microstructure and mechanical properties of ZK60 magnesium alloy after T5 treatment were investigated. The results show that mechanical properties increase with the increase of extrusion ratios from 15 to 45．However, when the extrusion ratio is increase to 60, each mechanical property is decreased severly．By comparison，in the extrusion ratio of 30, ZK60 magnesium alloy after T5 treatment has excellent comprehensive mechanical properties．Different degrees of dynamic recrystallization appeared in the extrusion process and induced precipitation of second phase．The precipitation of the second phase is beneficial to the grain refinement and meanwhile to the promotion of the strength．
Simulation and Analysis during Conveyor Stop Process Based on AMESim
Authors: Li Guang Bu , Li Da Zhi , Li Ru Qiong
Published: March 2010

This paper builds drive system model of belt conveyor during three kinds of stop process based on AMESim, and deduces belt tension equations. A case study on a long belt conveyor dynamic performance concludes that the braking stop process is shortest and motor stop process is longest. Also, the torque change rules of drive pulley among three kinds of stop process are same, that is increase at the beginning and decrease at last. The displacement of gravity take-up is largest during motor stop process, and the gravity moves far from the original point during power-off stop process.
Influence of Surface Friction Mismatch on Front End Bending during Plate Rolling
Authors: Pang Yu Hua , Hu Yang Lei , Sun Qi , Liu Chang Rui
Published: March 2010

Asymmetrical conditions that occur during plate rolling can cause front end bending or lead to poor product shape, profile, quality and cause reduced productivity. In these investigations, a model of calculating curvature is deduced according to the theory of rolling, which has been used to determine the effect of surface friction mismatch on the direction and severity of curvature in plate rolling. Results show that the front end bending can occur easily due to the mismatch of coefficient of friction. Moreover, the results have identified that the bending inclination of large reduction, large radius of roll and thin rolling stock is higher than that of the reverse, the bending inclination of the entrance thickness of rolling stock is higher than that of the reduction, and the bending inclination of the reduction is higher than that of the radius of roll.
Effect of Thinckness on Residual Stress Fields of Cold Expansion Hole
Authors: Liu Yong Shou , Gou Bing Wang , Shao X.J. , Jiang Zhi Feng , Yue Z.F.
Published: March 2010

In this paper, four axisymmetrical finite element models have been established to study effect of thinckness on residual stress fields of cold expansion hole, experiments were carried out to measure the residual stress of cold expansion hole and verify simulation results. The experiment results also show that cold expansion processing can decrease surface roughness of holes and improve surface quality. The FEM results show, at the top(bottom) surface, the volue of the radial residual stress varies with the plate’s thickness, and the regularities of distribution of the radial residual stress are identical. The volue and the regularities of distribution of the circumferential residual stress vary with the plate’s thickness. At the mid-thickness surface, the volue and the regularities of distribution of radial residual stress vary with the plate’s thickness. The volue of the circumferential residual stress varies with the plate’s thickness, and the regularities of distribution of the radial residual stress are identical.
Effect of Severe Plastic Deformation Technique on the Dissolution of θ’ Phase in Al-Cu Binary Alloy
Authors: Ning Ai Lin , Peng Bei Shan , Huang Wen Jie , Liu Zhi Yi
Published: March 2010

The effect of severe plastic deformation method on the dissolution of θ’phase in Al-Cu binary alloy was investigated by employing equal channel angular pressing(ECAP) and multi-axial compression(MAC). The results suggested that a more rapid dissolution of θ’ phase occurred in the MAC processed sample comparing with the ECAP processed sample, which was attributed to the stress state difference between ECAP and MAC processed samples .
Abnormal Changes of the Rheological Property of Sn Melt Induced by Temperature
Authors: Yang Zhong Xi , Geng Hao Ran , Zhang Ning
Published: March 2010

Rheological behaviors of Sn melt were systematically studied using a comprehensive measurement instrument designed in our lab. Structure of the Sn melt was analyzed by a liquid XRD technology. The result indicates that in the vicinity of 400°C, 800°C and 1200°C, the melt is a non-Newtonian fluid, while it is a Newtonian fluid within the temperature ranges of 400—800°C, 800—1200°C and over 1200°C. It is evidenced that the rheological property of the Sn melt is correlated to the changes in the melt structure. When the temperature is raised, the correlation radius rc, the coordination number Ns decreases, while in the vicinity of 400°C and 800°C, the correlation radius rc and the coordination number Ns of the Sn melt all show discontinuous changes.
A Novel Poly(Ferrocenyl-Schiff Base) and its Charge Transfer Complex with Iodine
Authors: Xiong Guo Xuan , Huang Hai Qing , Yang Chuo
Published: March 2010

A ferrocenyl Schiff base monomer was synthesized through the condensation of ferrocenecarboxaldehyde and phenylenediamine under neutral conditions, and then been used to produce copolymer materials with terephthaloyl chloride monomer by the Friedel-Crafts method. The model compound and copolymer of a novel poly(ferrocene-Schiff base) and their charge transfer complex with iodine was successful obtained, their structures been characterized by 1H-NMR spectra, infrared spectra, and ultraviolet spectra. In addition, the effects of iodine doping degree on its structure was studied, the electrical measurement results showed its conductivity can be increased several orders of magnitude after doping with iodine, the maximum conductivity at room temperature is 3.17×10-4 S•cm-1.
Investigation of Nonequilibrium Dynamics of Nickel Film Excitated by Femtosecond Laser
Authors: Ren Nai Fei , Jin Wei Feng
Published: March 2010

Using femtosecond laser pump-probe technique, the transient change in nickel film reflectivity after excitation by femtosecond laser pulse was measured, which indicated the thermalization process of the nickel film. A novel mechanism of the themalization process of the nickel film was proposed to interpret experimental results. It is found that the trend of the transient reflectivity change and the temperature change of nickel film excitated by femtosecond laser pulse are attributed to the special energy gap of the nickel film.
Effect of Specimen Dimensions in Dynamic Torsion Testing
Authors: Shu Dong Wei , Ahmad Iram Raza
Published: March 2010

The effect of specimen’s mean radius to average wall-thickness ratio rs/t, has been studied using the Split Hopkinson Torsional Bar. The rs/t ratio was varied between 6.5 and 39 keeping the outer diameter and the gauge length of the specimen constant. Higher strain rates and strains are observed for specimens with larger specimen radius to wall-thickness ratio rs/t. However no monotonic trend of the shear stress with rs/t variation is found. A sharp decrease in the torsional stiffness of the specimen is observed with increasing the specimen’s rs/t ratio. The rs/t ratio can also be used as a useful dimension to enhance the strain rate in tubular specimens.
Research on Initial Discontinuity State of an Advanced Aluminum Alloy Rolling Alclad Sheet
Authors: Tan Xiao Ming , Zhang Dan Feng , Liu Zhi Guo
Published: March 2010

Initial Discontinuity State is the characteristic of aluminum alloy, it is a random parameter. According to an advanced aluminum alloy rolling alclad sheet, the coupons were carried out tension and fatigue test, stress ratio R=0.06, 0.2, 0.5 and the maximum stress level σmax=403, 370, 330, 310, 280, 260, 240, 220MPa through Material Test System 810. By use of scanning electron microscope, the tension and fatigue fracture surface was analyzed and the flaw size was obtained. The metallographic coupons were prepared, the constituent particles were surveyed using KH-7700 optical microscope and particulate size was gained. Based on measuring data, different distributions (Normal, Lognormal, Weibull, Logistic, Gumbel) were verified, the best-fit distributions of tension and fatigue facture flaw size is Lognormal distribution, as same as that of θ phase. However, that of S phase size is Weibull distribution.
Dynamic Properties of Asphalt Binders Containing Fiber Modifiers
Authors: Ye Qun Shan , Wu Shao Peng
Published: March 2010

Dynamic shear test and creep shear test were employed to investigate the dynamic properties of various fiber modified asphalt binders with the fiber content of 1.0%. The test results indicate that complex shear modulus of asphalt binders containing fibers are increased while the phase angles are decreased greatly, which implies that the asphalt binder is reinforced by the addition of fibers and the elastic property of asphalt binder is improved significantly, especially at high frequency levels. The total strain during loading period and the residual strain after the creep shear test of asphalt binders are reduced greatly by the addition of fibers. Furthermore, the creep modulus of fiber modified asphalt binders is increased and the development rate versus loading time of creep modulus is decreased.
Design and Characterization of Ultrahigh Strength Dual-Phase Steel with Low Ratio of Yield Strength/Ultimate Tensile Strength
Authors: Liao Xin Sheng , Wang Xiao Dong , Li Xu Fei , Guo Zheng Hong , Rong Yong Hua
Published: March 2010

An ultrahigh strength dual-phase (DP) steel with low ratio of yield strength/ultimate tensile strength (YS/UTS) was designed based on the simulation using JmatPro software so as to improve formability as well as to extend its application in automobile industry. Results show the DP steel suffered from water quenching (WQ) technology exhibits high ratio, 0.872, of YS/UTS, which loses the advantage of formability of DP steels and restricts its application in automobile industry. Therefore, the controlled slow-cooling rate (CSCR) technology is employed to this DP steel, and the low ratio, 0.458, of YS/UTS is obtained. Although the tensile strengths of the DP steel suffered from two kinds of technologies are over 1000 MPa, The YS of the DP steel with CSCR technology is 480 MPa and is much lower than 983MPa of the DP steel with WQ technology, which are attributed to relative large grains and small volume fraction of martensite in the former based on the characterization of microstructure by optical microscope, scanning electron microscope, transmission electron microscope and electron backscattering diffraction.
The Skin Effect in a High Pressure Die Cast Mg-9%Al Alloy
Authors: Yang K. , Nagasekhar A.V. , Caceres C.H.
Published: March 2010

Cross sectional microhardness maps of cast-to-shape tensile specimens of rectangular and circular cross-sections have been obtained for a Mg-9 mass% Al alloy. The hardness is generally higher near the surface and at the corners of the cross-section in comparison with that at the centre. The lower hardness values at the casting core are accounted for by the coarser solidification microstructure and the concentration of porosity. The cross sectional mapping shows that the harder surface layer is generally uneven, questioning the concept of a well defined, uniform and continuous skin. Physical reasons for these features of the casting’s skin are discussed in terms of the grain microstructure.
Research on Evaluation of Corrosion Grade Based on Image Processing Technique
Authors: Zhu Zuo Tao , Mu Zhi Tao , Chen Ding Hai , Su Wei Guo
Published: March 2010

The corrosion images of LY12CZ aluminum alloy with different corrosion time were obtained from accelerated corrosion experiment. The changing law of pits corrosion ratio at different corrosion time and corresponding corrosion grade were attained through image processing technique based on binary characteristic extraction. A new thought of corrosion damage evolvement law for aluminum alloy was proposed based on Corrosion grade which was regarded as the evaluation standard of corrosion damage for aluminum alloy.
Effects of Secondary Dendrite Arm Spacing on Microporosity of A357 Alloy
Authors: Zou Yong Zhi , Xu Zheng Bin , Zeng Jian Min
Published: March 2010

Microporosity in cast aluminum alloys formed during solidification of castings can be due to the evolution of dissolved hydrogen gas from the liquid metal, the inability of liquid metal to feed through interdendritic channels, or a combination of both. The secondary dendrite arm spacing (SDAS) of the casting may affect either the evolution of hydrogen gas or the ability of feeding. In this investigation, a method based on the Nearest-Neighbor-Distance (NND for short) cluster analysis of image analysis data was used for distinguishing the gas and shrinkage pores in A357 alloy, in order to study the effects of SDAS on the microporosity formation. It shows that the shrinkage pores are prone to form in the specimens with small SDAS. The discrete, isolated gas microporosity is prone to form in the specimens with large SDAS.
Thermal Aging Embrittlement Evaluation of Nuclear Primary Pipe Steel by Ductile to Brittle Transition Test
Authors: Xue Fei , Yu Wei Wei , Wang Zhao Xi , Shu Guo Gang , Wang Xi Tao , Jiang Jia Wang
Published: March 2010

In order to determine the ductile to brittle transition behavior of nuclear primary pipe material (Z3CN20.09M) during the thermal aging procedure, instrumented impact tests at different temperatures were performed on Z3CN20.09M aged at 400°C for up to 3000 hours. The load-deflection curves from the instrumented impact tests described both the loading and the fracture stages, from which the dynamic strengths and energy were calculated. The results indicated that the thermal aging decreases the impact energy and shifts the ductile-to-brittle transition curves to higher temperatures.
Strip Shape Analysis of Asymmetrical Cold Rolling of Thin Strip
Authors: Jiang Zheng Yi , Du Xiao Zhong , Du Yan Bing , Wei Dong Bin , Hay Matthew
Published: March 2010

Strip shape control during cold rolling of thin strip is a challenge in rolling practice. In the paper, finite element model of strip shape during cold rolling of thin strip in asymmetrical rolling case was successfully developed, and the strip shape such as the thickness distribution along the strip width have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape in practice.
Effect of Welding Method on Weld Defects of ADB610 Steel
Authors: Zhang Tian Hui , Liu Wen Min , Xu Ren Ping , Xu Bin
Published: March 2010

Statistical analysis was carried on weld defects of low carbon bainite ADB610 steel using shielded metal arc welding (SMAW) and mixed active-gas arc welding (MAG). By Pareto diagram analysis, although the ratio of porosity air hole using SMAW is slightly higher than the one using MAG, there is no qualitative difference in ADB610 steel weld defect types between two welding methods. And the crack occurs seldom, which indicates ADB610 steel has lower crack-sensitivity using SMAW and MAG. By histogram analysis and rank test, it can be concluded that there is distinctive difference in defect size between SMAW and MAG, and the average size using SMAW is bigger than the one using MAG. So if possible, MAG is recommended for low carbon bainite ADB610 steel.
Effects of Coating on Interfacial Fatigue of Fiber-Reinforced Composites
Authors: Chen Yan Hua , Chu Jian Yu , Zhu Qing Jie
Published: March 2010

Coating is one of important parts in fiber-reinforced composite. Under cyclic loading, the effect of coating on interfacial fatigue is investigated based on double shear-lag model. Stresses of components are obtained. Relationship for analyzing interfacial debonding is established by the Paris Formula. Interfacial fatigue on fiber/coating and coating/matrix is simulated. It can be seen that interfacial debonding on different interfaces meet energy conservation law in general.
Experimental Research on Coaxial Extrusion of GF/Pb Complex Wire
Authors: Tang Jing Lin , Li Xia , Wang Li Wei
Published: March 2010

GF/Pb Complex Wire, as the key, characteristic component of a high-energy battery, is difficult to produce continuously for the fiberglass core’s liability to rupture in extruding. The research works, presented in this paper, show that this complex wire of brittle core can be successfully formed by the continuous side-way coaxial extrusion, using the die set specially designed, at a relative lower temperature and with a stable wire puling force.
Strain-Based Fatigue Test and Reliability Research of 42CrMo Alloy Steel
Authors: Xu Nan , Ren Xiu Hua , Wang Wei Qiang
Published: March 2010

The strain-based fatigue tests of 42CrMo alloy steel were conducted by controlling six sets of total strain range, and stress range data was obtained under each strain range. The results of fatigue test revealed that fatigue performance of 42CrMo alloy steel was of tremendous dispersivity all though materials were strictly chosen, heat-treated and machined. Cyclic stress-strain (CSS) curves were compared with monotonic tensile curve, which showed that 42CrMo alloy steel quenched and tempered was a kind of cyclic softening material. Evaluation results revealed that LND was the best probability function to describe cyclic stress of strain fatigue for 42CrMo steel. Cyclic stress range under the median and high probability was evaluated by means of stochastic performance probability models.
A New Electromechanical Coupling Model for Piezoelectric Actuator
Authors: Zhao Zeng Hui , Wang Yu Ping , Zhao Xiang Dong , Yuan Yi Kun
Published: March 2010

Combining the constitutive equation of piezoelectric ceramic with elastic-dynamical equations and coupling theory of FEM, the finite element control equation for piezoelectric actuator is established. Detailed calculation of the electro-mechanical coupling field parameters is made by the SP1 type longitudinal-bending vibrator and results show it can be used for the transparent calculation for piezoelectric intellectual structure and avoid the black box operation in FEM software. The model lays the foundation to develop the special program for piezoelectric actuator and to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power.
Numerical Simulation of Push-Bending Process of Aluminum Section Profile
Authors: Sun Zhen Zhong , Chen Sheng Gui , Jing Ye
Published: March 2010

The aluminum profile can be formed into a complicated part such as 360º abnormity section circle parts that is difficult to be manufactured by other techniques. A new bending method was proposed for bending process. The push-bending principle, deformation procedure, curvature spring-back, section distortion and wrinkling are studied numerically. All cross-sections for the profile are provided a rather homogenous deformation degree. The curvature value of component and the distortion of section keep high consistence in push-bending process. The wrinkling tendency is reduced with increasing relative cross section thickness t/H and die radius R. The numerical model represents the observed response in the laboratory tests fairly well.
The Analysis of the Distribution of the Failure Statistical Data Hydrogen-Adjacent Pipelines
Authors: Liu Chang Hong , Liu Xin Tian , Wang Ren Liang , Zhao Li Hui , Huang Hu
Published: March 2010

In reliability design and maintenance plan, determining statistical distribution type of interrelated structure is a very important job, and it is always determined through reliability test, which are time-consuming and needs a large number of tests. In this paper, a method determining statistical distribution function was proposed through the experimental data of the Creep Behavior. This method uses the test data; the results of Larson-Miller Method obtained from the data from experiments, and use the least-squares linear regression to get the parameter of common probability distribution function, such as Weibull Distribution, Lognormal Distribution and Normal Distribution. Statistical function of structural failure data was derived through discussion and comparison of results from various methods. The examples proved the validity and usability of this method.
The Thermal Characteristics of Invar 36 Alloy during Plane Grinding
Authors: Qiao Y.P. , Kang Ren Ke , Jin Zhu Ji , Gao Hang
Published: March 2010

Invar 36 alloy is widely used in the field of precision manufacturing owing to its minimal thermal expansion coefficient. Grinding is very important in Invar surface processing, and the thermal characteristics is a key factor to affect the residual stress and deformation of grinding. In this paper, the thermal characteristics of Invar 36 alloy during plane grinding was tested. The thermal characteristics of Invar 36 alloy was found to be between carbon steel and nickel-based superalloy. The lower grinding temperature and better ground surface with lower residual stress can be obtained by using the reasonable grinding parameters.
Moving Crack in an Infinite Plate of Orthotropic Anisotropy FGMs under Anti-Plane Shear
Authors: Bi Xian Shun , Yang Feng , Ma Shuang Shuang
Published: March 2010

The moving crack problem in an infinite plate of orthotropic anisotropy functionally graded materials (FGMs) subjected to an anti-plane shear loading is studied by making use of non- local theory. The shear modulus and mass density of FGMs are assumed to be of exponential form. Fourier transform is employed to solve the partial differential equation. The mixed boundary value problem is reduced to a pair dual integral equations which is solved by using Schmidt’s method. The semi-analytic solution of crack-tip stress is obtained, contrary to the classical elasticity solution, the crack-tip stress fields does not retains the stress singularity. The influences of the characteristic length, graded parameter, orthotropic coefficient and crack velocity on the crack-tip stress are analyzed. The numerical results show that the stress at the crack tip decrease as the characteristic length, crack velocity, graded parameter are increased and increase as the orthotropic coefficient is increased.
Stress Distribution in a Piezoelectric Material with an Elliptical Hole Subjected to Remote Uniform Shear Mechanical and Electric Loads
Authors: Zhou Min Juan , Duan Shi Jie , Kong Yan Ping , Liu Shu Hong
Published: March 2010

A two-dimensional electro-elastic analysis is performed on a transversely isotropic piezoelectric material with an elliptical hole, which is subjected to remote uniform shear forces, and remote electric field. Based on the impermeable electric boundary conditions, close form solutions are obtained by using the complex potentials method. Taking PZT-4 ceramic into consideration, the stress distributions around the neighborhood of the elliptical hole are given. It is shown that the hole geometry and the electric field are responsible for the shielding effect, there are sharp stress concentration near the hole.
Microstructure Formation at Low Velocity during Directional Solidification of Pb-Bi Peritectic Alloys
Authors: Hu Xiao Wu , Li Shuang Ming , Gao Si Feng , Liu Lin , Fu Heng Zhi
Published: March 2010

Directional solidification experiments on Pb-Bi peritectic alloys have been conducted at very low velocity (V=0.5 μm/s) and high thermal gradient (G=25 K/mm). Incomplete banded and oscillatory structures have been observed in both of hypoperitectic and hyperperitectic compositions over several millimeters of growth. These structures resulted from the repeated nucleation and competition between properitectic α- and peritectic β-phases. The banded or oscillatory structures are found to be transient and the final steady-state phase was only the peritectic β-phases. With an increase in composition, β phase formed and α phase disappeared at a lower solidified distance. Composition variations in the banded structure are measured to determine the solute distribution along the growth direction.
The Effect of Al-5Ti-1B and Combination Electromagnetic Field on Grain Evolution of Die Casting Commercial Aluminum
Authors: Zhu Qing Feng , Zhao Zhi Hao , Wang Xiang Jie , Cui Jian Zhong
Published: March 2010

The effect of increasing the amount of added grain refiner and combination electromagnetic filed on grain size and morphology has been investigated by die casting of commercial aluminum. The results show the grain size and the grain morphology both are transited with the increasing of the addition of Al-5Ti-B. The grain size continuously decreased with increasing the addition of grain refiner. Without grain refiner additions, an obvious transition in grain size and morphology is observed with the application of low frequency electromagnetic field (LFES). The efficiency in grain refinement of LFES decreases with increasing the amount of grain refiner. However, even when the addition of grain refiner is 2 wt. % Al-5Ti-B, 63 % grain size reduction still is observed by the affect of LFES. This result shows that the LFES can enhance the efficiency in grain refinement of grain refiner.
A New Compound Phosphate Heat-Cured Foundry Binder
Authors: Xia Lu , Zhang You Shou , Huang Jin
Published: March 2010

Influences of additives on the physicochemical characteristics and technologies of binder are researched, and a new compound phosphate heat-cured foundry binder coded B8M15 is developed. The binder is made from environmental friendly inorganic materials such as phosphoric acid, aluminum hydroxide, B-ion additive and Mg-ion additive. Laboratory results indicate that combined effect of B-ion additive and Mg-ion additive can improve the storage stability of the binder and its sand mold or core, as well as they can increase the dry strength of its sand mold or core from 0.77MPa to 2.51MPa. This binder has low gas evolution and good collapsibility.