bluuebunny/crossref_metadata_2025 huggingface dataset:
LEFM-Based Fatigue Life Assessment of Anthropogenic CO2 Pipeline under Inner Pressure Fluctuation
Authors: Jin Qiao , Li Bing , Wen Quan
Published: June 2012

Natural or anthropogenic CO2pipelines have been in operation in USA, Europe and North Africa for almost three decades, which are aimed at implementing EOR(enhanced oil recovery) technology and (more importantly) developing CCS(carbon capture and storage) technology. At present, there is no specific pipe standard for CO2transportation pipelines. Instead, oil & gas pipeline system is directly introduced into the field of CO2transportation piping. Therefore, the technical details for oil & gas pipelines transporting supercritical CO2should be carefully taken into consideration due to the relevant effects of different impurities in the transported CO2and the different transportation environment for these two mediums, i.e. oil&gas mixture and CO2. For the application of anthropogenic CO2pipe transportation technique, this paper will address a FE-based method which can evaluate fatigue life of a supercritical CO2 transmission pipeline containing an inner crack. Specifically, a portion of welded round steel pipeline is selected as the object of our analysis. And under the inner pressure fluctuation scenarios, an FRANC2D finite element procedure is generated to simulate mode-I crack extension from a given inner edge crack and to calculate the corresponding stress intension factors(SIFs) varied with different cracking depths. Afterwards, considering the effects of crack closure, the Paris equation is modified to build an integral analysis method for the fatigue life evaluation of CO2pipeline. Thus, the relation between the fatigue life and the inner pressure fluctuation range can be determined by performing the proposed fatigue crack growth analysis, which can also provide a LEFM-based pipeline selection method in terms of fatigue durability other than the conventional method coming from the structural strength theory.
Fracture Mechanism of Aluminum Joint Brazed by Zn-Al Alloy
Authors: Zhang Man , Jiang Hai Lin , Xu Hong Bin , Lin Yue Bin
Published: June 2012

Zn-Al alloy microstructures were investigated, moreover, the strength and microstructures of pure aluminium brazed joint had been studied. Joint fracture mechanism was analyzed. The results indicate that the blocky microstructure in the cast 85Zn-15Al filler metal is granular and fine. Accordingly, the blocky eutectoid structure in the joint brazed by 85Zn-15Al is fine and even. Stress concentration emerges difficultly between fine blocky eutectoid structure and its surrounding structure. So the joint strength is highest. When Al content in the Zn-Al alloy exceeds 15wt.%, the blocky eutectoid structure become large in the cast filler metal and the brazed joint. The brazed joint strength decreases.
Shear Lag Effect of Continuous Curved Box Girder with Initial Curvature
Authors: Wu You Ming , Lu Yong Jun , Shi Han
Published: June 2012

The homogeneous solutions of the governing differential equations for shear lag are used as the displacement patterns of the finite segment are presented. A finite segment model with consideration of initial curvature, bending, torsion and shear lag is established. In addition, the tests of the two-span continuous curved box girder and numerical calculations of the model tests by finite segment method and finite element method are made. The results of the model tests and numerical calculation are consistent with each other. An actual example was given to investigate the shear lag effect of a continuous curved box girder under load. The research results show that the initial curvature has an obvious influence on the shear lag effect of a continuous curved box girder.
Estimation Model for Fatigue Life of Pipeline Steel with Mechanical Damage
Authors: Jiang Yu Rong , Chen Mei Bao
Published: June 2012

It is impossible to keep pipelines free from mechanical damage in the manufacturing, installation and servicing processes. In this paper, the geometric model for fatigue life of pipeline steel was introduced. The local plastic deformation was considered to imitate the mechanical damage on the pipe. The estimation models of the fatigue crack initiation life and the fatigue crack propagation life were proposed according to the plastic deformation. The result is expected to be beneficial to the understanding of the effect of damage on the safety of pipelines and fatigue life prediction.
The Effective Measures of Preventing Collapse Angle Problem in Polishing Plastic Mould
Authors: Ren Yi Lei , Lin Hong Qi
Published: June 2012

Plastic mold polished, in the mold cavity parting collapsed throwing angle appear, which seriously affect the dimensional accuracy and surface quality of the plastic parts, this article proposed two effective preventive measures: (1) cutting the model which having a same size as plastic model of the cavity at the parting surface, sticking the model and cavity parting with 502 glue together, within the required type of alignment, and then thrown together, polished finish will be a model to out; (2) in the plastic model cavity machining process, type in the mold cavity surface set aside allowance 0.5 ~ 1mm, polished until the cavity is completed, the surface of the cavity type 0.5 ~ 1mm rubbed off with a grinding allowance, it will ensure the cavity size and cavity to prevent the collapse of sub-surface angle at the phenomenon.
Mathematical Model of Hot Deformation Resistance of X120 Pipeline Steel
Authors: Zheng Hong Wei , Tang Di , Wu Hui Bin , Yang Liu
Published: June 2012

The high-temperature deformation resistance of X120 pipeline steel was studied under different deformation temperature and different deformation rate through the hot compression test on the Gleeble-3500 thermal/mechanics simulation test machine. The influence of deformation degree, deformation temperature and deformation rate on deformation resistance was thoroughly investigated. The deformation resistance of X120 pipeline steel increased slowly when deformation degree was higher than 0.2. With the increase of deformation temperature, the work-hardening effect was weakened, so the deformation resistance decreased. And the deformation rate had dual influences on the deformation resistance, including the effect of temperature and time. Based on the experiment data, the parameters in the mathematical model were regressed by using SPSS (Statistic Package for Social Science), and the mathematical model of the deformation resistance of X120 pipeline steel was established finally. Through the regression analysis, the model had been proved to have great matching precision.
A Solution for the Prediction of Springback in Age-Forming Strip
Authors: Xiong Wei , Gan Zhong
Published: June 2012

Creep age forming (CAF) is an effective process to manufacture aircraft panels with better performance including improved strength and toughness, lower weight and increased resistance to fatigue and corrosion. Due to restrictions of aging cycle to create the desired property, springback in CAF is larger than other forming processes. That makes its prediction one of the key technologies in CAF. A solution is developed to predict springback in CAF of aluminium components. The studies are mainly concentrated on the pure bending of aluminium strips. Comparisons of predictions with experimental data yield agreement. Effects of T-beam’s structural factors, like width, skin thickness, rib width and transitional radius on springback are investigated. And a relationship between geometrical data and springback is given by the proposed algorithm.
Grey Clustering Analysis of the Bending Creasing and Draping Properties of Bamboo Pulp/Cotton Interwoven Fabric
Authors: Ma Shun Bin
Published: June 2012

The properties of fifteen bamboo/cotton interwoven fabrics with different specifications were tested, such as static drape coefficient, dynamic drape coefficient, total bending rigidity, elastic modulus of bending, the angle of fast-elastic recovery, the angle of delayed-elastic recovery,etc. then the author taked these properties index as clustering index, fifteen bamboo/cotton interwoven fabrics as clustering object, using the grey clustering analysis to evaluate the bending, creasing and draping properties synthetically. The results show that: The first grey type included 1#, 2#, 3#, 4#, 7#, 8#, 10#, 11#, achieved optimal standard；The second grey type included 5#, 6#, 9#, achieved good standard；The third grey type included 12#, 13#, 14#, 15#, their bending properties, creasing properties and draping properties were poor.
Formation of Two-Layer Heat-Resistant Coatings on TC11 Alloy by Electro-Spark Alloying Method
Authors: Dolgiy Zakhar O. , Shao Wen Zhu , Kozyr Arcadiy V. , Martynov Sergey V.
Published: June 2012

Electro-spark alloying (ESA) method was used to create a coating on the surface of TC11 alloy (Ti–6.5Al–3.5Mo–1.5Zr-0.3Si wt%). The oxidation behavior of the TC11 alloy and its deposited coating was investigated in air at 700°C. The resulting structures were analyzed in great detail by metallographic analysis and by scanning electron microscopy (SEM)
Study on the Crack Extension Properties under Ultrasonic Vibration Uniaxial Tensile Load
Authors: Cheng Xue Li , Tian Chang Liu
Published: June 2012

In this paper, the ultrasonic vibration uniaxial tension experiment was carried out on the 20# steel with a set of ultra-high-frequency vibration device. It showed that the material defect was the important factors of ultrasonic “soften” mechanism and obtained the crack extension mechanism under ultrasonic fatigue loading, there were：(1)The high frequency vibration of the ultrasonic fatigue loading weakened the influence of the plastic zone of the crack tip and residual stress on crack extension; (2)When the fatigue crack extension, the ultrasonic wave spread in the specimen, and reflected in the crack surface, resulting the crack closure effect decreased, the plastic zone of the crack tip decreasing; (3)The high vibration frequency and deformation velocity resulted the increase of the thermal effect, crack extension energy spread to the continuous medium in the form of heat, promoting crack extension and releasing energy. It also study the influence of different groove depth and groove curvature on the material ultrasound fatigue limit, and obtained the relation curve of fatigue limit with groove depth and groove curvature.
Mechanics Analysis of Reinforcing Rib Structure in Aluminum Heating-Plate Automatic Casting System
Authors: Gong Man Feng , Li Zhong , Dong Jue
Published: June 2012

Reinforcing rib structure in the aluminum heating-plate automatic casting system was modeled by ANSYS, the static and dynamical problems were studied. Deformation and stress were calculated by static analysis, the front ten orders inherent frequency, critical rotating-speed and vibration modes were analyzed by modal analysis technology, vibration amplitude responses were obtained by harmonic response analysis. The maximum deformation value of reinforcing rib structure was less than 2mm (irrespective of the structure self-weight); the maximum equivalent stress was about 64.8MPa. It showed that the reinforcing rib structure could effectively avoid the resonance region, and the maximum vibration mode according to its inherent frequency appeared at the edge of the structure, some vibration modes were orthogonal, the main vibration modes appeared in the forms of bending, torsion, but the stretching vibration mode was scarce. The low orders inherent frequency greatly effected more than the high orders inherent frequency by harmonic response analysis, and the maximum deformation value was 25μm in low order vibrations. The conclusion is that the reinforcing rib structure fulfills design requirements and operates softly.
A Study of Hydraulic Jet Fracturing in Shallow Reservoir
Authors: Nie Cui Ping , Dai Xu Chao , Ning Chuang
Published: June 2012

The C6 reservoir of YC formation is shallowly buried in QiLiCun oilfield, Ordos basin. It’s a layered, ultra-low permeable and low pressure oil pool with poor productivity. Hydraulic fracturing is the necessary and only effective stimulation way for economic oil production. There are several calcareous interbeds in it, the thin and heterogeneous oil-bearing layers here are poorly connected or even unconnected in vertical. And it is prone to forming artificially horizontal hydraulic fracture for its particular payzone in-situ stresses. In conventional fracturing stimulation, only 1 or 2 fractures are feasible. Then few producing layers were employed only in production. Aiming at multiple horizontal fractures should be located exactly in hole, based on its affecting factors intensive analyzing in fracturing and field technological stimulation mechanism research, a study and application of hydraulic jet fracturing (HJF) has been introduced. A 2 stage fracturing of 2.5m space has been finished. It’s a breakthrough or milestone for conventional operation. The successful pilot test has proved that fracture can be located exactly by HJF and then well productivity is enhanced obviously also. According to the operation practice, some feasible operation measures improvement has been discussed in detail. HJF should be the predominant technology for the field.
Study on Delamination Propagation Behavior and Measurement Method for One Kind of New Fiber Metal Laminates
Authors: Huang Xiao , Liu Jian Zhong
Published: June 2012

The delamination at the interface between the aluminium and prepreg layers has greater influence on the fatigue crack growth in fiber metal laminates. To study delamination propagation property of one kind of new fiber metal laminates, by using 2/1 lay-up specimen, this article accomplished delamination propagation test under various stress levels at R=0.1 by optical method and compliance method respectively. The delamination propagation property of this laminate is obtained by analyzing and calculating. A modified compliance equation is created to calculate the delamination size of this laminate more accurately by adding a non-dimensional factor.
Investigation on Wall Thinning and Creep Damage in Boiler Tube due to Scale Formation
Authors: Begum Shahida , Karim A.N. Mustafizul , Shafii M.A
Published: June 2012

Boiler is a closed vessel in which the water is heated up to convert it from the liquid phase to superheat steam at specified pressure by addition of heat. The tubes are operated continuously at high temperature due to the formation of scale which has lower conductivity than that of steel. The scale can be formed for various reasons of which tube geometries, flue gas and steam temperature are prominent. The remaining wall thickness decreases due to the formation of scale which eventually causes failure of the boiler tubes. In this investigation an iterative technique was used to determine the temperature distribution across the tube with the increase of operating time. The operating time was considered up to 160,000 hours. The remaining life of the steam generator tube was found by finding hoop stress and Larson Miller Parameter from the Larson Miller Parameter curve for SA213-T22 material. The remaining life of the steam generator tube was used to find cumulative creep damage. By utilizing finite element modelling software, ANSYS 9/ ANSYS 11 the temperature distribution across the steam generator tube was evaluated. The temperature distribution along with Larson Miller Parameter predicted the oxide scale thickness. It was also observed that different input parameters have pronounced affect on the formation of oxide scale inside the steam generator tube. By increasing the heat transfer rate across the wall, the oxide scale thickness was increased more rapidly than normal condition. It was also observed that due to formation of scale the thermal conductivity in the boiler tubes was affected and the remaining life of boiler tubes was decreased and accelerated creep damage.
Orthogonal Test Research on Compressive Strength Size Effect of ECC
Authors: Deng Ming Ke , Chang Yun Tao , Liang Xing Wen
Published: June 2012

Engineered fiber reinforced cementitious composite (ECC) can significantly improve the seismic performance and durability of concrete structures, which has pseudo strain hardening and multiple cracking performances. Through 32 groups of 192 specimens for compressive strength of ECC, the orthogonal test study on the cube compression failure process, and further research on water binder ratio, fiber content by volume, fly ash content and sand binder ratio of 4 kinds of factors on the size effect of ECC cube compressive strength. The test result shows that: PVA fiber content increases, ECC compressive toughness is improved obviously; water binder ratio and fiber content are the main factors which affect the ECC compressive strength and size effect. When water binder ratio decrease, the compressive strength of ECC materials improve and size effect coefficient increase. Fiber content increase, the compressive strength of test block increase and the size effect coefficient increase. Through the bending tests, we know that: the fiber content by volume increases, the ECC flexural strength of the composite increases gradually.
Mechanical Property Test Study on Composite Board Box
Authors: Xing Huai Nian , Zhang Xiao Peng , Liu Zeng Li , Jin Li Qiang
Published: June 2012

New-style ketchup packaging composite board box is an important technical innovation in ketchup packaging and has broad market prospect because of its economic and recyclable. Some tests including material property test and assembly property test have been done on the new-style composite board box. Different thickness boards such as 20mm, 25mm and 28mm have been tested in the paper. The results show that new-style composite board box can meet the requirements of ketchup packing.
Dynamic Load Effecting on Asphalt Pavement Life by Multi-Intelligence Agents
Authors: Zhang Jun Cai , Zhang Han
Published: June 2012

Calculation model of the varying stress responsing to dynamic road in two degree freedoms is deduced from the moving load effecting on stress change in asphalt pavement structure. There are some constraint conditions and objective factors in varying stress response. Aiming at the impact of qualitative factors which are difficult to quantify, according to specialist experience, system of multi-Agent was established by amending the Agent of knowledge containers and social relationships. Multi-intelligence Agents had an ability of self-adjustment by accommodating itself to environment changes. Then the dynamic task can be solved by intelligent Agent. It reflects objectively the pressure state of the pavement and definitely specific cause for early danage in pavement. This work can provide theoretical guidance for further study the relations between vehicle and pavement.
Bridge Piers and Abutments Surface Degradation Reduction Posibility
Authors: Šnirch Zdeněk
Published: June 2012

Paper deal with influence of on service life and degradation processes at construction of bridge piers and abutments before and after repair actions. Monitored dependencies are then reflect on degradation curves each for a singles construction characteristics (compression strength of concrete, degradation of surface, volume of carbonatation etc.) Pursuant to long-term monitoring of records from bridge piers surface diagnostic we have to be able to unite the records and use them for silicate coatings degradation dependence on bridge piers and abutments and laboratory simulated degradation.
Damage Detection of Wood Beams Using the Modal Flexibility Curvatures
Authors: Hu Chuan Shuang , Wen Wei , Yun Hong
Published: June 2012

Local damages such as knots, decay, and cracks can be translated into a reduction of service life due to mechanical and environmental loadings. In wood construction, it is very important to evaluate the weakest location and detect damage at the earliest possible stage to avoid the future catastrophic failure. In this study, modal testing was conducted on wood beams to generate the first two mode shapes. A novel statistical algorithm was proposed to extract the damage indicator by computing the modal flexibility curvature before and after damage in timbers. Different damage severities, damage locations, and double damages were simulated by removing mass from intact beams to verify the algorithm. The results have shown that the proposed statistical algorithm is effective and suitable to the designed damage scenarios. The proposed algorithm can qualitatively identify the damage existence and its location although there is no linear correlation between damage indicators and damage severities. The peak values of the damage indicators increase when the losses of the second axial moment of area increases. It is also reliable to detect multiple damages.
Simulation of Laser-Induced Cavitation with Lattice Boltzmann Method
Authors: Deng Yu , Guo Zhong Ning , Huang Zhi Gang
Published: June 2012

In this paper, the Lattice Boltzmann Method is applied to set up the numerical model of cavitations. In order to simplify the model without losing the accuracy of simulation, the movement of the bubble wall is considered as the boundary condition for the gas and as initial condition for the fluid so the two phases (gas-fluid) physical phenomenon is divided into two simple models which are connected by the bubble wall. In the simulation, through the analysis of the velocity and the pressure distribution, it is found out that the symmetric bubble is characteristic with pulsation and high speed shock that are limited in a small field with radius of 7mm during the bubble growth. And it noted that the bubble is circularly collapsed for the symmetric velocity distribution.
Study on Interface Structure and In Situ Formation Mechanism in Laser Surface Ceramic Process
Authors: Li Wei
Published: June 2012

Laser ceramic modification technology is an effective way to improve the surface performance of titanium alloy. This paper summarized the in situ formation mechanism of ceramic phases and the interface structure between ceramic phases and the matrix during the laser ceramic process on the surface of titanium alloy. The future research area was also indicated that theoretical study on composite ceramic coating preparation should be strengthened by combining the laser alloying and in situ formation technology on the surface of titanium alloy.
Three Dimensional Simulation and Repair of Skull Maxilla and Dentition Based on CT Scanning and Laser Sintering Technologies
Authors: Yan Gong Xing , Wang Xiao Rong
Published: June 2012

Obtain a prosthesis and carry out maxillofacial repair by rapid prototyping technology on the basis of three dimensional finite element model of maxilla skull and dentition which is obtained through preliminary restoration done on a skull exemplar as modeling material and through spiral CT scanning and three dimensional imaging technologies. Thus, a vivid restored three dimensional biomechanical model and prosthesis of maxilla skull and dentition is obtained, based on which, the form and functions can be restored well after repair. Individual defect model and prosthesis model can be built according to different plans designed for different patients. By which, a complete idea for maxilla and dentition repair can be achieved with pleasing in appearance on patients, low cost and less post-operative complications.
The Effect of Thiourea Additive to Elimination of the Iron Dissolved in Flux Solution of Hot Dip Galvanizing Process
Authors: Moon Kyung Man , Oh Min Seok , Won Jong Pil , Lee Myung Hoon , Kim Yun Hae
Published: June 2012

Hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other fields etc.. Recently, the cost of zinc is getting higher and higher, thus, a proper manufacturing process should be developed possibly to reduce the cost of production. one of hot dip galvanizing process, that is, flux solution immersion process is very important to control more effective coating. However, flux solution is deteriorated with increasing its using time because dissolved iron from structural steel due to continuous flux treatment was increasingly increased, which is resulted in coating badness and increment of dross. In this study, the effect of additives to elimination of iron dissolved in flux solution was investigated with four types of inner solution, that is, solution of inner barrel was filled with seawater, NaOH, NH4Cl, including parameters of amounts of thiourea(0.2,0.4 ,0.6 and 0.8g) and electrolysis experiment was carried out with applied current density at 20mA/cm2. The best effect for elimination of iron from flux solution is considered that inner barrel with separator should be filled with solution different from original flux solution which contained in iron ion, that is, its inner solution should be composed with seawater added with additives such as thiourea(0.4g), NaOH(0.2 g) and NH4Cl(10g). In particular, we can see that the optimum amount of thiourea to extract effectively iron from flux solution is 0.4g.
The Microstructure and Mechanical Properties of the Laser Microwelding Joint for SUS 321 Sheet
Authors: Liu Ge Ping , Chen Yu Hua , Wang Shan Lin , Ge Jun Wei
Published: June 2012

The butt-joint of 0.3 mm SUS 321 plate was welded successfully by micro-pulse laser and the processing parameters were optimized through orthogonal experimental design. The effect of the processing parameters on the microstructure and mechanical properties of the joint with OM, electronic precision stretching machine and other analysis and detection methods. The results indicate that the butt-joint will possesses highest tensile strength of 550 MPa when the optimized processing parameters are the percentage of pulse power of 18, pulse width of 4 ms, pulse frequency of 2 Hz, and the strength of the joint is 98% to the strength of basic metal. The microstructures of joint with high tensile strength are composed of small equiaxial grains in the weld center zone and columnar grains in fusion zone. The microhardness of the joint is higher than that of basic metal.
Effect of Laser Repetition Rate on Silver Nanoparticles Colloid
Authors: Xu Bing , Song Ren Guo , Wang Chao , He Wang Zhao
Published: June 2012

The silver nanoparticles colloid was prepared by pulsed laser ablation in distilled water under various laser repetition rates. The particles size, morphologies and absorption spectroscopy of the obtained nanoparticles colloids were characterized by ultraviolet to visible (UV-Vis) spectrometer and transmission electron microscopy (TEM). The average diameter and its distribution were analyzed by Image-ProPlus software. The results showed that the average diameter of the silver nanoparticles prepared at the laser repetition rate of 10 HZ was the smallest (D=29.75 nm), also, the distribution of particle size decreases with increasing the laser repetition rate.
Numerical Simulation of Residual Stress Field in Laser Transformation Hardening for GCr15 Steel Components and Experimental Study
Authors: Lei Sheng , Yan Yan , Li Heng , Niu Liu , Gui Zhong Xiang , Wu Yue Bo
Published: June 2012

The laser quenching of GCr15 steel by wide band scanning technology was researched. Hardness and depths of laser transformation hardening zones of samples were also measured experimentally. Temperature field and residual stress field in the laser hardening process were numerically simulated by ANSYS software. The calculated results are in good agreement with the experimental results. The distribution of residual stress is closely related to the temperature distribution made by laser heating process. Then the distribution of residual stresses of the laser surface hardened layers was analyzed by using the X-ray diffraction (XRD). Compressive stresses were detected on the surface of the harden layer after the laser transformation hardening process, and the residual stress value of the surface of samples increases with the increasing of laser power. But the residual stress value of surface melting zones of samples is small.
Study on Cellular Structures as the Core Architectures of Parts Based on Selective Laser Melting
Authors: Xiao Dong Ming , Yang Yong Qiang , Su Xu Bin , Zhang Man Hui , Wang Di
Published: June 2012

Cellular structures exhibit favorable properties for multifunctional applications, such as light weight, high load-bearing combined with high heat exchange capability. This paper is to seek optimal cellular structures as the core architectures of parts manufactured by selective laser melting (SLM) technology, which provides required mechanical properties. Design features for characterizing optimal structural performance are discussed. Some preliminary design rules are developed to improve the manufacturability and the quality of cellular structures, the orientation of strut is designed as ±45° or 90°. Compression tests are also carried out to seek cellular structures of synthetically optimal mechanical properties. Comparing the effects of the unit cell architecture and the relative density on mechanical properties, it reveals that unit cell architecture is dominant rather than the relative density, and the truss lattice with [90°,±45°] structure is the overall best performing among the selected cellular structures.
The Image Generating Algorithms of Micro-Pits with Direction-Uniformity Distribution of YAG Laser Texturing Roll Based on Square Partial Scrambling
Authors: Wang Hong Cai , Wang Yang
Published: June 2012

Two image generating algorithms based on square partial scrambling are raised to implement micro-pits with approximate uniformity distribution of YAG laser texturing roll. Micro-pits can be uniformly distributed to ensure the area-uniformity of the micro-pits distribution. Micro-pits can be partial scrambled and optimized according to the evaluation standard to ensure the direction-uniformity of the micro-pits distribution.Partial scrambling image generating algorithms based on square-aligned-array arrangement and square-staggered-array arrangement are both effective image generating algorithms of uniformity distribution. The latter is more effective.
Erosion Wear Resistance of CWS Laminated Ceramic Nozzles
Authors: Deng Jian Xin , Chen Yang Yang , Xing You Qiang
Published: June 2012

In coal-water-slurry (CWS) boilers, the nozzle is eroded continuously by the abrasive action of the CWS, and there are high temperature and temperature gradient inside nozzle, which may cause large tensile stress and lead to an increased erosion wear of the nozzle. In this paper, Al2O3/(W,Ti)C+Al2O3/TiC laminated ceramics were developed to be used as nozzles in CWS boilers. The purpose is to reduce the tensile stresses at the nozzle during the CWS burning process. The value of the residual stresses, which arise from a mismatch between the coefficients of thermal expansion of the constituent phases and neighbouring layers, was calculated by means of the finite element method. The erosion wear behavior of the laminated nozzles was investigated and compared with an unstressed reference nozzle. Results showed that the laminated ceramic nozzles exhibited an apparent increase in erosion wear resistance over the unstressed reference one. It is suggested that laminated structures in ceramic nozzles is an effective way to improve their erosion wear resistance in industrial CWS boilers.
Sliding Wear of Cu-Ag Alloy in Cu Cladding Al Contact Wire
Authors: Zhang Ying Hui , Yang Bin , Qin Jing , Sui Hong Bo
Published: June 2012

The sliding wear behavior of Cu-Ag alloy in Cu cladding Al contact wire against 45# steel or bronze block was tested, then surface morphology was investigated in different load and velocity. The results indicated that the worn surface had plastic deformation and many clear furrows and cutting traces along the sliding direction. There were black oxide of copper on the worn surface. The oxide was both abrasive and lubrication. The mechanisms transformed from abrasive attrition into adhesive wear. Spalling pits and adhesive blocks with bronze friction were significantly bigger than that of steel, and the mechanisms was adhesive wear.
Tribological and Mechanical Properties of Materials for Friction Pairs Used to Space Docking
Authors: Yao Ping Ping , Xiao Ye Long , Zhou Hai Bing , Jin Zong Xiang
Published: June 2012

The microstructures and tribological properties of materials for friction pairs used to space docking were investigated by optical metallographic microscope and a special home-made tribo-tester, respectively. The results demonstrate that friction material appears homogeneous and compact microstructure. Counterpart material presents temper sorbite which keeps martensite morphology and residues a small amount of blocky undissolved ferrite; the porosity of friction material is about 3.7%. Materials for space docking show favorable rigidity; during running-in, friction torque of friction pairs can be enhanced obviously; under different operation conditions, friction pairs for space docking possesses different friction coefficient.
Experimental Investigation for Finite Line Contact Edge Effect of Elastohydrodynamic Lubrication
Authors: Xue Yu , Hua Tong Shu , Sun Hao Yang
Published: June 2012

To reveal the principle of the close effect about the EHL finite roller, contraposing the log-convex roller, the finite line contact EHL film shape and thickness were observed through self-made heavy-load optical EHL experimental device. Experiments were carried out under several different pressure and viscosity, and three groups of interference pictures were obtained under three different entrainment velocities. As the load increased, both the length and width of the roller contact area added, and the width of the contact zone in the end was larger than that in the centre, the close effect was more obvious; when the entrainment velocity and lubricant viscosity increased, the film thickness in the central roller became thicker while the increase in the roller end was little, the high film thickness difference enhanced the close effect. The entrainment velocity, load and lubricant viscosity all have great effect on the EHL characteristics of the finite roller.
Effect of Al on Zn-Al Filler Metal Wettability on Pure Copper Surface
Authors: Zhang Man , Lin Yue Bin , Lv Jian Qiang , Jiang Hai Lin
Published: June 2012

Zn-Al filler metal wettability tests were performed. With the match of CsF-AlF3 flux, Zn-Al filler metal wettability is poor on pure copper surface. The Cu-Al-Zn intermetallic compound interface layer exits between Zn-Al filler metal and Cu base metal. When Al content is low in Zn-Al filler metal, the filler metal wettability is poor and the filler metal melting point is low. In the wettability test course, the time is long in which Cu base metal interacts with liquid Zn-Al filler metal. And the Cu-Al-Zn intermetallic compound interface layer grows thick between filler metal and base metal. With the increase of Al content in Zn-Al filler metal, the interaction strengthens between Zn-Al filler metal and Cu base metal. In the wettability test course, the time beocome short in which Cu base metal interacts with liquid Zn-Al filler metal. The Cu-Al-Zn intermetallic compound interface layer gets thin between filler metal and base metal. Meanwhile, Zn-Al filler metal wettability improves on pure copper surface. But the improvement is not remarkable. Its wettablility is still poor on pure copper surface.
Design of Main Pump Motor’s Water Lubricated Bearing and Research on its Lubrication Performances
Authors: Wang Xin Rong , Li Xiao Hai , Cui Ya Chao , Yang Li Hua
Published: June 2012

Water-lubricated thrust bearing is a key component of certain main pump motor. In this paper, the right structure of water-lubricated thrust graphite bearings is designed based on low viscosity hydrodynamic lubrication theory by combining the bearings running working condition, and the frictional accessory material is also determined by theoretical analysis and test. The factors influencing lubrication performances of water-lubricated thrust bearings are analyzed; the methods improving lubrication performances are put forward to guarantee that water-lubricated thrust graphite bearings have the good lubrication performances, good carrying capacity and longer work life.
Effect of Isothermal Heat Treatment on Abrasive Wear Resistance of HVOF WC-10Co-4Cr Coating
Authors: Ding Kun Ying , Cheng Tao Tao , Lu Peng Cheng
Published: June 2012

WC-10Co-4Cr cermet coatings were deposited on Inconel 718 alloy using the HVOF technique, then were heat treated by isothermal treatment (500°C, 3hours). The influences of isothermal heat treatment on micro-hardness, fracture toughness and abrasive wear resistance of WC coating were studied in this paper. The results show that the micro-hardness and fracture toughness of WC coating decrease after isothermal heat treatment, then the metallic blinder breaks up and the tungsten carbide particles pull out during abrasive wear test. Finally, it was concluded that the abrasive wear resistance of WC-10Co-4Cr coating decreased after isothermal heat treatment (500°C, 3hours).
Finite Element Analysis of Technology of Spontaneous Heating to Deice and Melt Snow
Authors: Li Hong Lei , Cen Guo Ping , Gu Qiang Kang
Published: June 2012

The technology of spontaneous heating is a new method of deicing and melting snow.It puts electrical conductor into asphalt concrete.After electrical conductor sending out heat,temperature of pavement will be increased.Untill temperature is higher than freezing point,ice and snow will be melted.According to theory of heating,a model of finite element is designed.Based on ANSYS,temperature field of pavement layer and temperature distribution of pavement surface,ascending rule of temperature,warm-up time,affection of deicing and snow-melting are researched.Finally,curved line and analyzed result of deicing and melting snow are received.The result can demonstrate the feasibility of technology of spontaneous heating to deice and melt snow on airport pavement.
Investigation of Parameter Effect to Performance of Battery's Cooling System
Authors: Li Zhen Zhe , Pan Xiao Ming , Ren Ming , Li Mei Qin , Shen Gui Ying
Published: June 2012

With the heightened concern for energy consumption and environment conservation, the interest on fuel cell HEV (hybrid electric vehicle) has been greatly increased. In this study, a numerical model for the cooling system of batteries was constructed. Using the constructed analysis model, the material of the cartridge and the cartridge width were checked for improving the performance of the cooling system of batteries. The performance was changed by using different cartridge material, and the cartridge width also has an effect to the performance of the cooling system of batteries as shown in the analysis results. The constructed model and method can be used to investigate the performance of the cooling system of batteries.
Numerical Simulation of Cooling System of Battery Using Parameter Study
Authors: Jiang Rui , Li Zhen Zhe , Shen Gui Ying , Ren Ming , Li Mei Qin
Published: June 2012

A hybrid power composed of fuel cell and MH-Ni battery has become a good strategy for HEV, but the battery cooling system can not be easily optimized because of many important parameters. In this study, the parameter studies have been carried out for checking the effects of the parameters. The candidated parameters in this study were the diameter of the outlets and the distance between the outlets. The analysis results show that the diameter and the distance have the effects expressed by a 2nd order function form. The analysis model and the results in this study make a basis for optimizing the battery cooling system.
Effect of Heat Input on Impact Toughness of Coarse-Grained Heat-Affected Zone of a Nb-Ti Microalloyed Pipeline Steel
Authors: Gao Zhou , Wei Ran , Wu Kai Ming
Published: June 2012

The effect of varying heat inputs (20, 100, 200 kJ/cm) on the microstructures and toughness of the simulated coarse-grained heat-affected zone of a Nb-Ti microalloyed pipeline steel were investigated utilizing optical and electron microscope. Results showed that the impact toughness of the coarse-grained heat-affected zone maintained a higher level at the heat input of 20 and 100 kJ/cm, whereas it dropped to a much lower level at the heat input of 200 kJ/cm. The good toughness was attributed to the grain refinement and the homogenous distribution of fine and elongated martensite/austenite constituents. The deterioration of toughness for high heat input simulated welding was mainly caused by the coarse bainitic microstructure and massive martensite/austenite constituents.
Parameter Study on Cooling System of Battery for HEV
Authors: Li Zhen Zhe , Shen Yun De , Shen Gui Ying , Li Mei Qin , Ren Ming
Published: June 2012

A hybrid power composed of the fuel cell and MH-Ni battery has become a good strategy for HEV, but the performance of the battery cooling systems can not be easily adjusted. In this study, heat flux of the batteries and mass flow rate of cooling air have been investigated to improve the performance of a battery cooling system. As shown in the results, the error of root mean square has been decreased under the condition of decreasing heat flux of the batteries, and the performance of the battery cooling system has been improved with increasing the mass flow rate of cooling air. The analysis model developed in this study can be widly used to find out an optimal battery cooling system in the future work.
Effect of Heat Treatment on Thermal Conductivity of Aluminum Die Casting Alloys
Authors: Cingi Celal , Rauta Veijo , Suikkanen Esa , Orkas Juhani
Published: June 2012

Thermal conductivity is an important property when high heat dissipation is a requirement during the use of the cast component. This study was carried out to study the effect of heat treatment on thermal conductivity of three common aluminum die casting alloys. Measurement of thermal conductivity was done by the Hot Disk method. A substantial increase in thermal conductivity was measured as a result of heat treatment. Microstructural changes due to heat treatment was examined by optical and scanning electron microscopy.
Numerical Simulation Study on Thermal-Hydraulic Performances of Vehicular Radiator Heat Transfer Units
Authors: Zheng Yang , Xiao Bao Lan , Wu Wei Ming , Yu Xiao Li , Lu Guo Dong
Published: June 2012

A radiator is one of the most important components in vehicular cooling system whose excellent fluid flow and heat transfer characteristics guarantees the engine operations. The calculation workload for performance simulation of a whole radiator is too huge due to its size. Experimental study is the conventional method to study radiator performance. This paper put forward a numerical simulation method and radiator heat transfer units were taken as study objects. Orthogonal experiment method was adopted to arrange multi-factor and multi-level calculation schemes. 23 samples with different fin parameters were simulated to investigate their thermal-hydraulic performances. Compared with experimental testing, this method greatly reduced sample manufacturing cost and testing cost, and offered data support for the effect factor study of radiator heat transfer units.
Research on Friction and Wear Properties of Plasma Spraying Ni-Base Alloy Coatings on Aluminum Alloy Surfaces
Authors: He Long , Tan Ye Fa , Cai Bin , Tan Hua , Gao Li , Zhang Zhong Wei
Published: June 2012

In order to improve the wear resistance and extend service life of aluminum alloy parts, the Ni-base alloy anti-wear coatings were prepared on the surfaces of 7A05 aluminum alloy by plasma spraying technology. The microstructure and interface of the coatings were analyzed, and the friction and wear properties of Ni-base alloy coatings and aluminum alloy substrates were investigated under dry friction condition at room temperature. The research results show that the main phases of Ni-base alloy coating are γ-Ni, CrB and Cr23C6. The thicknesses of diffusion layers existing between intermediate layer and coating, intermediate layer and substrate are respectively 15μm and 20μm. The bonding types of the coating and the substrate are mechanical combination accompanied with partially metallurgical combination. When wore against GCr15 steel balls, the average friction coefficient of the Ni-base alloy coatings is 11.6% lower than that of the aluminum alloy substrates, and the average wear loss of the former is 9.3mg, which is only 1/3 of that of the latter. With the increase of loads, the wear mechanisms of the Ni-base alloy coatings change from slightly micro-cutting wear and fatigue wear to abrasive wear and micro-fracture wear, while those of the aluminum alloy substrates are mainly adhesive wear and abrasive wear as well as slight oxidation wear.
Thermal Analysis of Coal-Bearing Strata Kaolinite/potassium Acetate Intercalation Complex
Authors: Yao Xiang , Zhang Shuai , Sun Bo
Published: June 2012

The thermal decomposition of coal-bearing strata kaolinite-potassium acetate(CK/KAc) intercalation complex has been studied using X-ray diffraction (XRD), thermogravimetry and differential thermogravimetric (TG-DTG) and infrared emission spectroscopy (IES). The XRD results show that the KAc has been successfully intercalated into coal-bearing strata kaolinite with an obvious basal distance increase of the first basal peak. The TG results show that the thermal decomposition of the intercalation complex occurs in four main steps (a) the loss of adsorbed water (b) the loss of coordination water (c) the loss of potassium acetate and (d) water through dehydroxylation. The IES of CK/KAc give the evidence on the changes of structure. These make all explanation have the sufficient evidence.
Thermodynamic Evaluation for the Synthesis of T2 Phase from Elemental Powders via In Situ Reactively Hot-Pressing
Authors: Zhang Lai Qi , Huang Lei , Hou Yong Ming , Lin Jun Pin
Published: June 2012

T2 phase(Mo5SiB2) is a key component of the two Mo-Si-B tri-phase alloys under hot research. However, there is little research on T2 phase, especially its mechanic characteristics, due to the difficulty of fabrication of pure T2. In this present work, the thermodynamics of an advanced technology to fabricate pure T2 phase i.e. IRHP (In-situ Reactively Hot-Pressing) using elemental powders was analyzed. Formation free enthalpies at different temperatures for the compounds in Mo-Si-B system were calculated. Adiabatic temperatures and molten fractions of T2 phase at different initial temperatures for the reaction of synthesizing T2 phase were evaluated. The results show that it is feasible to in-situ synthesize T2 phase from elemental powders. T2 phase can not be synthesized using SHS(Self-propagating High-temperature Synthesis) mode of combustion. On the contrary, the explosion mode of combustion (IRHP) is receivable. Adiabatic temperature and molten fraction of T2 phase are relevant to initial temperature.
The Influence of Oil on the Evaporation Heat Transfer of R-600a Refrigerant inside a Micro-Fin Tube within Inserts
Authors: Wen Mao Yu , Jang Kang Jang
Published: June 2012

Evaporation of refrigerant-oil mixture was studied in a smooth and micro-fin tube without / with four different inserts (twined coil, wire coil, twisted tape, and helical-coil). The refrigerant was R-600a and the oil was the EMKARATE RL 32H with a viscosity 150 SUS. The test was conducted at a saturation temperature of 15 , vapor qualities from 0.1 to 0.49, inlet oil concentration from 0 to 5 mass% oil, mass flux of 200 – 500 and heat flux of 10.24 . The enhancement factor (EFs) is larger for the lower oil concentration (at l %), while the ratios for the higher oi1 concentration (at 5%) are generally smaller than l and decreased rapidly as the oil concentration increased. In addition, new correlations to estimate the evaporation heat transfer coefficients for the R-600a mixed with the lubricating oil in micro-fin tube containing different inserts have been developed.