Table of Content

    30 October 2012, Volume 17 Issue 5 Previous Issue    Next Issue

    For Selected: Toggle Thumbnails
    Super-Capacitive Performances of Nickel Foam Supported CeO2 Nanoparticles
    HU Ye-min* (胡业旻), SHI Tao-tao (史涛涛), NI Jian-sen (倪建森), JIN Hong-ming (金红明), ZHU Ming-yuan (朱明原), LI Ying (李瑛), BAI Qin (白琴)
    2012, 17 (5):  513-516.  doi: 10.1007/s12204-012-1316-7
    Abstract ( 2359 )  
    This paper designs and fabricates CeO2 nanoparticles on a large scale by hydrolysis and oxidation of cerium carbide. The electrochemical supercapacitor behavior of CeO2 nanoparticles was investigated. The nickel foam (NF) supported CeO2 nanoparticles show a high areal capacitance of 119 mF/cm2, demonstrating a strong synergistic effect between NF and CeO2 nanoparticles. The high capacitance of the CeO2/NF nanoparticles is possibly due to an improved conductivity by NF and a better utilization of CeO2 nanoparticles.
    References | Related Articles | Metrics
    Synthesis of Sub-micrometer Lithium Iron Phosphate Particles Using Supercritical Hydrothermal Method for Lithium Ion Batteries
    LIU Xue-wu1,2*(刘学武), WEI Hao1 (魏浩), DENG Yuan-fu2 (邓远富), TANG Jie1 (汤洁), SHI Zhi-cong2 (施志聪), CHEN Guo-hua2,3 (陈国华)
    2012, 17 (5):  517-522.  doi: 10.1007/s12204-012-1317-6
    Abstract ( 1790 )  
    In this study, sub-micrometer LiFePO4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries. Experimental results show that templates and calcination time have significant impacts on the purity, particle size and morphology of LiFePO4 particles. The as-prepared LiFePO4 particles using polyvinyl pyrrolidone (PVP) template with additional one hour calcination at 700℃ exhibit characteristics of good crystallinity, uniform size distribution, high capacity and cycling performance. The specific discharge capacities of 141.2 and 114.0mA· h/g were obtained at the charge/discharge rates of 0.1 and 1.0 C, respectively. It retained 96.0% of an initial capacity after 100 cycles at 1.0 C rate. The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.
    References | Related Articles | Metrics
    Effect of Oxygen Content on Structural and Optical Properties of Single Cu2O Film by Reactive Magnetron Sputtering Method
    LI Bin-bin1,2*(李斌斌), ZHU Jian-xun2 (朱建勋), CHEN Zhao-feng1 (陈照峰), SHEN Hong-lie1 (沈鸿烈), LUO Jian1 (罗建)
    2012, 17 (5):  523-526.  doi: 10.1007/s12204-012-1318-5
    Abstract ( 2273 )  
    Cuprous oxide (Cu2O) thin films have been deposited on glass substrate by reactive magnetron sputtering method using Cu target and argon oxygen gas atmosphere. Effect of oxygen flow rate on structural and optical properties of thin films has been discussed. The results of X-ray diffraction, ultraviolet-visible spectrophotometry and atomic force micrograph indicated that the condition window for single Cu2O phase was about 3.8 to 4.4 cm3/min, and the optimum oxygen flow rate was 4.2 cm3/min. The optical band gap Eg of Cu2O film was determined by using the data of transmittance versus wavelength, and slightly decreased from 2.46 to 2.40 eV with the increase of oxygen flow rate from 3.8 to 4.4 cm3/min. The Cu2O film formed at the oxygen flow rate of 4.2 cm3/min had an optical band gap of 2.43 eV.
    References | Related Articles | Metrics
    Ultrasonic Nondestructive Testing and Evaluating System for the Brazing Quality of a Guide Ring
    GAO Shuang-sheng1 (高双胜), CHI Da-zhao2* (迟大钊), GANG Tie2 (刚铁)
    2012, 17 (5):  527-530.  doi: 10.1007/s12204-012-1319-4
    Abstract ( 1371 )  
    The important status of guide ring in large power plants and its manufacturing methods were introduced. The advantages of manufacturing methods including welding and electrolysis were discussed. In order to ensure the brazing quality of the guide ring, ultrasonic nondestructive testing (UNDT) method was used in this study. According to the features of the defects that may show up during brazing, the feasibility and reliability of UNDT were proved in theory. Based on the theory, an ultrasonic C-scan imaging test method was developed using a water immersion focusing probe. According to the features of the inspected images, the defects were segmented using a morphology image processing based method. The defects can be localized and sized by employing the algorithm of area reconstruction. At last, the combination ratio of brazing interface can be calculated and the brazing quality of the guide ring can be evaluated.
    References | Related Articles | Metrics
    Investigation on Blanking of Thick Sheet Metal Using the Ductile Fracture Initiation and Propagation Criterion
    YU Songa* (虞松), ZHAO Junb (赵军)
    2012, 17 (5):  531-536.  doi: 10.1007/s12204-012-1320-y
    Abstract ( 1679 )  
    In metal forming processes such as sheet blanking, severe plastic deformation localizes in a narrow shear band near blanking clearance, and ductile fracture occurs at the final stage. Because the combinations of large nonlinear strain localization, displacement discontinuity and ductile fracture brought obstacles to numerical simulation, a ductile fracture initiation criterion model and an elasto-plastic finite element method (FEM) were presented to simulate localized severe plastic deformation. Initiation and propagation of cracks were treated by deletion-and-replacement approach. The distributions and developing trends of effective strain and damage were predicted, the influence of blanking clearance on fracture was discussed, and an experiment was performed to explore the forming mechanism.
    References | Related Articles | Metrics
    Animal Experiment of Viscose Carbon Fiber Based C/C Composites Applied in Bone Fracture Intramedullary Fixation
    CAO Ning1* (曹宁), WANG Wen-bo2 (王文波), DONG Jian-wen2 (董建文)
    2012, 17 (5):  537-540.  doi: 10.1007/s12204-012-1321-x
    Abstract ( 1378 )  
    The animal experiment of viscose carbon fiber based C/C composites applied in bone defection intramedullary fixation was carried out in New Zealand white rabbits. The histological observation on the 100th day after surgical operation indicated that the experimental animals recovered well and the bone defect area was reconstructed by new bone trabecula. Immunohistochemical observation of leukocyte common antigen and macrophage suggested that intramedullary fixation materials did not induct any chronic toxicity reactions such as inflammatory reactions, macrophage reactions and formation of granulation tissue. The tissue compatibility of this material was excellent. Meanwhile, the impurity element species and the biological toxic element content of viscose fiber based C/C composites were determined by atomic fluorescence analyzer and inductively coupled plasma atomic emission spectrometry. The results reveal that there are few biological toxic elements in the viscose fiber based C/C composites and it can satisfy the constituent demands of surgical implants.
    References | Related Articles | Metrics
    Preparation and Characterization of a New Kind of Nano-rod Shaped Polycarboxylate Slump-Retaining Admixture Using for Concrete
    DUAN Guo-rong1,2* (段国荣), HUANG Guo-hong1,2 (黄国泓), LI Ai-mei2 (李爱梅), ZHU Ye-ran (朱烨然), GONG Ying1,2 (龚英)
    2012, 17 (5):  541-544.  doi: 10.1007/s12204-012-1322-9
    Abstract ( 1440 )  
    A new kind of nano-rod shaped polycarboxylic acid slump-retaining agent was synthesized. Transmission electron microscope (TEM) experiment showed that the nano-rod was bound together as macromolecular aggregates in solution. Application performance studying suggested that this kind nano-sized polymer material had excellently plasticity-retaining performance in cement-based materials and could improve endurance performance of hardened cement-based materials distinctly. The concrete with an initial slump of 2—9 cm could achieve 3 h plasticity-retaining performance with the help of this kind nano-rod. The product had extremely wide application value in the market.
    References | Related Articles | Metrics
    Mechanical Properties of Perfect and Defective Zigzag Single-Walled Carbon Nanotubes Under Axial Compression
    XIN Hao1 (辛浩), HAN Qiang2,3* (韩强)
    2012, 17 (5):  545-551.  doi: 10.1007/s12204-012-1323-8
    Abstract ( 1369 )  
    Axial buckling behavior of perfect and defective zigzag single-walled carbon nanotubes (SWCNTs) is studied by molecular dynamics (MD) simulations. Different effects of three typical categories of defect on the axial buckling properties of SWCNTs are investigated. MD simulation results show that the buckling behavior of defective tubes is quite different from the perfect tube. The critical buckling load of zigzag SWCNTs is significantly reduced with different defect appeared in the tube wall, and the effective elastic modulus are also slightly but distinguishingly influenced by individual defect. It is revealed that an Stone-Thrower-Wales defect could induce greater decrease of the rigidity a single vacancy defect or a double vacancies one. The harmful effects of defects do not depend simply on the size of the defective area, but related strongly to the buckling modes of the defective SWCNTs which specifically differ from each other due to the different defect structures.
    References | Related Articles | Metrics
    Study on Toughening on Crack Prevention of Jointed Rock Masses with Different Pre-Stress Anchor Cables
    WANG Zhong-chang1,2* (王忠昶), ZHAO De-shen2 (赵德深), WU Hui-jun1 (吴会军)
    2012, 17 (5):  552-558.  doi: 10.1007/s12204-012-1324-7
    Abstract ( 1069 )  
    The major reason of the failure of jointed rock-mass is the formation of the plastic zone near the crack tip of I-II mixed crack which leads to the growth, propagation of the branched crack under load condition. In the paper, the failure judgment of mini-plastic zone’s displacement is derived by the Mises yielding rule. The anchor cable is simulated by the different link elements and inflicting pre-strains according to the difference of mechanism of the consolidated segment and free segment. The stress and strain fields near crack tip of twain collinear cracks of different angles and consolidated conditions are simulated by iso-parametric element with eight nodes. The iso-parametric element with eight nodes is degenerated to singular element at crick tip to simulate crack. It is shown that the mini plastic zone’s displacement near the crack tip begins to increase, then decreases with the increase of the angle of the crack. The better consolidated condition is, the smaller the angle of crack tip is when the mini plastic zone’s displacement near the crack tip arrives at the biggest value. The mini plastic zone’s displacement near the crack Tip 2 is bigger than that near the crack Tip 3. The crack is easier to failure with the increase of load.
    References | Related Articles | Metrics
    Interaction of Human Fibroblasts with Electrospun Composites Gelatin/PLLA, Chitosan/PLLA and PLLA Fibrous Scaffolds
    LI Jian-boa,b (李建波), HAN Junb (韩君), REN Jieb,c* (任杰)
    2012, 17 (5):  559-566.  doi: 10.1007/s12204-012-1325-6
    Abstract ( 1233 )  
    Highly porous ultrafine electrospun scaffolds, gelatin/poly(L-lactic acid) (PLLA) and chitosan/PLLA were prepared by blending gelatin and PLLA, chitosan and PLLA respectively. The biocompatibilities of these scaffolds were assessed by attachment, proliferation and viability of cells on them. The results indicated that over 30% WI-38 cells could attach to the gelatin/PLLA and chitosan/PLLA scaffolds at 2 h after seeding, while the attachment of the cells was only 15% on PLLA scaffolds. Both gelatin/PLLA and chitosan/PLLA scaffolds also exhibited a very good ability for proliferation of WI-38 cells. Cell growth on the gelatin/PLLA and chitosan/ PLLA scaffolds showed dramatic improvement, indicating a much better biocompatibility in the blends contributed by gelatin and chitosan. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay also demonstrated gelatin/PLLA showed better ability to enhance the growth and functions of the cells. These assays suggest that the electrospun gelatin/PLLA and chitosan/PLLA scaffolds are promising biomaterials with great biocompatibility for the development of skin tissue engineering.
    References | Related Articles | Metrics
    Research on Modeling and Fuzzy Control of Magneto-Rheological Intelligent Buffer System for Impact Load
    FU Li1* (傅莉), LIN Li-ping1 (林丽平), XU Xin-he2 (徐心和)
    2012, 17 (5):  567-572.  doi: 10.1007/s12204-012-1326-5
    Abstract ( 1214 )  
    So far the magneto-rheological (MR) effect mechanism of MR damper has not been known completely, especially in the impact load, and the problem becomes more complicated and difficult for analyzing. A set of characteristic tests and parameters’ identification are made to the MR damper by the experimental platform. The dynamical model of the damper is constructed based on the Bingham plastic model, and the buffer control strategy of aircraft undercarriage based on MR technology is established. Finally, the fuzzy control algorithm is applied to the process of automatic control for landing buffer of aircraft undercarriage. The simulation results show that the proposed MR damper pulley buffer can effectively recognize the impact energy. The research has a better application in the engineering.
    References | Related Articles | Metrics
    Modeling and Control of the Pulley Buffer System of Arresting Cable for Shipboard Aircraft Based on Magneto-Rheological Fluid
    FU Li1 (傅莉), WEI Ying2*(魏颖), ZHOU Yan-kai1 (周彦凯), CHENG Tao1 (程涛)
    2012, 17 (5):  573-578.  doi: 10.1007/s12204-012-1327-4
    Abstract ( 1330 )  
    Taking the MK7-3 of USA hydraulic buffer arresting device as the research subject, the dynamical model for the shipboard aircraft arresting system is established, and the magneto-rheological (MR) damper is applied to pulley shock absorbers for shipboard aircraft block system. Due to the effect of the MR damper has not been known completely and so far MR damper model has not been defined, we use a set of characteristic test of the MR damper, through the process of parameters identification, to establish the dynamical model for the MR damper based on the Bingham plastic model. Then, the fuzzy control rules are designed, the buffer control for the pulley buffer of shipboard aircrafts is completed in touchdown moment based on MR technology. Compared with blocking device of hydraulic pulley buffer in the same condition, the simulations results show that the proposed MR pulley buffer can effectively recognize the impact energy for shipboard block system and reduce the pull peak of arresting cable. It improves significantly safety during landing of the air vehicles and lowers the risk of accidents.
    References | Related Articles | Metrics
    Modified Nafion Polymer Electrolyte Membranes by γ-Ray Irradiation Used in Direct Methanol Fuel Cells
    SUO Chun-guang1,2* (索春光), ZHANG Wen-bin3 (张文斌), WANG Hua4 (王华), YANG Feng-jie5 (杨凤杰)
    2012, 17 (5):  579-585.  doi: 10.1007/s12204-012-1328-3
    Abstract ( 1342 )  
    Modification of the commercial polymer electrolyte membrane (PEM) Nafion 117 by γ-ray irradiation to produce an improved proton exchange membrane for direct methanol fuel cells (DMFCs) was described. The Nafion 117 membrane was exposed under γ-ray irradiation circumstance with the irradiation doses from 103 to 105 Gy. Subsequently the properties of the membrane itself, in terms of swelling ratio, water uptake rate, proton conductivity and methanol permeability, together with the performance of its membrane electrode assembly (MEA) in DMFC were analyzed and contrasted with the untreated material. When the Nafion 117 membrane was exposed under γ-ray irradiation circumstance, the degradation and crosslinking reactions occurred at the same time. Specific scopes of the γ-ray irradiation dose may cause the membrane crosslinking, thus reduce the membrane swelling ratio and decrease the methanol crossover. By reducing the membrane swelling ratio and methanol permeation, the single DMFC with the modified Nafion 117 membrane produced reasonable power density performance as high as 32W/m2 under 2mol/L methanol solution at room temperature.
    References | Related Articles | Metrics
    Preparation and Characterization of the Covalent-Integrated Poly(lactic acid) and Scrap Leather Fiber Composites
    DUAN Jing-kuan1* (段景宽), FAN Chang-xiu1,2 (范常秀), LI Ya1 (李亚), JIANG Lan1 (蒋岚), SHAO Shuang-xi1 (邵双喜)
    2012, 17 (5):  586-592.  doi: 10.1007/s12204-012-1329-2
    Abstract ( 1114 )  
    Scrap leather fibers (SLFs) modified with active silane containing epoxide groups were incorporated into poly(lactic acid) (PLA) modified by vinyl trimethoxysilane, i.e., the PLA/SLF composites were prepared for bio-composites by solvent compounding technology in this article. The effects of silane coupling agents on the structures of PLA and SLF molecules were examined, and the mechanical properties and thermal stability of PLA/SLF composites were also measured. The results of Fourier-transform infrared spectroscopy (FTIR) had proved that silane had been incorporated successfully to PLA and SLF molecules by means of the solvent technology. Scanning electric microscopy (SEM) was used to investigate both the changes in shapes between the pristine SLFs and the treated SLFs and the microscopic structures of composites. According to SEM results, it was shown that there were some significant differences between the untreated and treated SLFs, and a double continuous phase structure had occurred in PLA/SLF composites due to the excellent dispersion of SLFs in matrix. The addition of the treated SLFs into PLA resulted in a distinct improvement of the impact and tensile strengths. When the mass fraction of the treated SLFs was 15%, the notched impact strength and tensile strength of PLA/SLF bio-composites were improved by 34.4% and 21.2% compared with the pristine PLA, respectively. Additionally, with the increase of the modified SLFs content, the thermal stability of PLA/SLF bi-composites was apparently improved. The macroscopic properties of bio-composites were found to be strongly dependent on their components, concentration, dispersion and resulted morphological structures.
    References | Related Articles | Metrics
    A Method for Determining Surface Free Energy of Bamboo Fiber Materials by Applying Fowkes Theory and Using Computer Aided Machine Vision Based Measurement Technique
    LU Jun1 (陆军), ZHANG Hong-tao2 (张红涛), WEI De-yun3* (魏德云), HU Yu-xia4 (胡玉霞)
    2012, 17 (5):  593-597.  doi: 10.1007/s12204-012-1330-9
    Abstract ( 1237 )  
    The purpose of this study is to develop a standard methodology for measuring the surface free energy (SFE), and its component parts of bamboo fiber materials. The current methods was reviewed to determine the surface tension of natural fibers and the disadvantages of techniques used were discussed. Although numerous techniques have been employed to characterize surface tension of natural fibers, it seems that the credibility of results obtained may often be dubious. In this paper, critical surface tension estimates were obtained from computer aided machine vision based measurement. Data were then analyzed by the least squares method to estimate the components of SFE. SFE was estimated by least squares analysis and also by Schultz’ method. By using the Fowkes method the polar and disperse fractions of the surface free energy of bamboo fiber materials can be obtained. Strictly speaking, this method is based on a combination of the knowledge of Fowkes theory. SFE is desirable when adhesion is required, and it avoids some of the limitations of existing studies which has been proposed. The calculation steps described in this research are only intended to explain the methods. The results show that the method that only determines SFE as a single parameter may be unable to differentiate adequately between bamboo fiber materials, but it is feasible and very efficient. In order to obtain the maximum performance from the computer aided machine vision based measurement instruments, this measurement should be recommended and kept available for reference.
    References | Related Articles | Metrics
    Semirigid Analysis of Extended End Plate Connections Based on Correlation and Sensitivity
    PAN Jian-rong (潘建荣), WANG Zhan* (王湛), ZHENG Lin-qiang (郑霖强),LIN Zi-xing (林梓兴), HE Yi-ming (何一鸣), ZHU Qing-ling (朱庆玲)
    2012, 17 (5):  598-604.  doi: 10.1007/s12204-012-1331-8
    Abstract ( 1081 )  
    Traditionally, semi-rigid analysis of extended end plate connections is assumed to be deterministic parameters. Most of the moment-rotation models of the joint are determined by curve-fitting and statistically regressed with the test data. Parameters of these models have little physical meaning, and the effect of correlations in the parameters is neglected. This paper deals with a semi-rigid joint of extended end plate connections based on correlation and sensitivity analysis. A numerical study was carried out and the finite element analysis was validated compared with the experimental results. The relative moment-rotation model was concluded based on correlations in parameters and probabilistic sentivity analysis. The relationship between height and width of steel beam was partial correlation. The relationship between thickness of steel beam flange and thickness of steel beam web was also partial correlation. Height and width of steel beam, and distance of upper bolts to axle wire of steel beam section were important sensitive parameters for the extended end plate connections.
    References | Related Articles | Metrics
    Research on Magnetomechanical Coupling Effect of Q235 Steel Member Specimens
    XIONG Er-gang1* (熊二刚), WANG She-liang2 (王社良), MIAO Xiao-yu1 (苗晓瑜)
    2012, 17 (5):  605-612.  doi: 10.1007/s12204-012-1332-7
    Abstract ( 1098 )  
    In this study, magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment. Hysteresis loops were obtained in different magnetic fields and stresses. Magnetization curves were also achieved at different stresses. Influence of the applied stresses on the hysteresis loops was investigated. The stress sensitive region and linear stress sensitive region of magnetic induction were determined for the model specimen according to the experimental data. The dependence relation of magnetic induction versus applied stresses was established, and the optimum magnetic field was determined in the stress sensitive range of magnetic induction, which builds a basis for nondestructive testing (NDT) of stress with the total magnetic flux for steel structure. Based on modified Jiles-Atherton’s model of magnetic hysteresis, the hysteresis loop for Q235 steel 4-mm diameter model specimen was numerically simulated, which was well consistent with the experimental results.
    References | Related Articles | Metrics
    Flexural Experimental Study on Continuous Reinforced Concrete Beams Strengthened with Basalt Fiber Reinforced Polymer/Plastic
    OUYANG Li-juna,b* (欧阳利军), LU Zhou-daoc (陆洲导), CHEN Wei-zhenb (陈惟珍)
    2012, 17 (5):  613-618.  doi: 10.1007/s12204-012-1333-6
    Abstract ( 2015 )  
    This paper discusses a new fibrous composite known as continuous basalt fiber reinforced polymer/ plastic (BFRP). Compared with other fiber reinforced polymer/plastic, BFRP has many advantages, such as ductility, high thermal resistance, corrosion resistance and economic cost. To test mechanical properties and failure modes of flexural members strengthened with BFRP, flexural experiment is conducted on four two-span T-section continuous beams strengthened with BFRP and one un-strengthened comparative beam. The experimental result shows that the strengthened beams perform remarkably in terms of yield strength, ultimate strength and ductility. BFRP has good prospects in retrofitting and strengthening of concrete structures which require good ductility and corrosion resistance.
    References | Related Articles | Metrics
    Analysis of Localization of Mohr-Coulomb Strength Law with Damage Effect
    WANG Zhong-chang1,2* (王忠昶), WANG Hai-tao1,2 (王海涛), YANG Qing2 (杨庆)
    2012, 17 (5):  619-628.  doi: 10.1007/s12204-012-1334-5
    Abstract ( 1125 )  
    The damage critical curved surface is derived by considering the related effect of isotropic damage and degradation of cohesion and internal friction angle of Mohr-Coulomb strength law. The characteristics of stress-displacement curve and networks of shear bands with the change of degree of damage, confining pressure and Poisson’s ratio are investigated numerically by monitoring the stress-displacement values in the process of deformation of samples under plane strain and different initial conditions. The dependence of elastic-plastic response of localization is discussed. The non-uniqueness of the solution of equation is given. The orientation angle of shear band is derived by considering the related effect of isotropic damage and degradation of cohesion and internal friction angle. The orientation angle of shear band obtained by numerical simulation is contrasted to the orientation angle by measuring Mohr circle. It is shown that peak strength and residual strength depend on confining pressure. The networks of shear bands begin to appear in phase II of elasticity and develop in soften phase, and the shear band is formed in the phase of residual strength. As the degree of damage increases, axial displacement at the points of bifurcation and shear band decreases. The orientation angle of shear band increases with the increase of the damage degree. The orientation angle of shear band obtained by numerical simulation and measuring Mohr circle is not much difference when the damage degree is equivalent. The Mohr-Coulomb theory may predict the localized instability of sample by considering the degradation of cohesion and internal friction angle.
    References | Related Articles | Metrics
    Effects of Mineral Admixtures and Superplasticizers on Micro Hardness of Aggregate-Paste Interface in Cement Concrete
    WANG Zhen-jun* (王振军), WANG Qiong (王琼), WEI Yong-feng (魏永锋)
    2012, 17 (5):  629-634.  doi: 10.1007/s12204-012-1335-4
    Abstract ( 1335 )  
    This paper presents quantitatively the results of an experimental investigation on influence of mineral admixtures and superplasticizers on Vickers micro hardness (HV) of aggregate-paste interface in cement concrete. The HV was measured by Vickers hardness testing equipment. The results indicate that addition of fly ash decreases HV of the concrete. Although it decreases with the increase of ground granulated blast furnace slag (GGBS) replacement, the HV is higher than that of concrete containing fly ash at all replacements. The flying ash and GGBS composition increases HV in later curing ages, but does not improve it in early curing ages. Aminosulfonic acid based superplasticizer and aliphatic hydroxy sulphonate condensate superplasticizer can enhance HV in early curing ages. The HV of concrete with polycarboxylic acid superplasticizer is higher in later curing ages.
    References | Related Articles | Metrics
    Forming Path Optimization for Press Bending of Aluminum Alloy Aircraft Integral Panel
    YAN Yu1 (阎昱), WANG Hai-bo1* (王海波), WAN Min2 (万敏)
    2012, 17 (5):  635-642.  doi: 10.1007/s12204-012-1336-3
    Abstract ( 1699 )  
    Because of the light weight, high stiffness and high structural efficiency, aluminium alloy integral panels are widely used on modern aircrafts. Press bend forming has many advantages, and it becomes a significant technique in aircraft manufacturing field. In order to design the press bend forming path for aircraft integral panels, we propose a novel optimization method which integrates the finite element method (FEM) equivalent model based on our previous study, the artificial neural network response surface, and the genetic algorithm. First, a multi-step press bend forming FEM equivalent model is established, with which the FEM experiments designed with Taguchi method are performed. Then, the backpropagation (BP) neural network response surface is developed with the sample data from the FEM experiments. Further more, genetic algorithm (GA) is applied with the neural network response surface as the objective function. Finally, experimental and simulation verifications are carried out on a single stiffener specimen. The forming error of the panel formed with the optimal path is only 5.37% and the calculating efficiency has been improved by 90.64%. Therefore, this novel optimization method is quite efficient and indispensable for the press bend forming path designing.
    References | Related Articles | Metrics