Advanced Materials Research Vols. 129-131

Abstract: The numerical simulation of hot-stamping process was carried out for UHSS square-cup parts, and the influence of dies temperature on the hot-stamping process was anlysised. Besides, through the microstructure analysis and mechanical properties testing of the formed parts, effects of dies temperature on microstructures and mechanical properties of hot-stamping square-cup parts were obtained. The experiment and simulation results showed that the mechanical properties of the UHSS are strongly dependent on the temperature, so the dies temperature is one of the most important parameters that have to be taken into account in designing the hot-forming dies and the hot-forming process.

Abstract: One of the most recent techniques used by manufacturing companies to improve the product development process is computer simulation. Numerical simulation is an effective method for predicting formability of metals, and the use of computer simulation enables a significant increase in the number of tool designs that can be tested before hard tools are manufactured. Based on dynamic explicit finite element software, finite element simulation of sheet metal forming was performed to investigate the applicability of applying hydrostatic pressure on blank in multi point discrete dies. Simulation results show that using the hydrostatic pressure on blank is apposite for the process of multi point discrete dies.

Abstract: Expander is undertaking the important task to offer essential cold to the air separation course, that the cold produced to make air liquefy, compensate cold loss of the whole separation process. In order to guarantee the operation of the expander system safe and reliable, through analyzing to this system, adopting DCS system to configuration control, make the control of expander system simpler and more convenient, more ocular, and effective, it has certain reference function to other equipment’s control of the air separation.

Abstract: Bamboo forest was a dominantly ecological and sustainable economic recources. However, bamboo extractives and hemicellulose were nearly complete dissolved out in preparation of the fiber, this would result in more serious water pollution and meanwhile bring a great waste of biological resources. Thereby, In order to obtain the way to lower the negative impact of the extractives and hemicellulose, the Phyllostachys pubescens biomass was treated in alkaline solutions at room temperature and the extractives obtained was analyzed by SIZER basen on the full-factor method. The results were following as: (1) Sort of alkaline and concentration of alkaline had a significant influence on the leaching rate of particles at 0.01 level. And the optimal concentrations of KOH, NaOH, LiOH were 16.0%, 17.5% and 17.5% at 25°С, respectively. (2) Pretreatment, extraction time and sort of alkaline had no influence on the leaching rate of particles. But the benzene/ethanol pretreatment was valuable and necessary. when 16% NaOH and 17.5% KOH were used, the optimal extraction time were all 16h to untested and tested samples.

Abstract: Adhesive bonding is a high-speed fastening technique which is suitable for joining advanced lightweight sheet materials that are dissimilar, coated and hard to weld. Major advances have been made in recent years in adhesive bonding technique. Latest literature relating to finite element analysis (FEA) of adhesively bonded single-lap joints (SLJs) is reviewed in this paper. The recent development in FEA of SLJs is described with particular reference to three major factors that influence the success of adhesive bonding technique: failure mechanism, environmental effects and mechanical behavior. The main FE methods used in FEA of SLJs are discussed and illustrated with brief case studies from the literature. Areas where further useful progress can be made are also identified.

Abstract: In order to obtain the parameters of viscoelastic damping material model, namely GHM, which account for frequency dependence and allow time-domain analysis of viscoelastic composite structure, a new optimization algorithm which is composed of particle swarm optimization(PSO) and sequential quadratic programming (SQP) algorithm is presented . The results are compared with those of standard rheological model and fractional derivative model as well as the experiment results. The results show that the hybrid algorithm can obtain the better optimum solution for the model and have a fast convergence , it will correctly describe the constitutive characteristics of viscoelastic damping material.

Abstract: Electrorheological (ER) fluids are new materials with good properties such as dielectric constant, dielectric loss or conductivity, which display remarkable rheological behavior, being able to convert rapidly and repeatedly from a liquid to solid when an electric field is applied or removed. In this study, suspensions of alumina (A) were prepared in silicone oil (SO). The effects of electric field strength and temperature of the suspensions on thermal conductivity were determined. Thermal conductivity measurement in different conditions was carried out via experimental instrument with high-voltage power supply and water heating device to investigate the effects of electric field strength and temperature on ER performance and thermal conductivity. The results show that the thermal conductivity is in accordance with ER properties enhanced by increasing the field strength and decreasing the temperature.

Abstract: By turning testing workpieces of different hydrogen content Ti6Al4V alloy, measuring cutting force and surface roughness as well as observing chip morphology, the effect of hydrogen content on machinability of Ti6Al4V alloy has been studied. Results of this experiment indicate that machinability of Ti6Al4V alloy improves with increasing hydrogen content at a certain range of hydrogen content, and there is a turning point of peak value, in excess of the hydrogen value, with the hydrogen content increasing, machinability of Ti6Al4V alloy is reduced.

Abstract: The purpose of this paper was to evaluate the capacity of anion ion exchange fiber to uptake the heavy metal(Co2+、Cu2+、Zn2+、Cd2+、Pb2+、Ag+) from the water. A new polyamine-type ion exchange fiber(IEF) based on polyacrylonitrile (PAN) with higher exchange capacities was prepared by crosslinking through hydrazine hydrate, followed reacting with diethylene triamine. FT-IR analysis indicated that amine, imido, acylamino and carboxyl groups were introduced into PAN fiber through the surface modified reaction of cross linking and amination. The structures of the IEF were characterized by means of SEM. The results showed that the surface of fiber became rougher and thicker and more heterogeneous. The static and dynamic adsorption experiments demonstrated the high selective adsorption property of the IEF for Ag+ and Cu2+. Furthermore, the adsorption mechanism for the metal ions with IEF was investigated with the FT-IR spectra studies.

Abstract: This article discussed the preserve effect of the WC-HVOF coating to hydraulic turbine based on the research of sand abrasion in hydropower stations on the upstream of Yellow River. At the same time the importance role of WC coat for Hydraulic turbine protection and the great economic benefits from reasonable utilization of WC-HVOF coating are also been discussed in this article, using Sanmenxia hydropower stations as an example. All these have important reference significance for the other similar stations to use WC-HVOF coating to protect the hydraulic turbines.