Sensors and Materials: Advanced Researches

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Authors: Lei Chen, Hui Qin Chen, Zhi Hua Li, Qiao Yi Wang
Abstract: Simulation method has become an increasing important problem to establish the trustworthiness of models in the finite element simulations. Finite element models in sheet metal forming, which involves large deformations, large displacement and friction, are uncertainly with different methods. Finite element models based on different Lagrangian methods have been used to analyze the deep drawing process. The tools are modeled as rigid surfaces. The blank is modeled as a deformable body. The interaction of sliding surfaces is modeled with a modified Coulomb friction law. The Finite element results of strain and thickness distributions are validated by comparison with the experiment. It is shown that the main difference of Total Lagrangian formulation (T.L.) and Updated Lagrangian formulation (U.L.) lies in the large displacement and deformation, whilst agree well with small displacement and deformation.
Authors: Zakaria Boumerzoug, Nedjma Chérifi, Thierry Baudin
Abstract: In this investigation, grain orientation has been studied in an industrial aluminium Al99.5 which has been welded by TIG process. The optical microscopy and EBSD (Electron Back Scattered Diffraction) were the main techniques used to illustrate the effect of welding on grain orientation in fusion zone and in heat affected zone. Epitaxial growth has been observed in weld joint and texture of each zone has been determined. On the other hand, the effect of isothermal heat treatment at 400 °C on homogenization of welded joint has been also studied. It was shown that the cube orientation {001}<100> is the dominant texture component in welded joint before or after heat treatments.
Authors: Ching Hui Tai, Chun Ho Yin
Abstract: This paper discusses the process of calculating the lay-up configuration and structural stiffness of carbon fiber composite bike frame. First, a program is written in ANSYS macro language to calculate the lay-up configuration of the composite. The user only has to input the geometry, fiber orientation and sequence of individual layer, according to the original shop drawing. The program will then calculate the lay-up configuration of all the details for the whole structure automatically, and create the finite element model for ANSYS. The stiffness is then analyzed according to the product specification, and also compared with test result to evaluate the validation of the model. This automated process can accelerate the development time frame, and also work as the basis of parametric model for future design optimization.
Authors: Jiang Wen Liu, Yong Zhong Wu
Abstract: An investigation has been made into the machining feasibility when wire electro-discharge machining with an extremely high travelling speed of wire electrode (WEDM-HS) has been employed to process particle-reinforced 6061 Al matrix composites with 20-vol% Al2O3 (20ALO). And in this study, for the water based emulsion is used as working liquid, there exists an electrochemical effect. And thus, the EDM spark can operate under a relatively large spark gap size condition, and this would be helpful for the removal of the loosen particles and the machined debris. In this study, the material removal rate (MRR) has been examined. Since there are many factors that can influence the MRR during the wire electro-discharge machining process, in order to determine which factor has the most significant effect on the MRR and to obtain the optimal machining parameters, the relative importance of the various machining parameters on material removal rate was analysed by employing an orthogonal design. The results of the orthogonal analysis show that to obtain a high MRR for WEDM-HS machining of 20ALO materials, the duty cycle has the most significant effect on the MRR among current, pulse duration and duty cycle. And the impact of significance for the different factors follows the sequence of duty cycle > current > pulse duration. And under the experiment condition of this study, a duty cycle of 1:4, a current of 5A and a pulse duration of 32μs is the best arrangement for the MRR.
Authors: Xu Long An, Qi Bin Liu, Bo Zheng
Abstract: To obtain the coating with excellent properties, FeWCrMnCoCuTix (x=0.2, 0.4, 0.6) high entropy alloys coating on 45 steel were prepared by laser cladding. By means of OM, XRD and microhardness tester, the effect of Ti content on microstructure and properties of coating is investigated. The experimental result shows that the phase composition of HEAs coating is simple body-centered cubic and face-centered cubic. The microstructure of these alloys is mainly dendrite crystal with grains were fine and uniform. When Ti content increases to x=0.4, the hardness of the coating reaches a maximum (639HV0.2). Key words: HEAs; FeWCrMnCoCuTix; coating; laser cladding; microstructure and properties
Authors: S.F. Wang, Q.P. Ding, X.T. Zu
Abstract: LaFeO3/Fe2O3 and Mn2O3/Fe2O3 magnetic nanocomposites have been prepared by a modified polyacrylamide gel route. The XRD result indicates the formation of LaFeO3/Fe2O3 and Mn2O3/Fe2O3 nanocomposites. Scanning electron microscope (SEM) observation shows that the LaFeO3/Fe2O3 particles appear to be regularly spherical in shape and highly uniform in size with a diameter of ~ 80 nm, while the Mn2O3/Fe2O3 sample exhibits a relatively broad particle size distribution with an average particle size centered around 20-60 nm. Result of vibrating sample magnetometer (VSM) of LaFeO3/Fe2O3 magnetic nanocomposites revealed that coercivity values decreased with the increase sintering temperature. However, the coercivity values of Mn2O3/Fe2O3 magnetic nanocomposites appear to an anomaly phenomenon.
Authors: Na Li, Hong Hai Shen, Shi Quan Liu
Abstract: Sintered glass-ceramics have been successfully prepared using glass particles derived from a waste water flocculate. Influence of heat treatment conditions (sintering temperature and soaking time, heating rate) and size of the glass particles on the microstructure and density, hardness of the obtained glass-ceramics has been studied. The results show that the prepared glass-ceramics have gehlenite and anorthite as main crystalline phases. SEM analysis indicates that the size and morphology of the crystallites vary with the preparation conditions. A dense glass-ceramic with a high hardness can be obtained by sintering glass powder sized smaller than 0.075mm with a relatively slow ramping rate (3°C/min) to a temperature higher than the crystallization peak temperature of the parent glass for a short period of 30min to 1h.
Authors: Zhang Lu, Dan Xia, Zhen An
Abstract: The foaming reaction so that all water-gel reaction and foaming reaction to reach equilibrium, the excellent thermal insulation material was prepared by the regulation of the catalyst, a nucleating agent and an isocyanate. By experiment we know that the amount of stannous octoate catalyst 6%, 4% of the amount of nucleating agent CaCO3, and the case of 100% of the amount of isocyanate, the density of the foam material and the mechanical properties of the insulation material to achieve the best value.
Authors: Lei Chen, Zhi Xin Yu, Wei Ping Cui, Li Juan Qin
Abstract: Development of normal stress in the direction perpendicular to the asphalt mixture is an important feature of the nonlinear viscoelastic behavior of asphalt binders. In this paper, this phenomenon was studied with the help of stress-relaxation experiments in torsion.  Results indicate that stress relaxation test by controlling strain could be used to evaluate the stress relaxation ability of asphalt mixture. With the aging degree of asphalt mixtures increased, the low temperature cracking resistance got worse; the higher the temperature is, the faster the stress relaxed; the smaller the initial strain, the worse the stress relaxation ability also. The viscoelasticity of asphalt mixture could be simulated by exponential model fractional and the experiments well supported the modeling results.

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