Papers by Author: Ying An

Abstract: Tire simulation gradually becomes an important mean to ensure the quality of the tires. In order to guarantee the reliability of the analysis, the study on the method of obtaining the material parameters is also increasing. According to tire force situation of actual work, the acquisition method of tire rubber parameters based on simple shear test and its application in finite element analysis were studied in this paper. In this research, the international advanced dynamic mechanical analyzer was used to test the tire rubber, and the experimental results were processed by Yeoh hyper-elastic model. The hyper-elastic parameters and thus obtained could be used for finite element analysis of tires, and the simulation results showed that these parameters could be used to simulate the tire performance. In addition, the results could also provide certain guidance for the design and manufacture of tire.

Abstract: In this paper, carbon nanotubes (CNTs) dispersion behavior in epoxy resin under synergistic effect of continuous stretching flow and ultrasound oscillation was studied. A small continuous stretching machine which could provide continuous stretching flow for polymer was designed and manufactured for studying the synergistic effect of continuous stretching flow and ultrasound oscillation on dispersive property. Firstly, the influence of different initial phase angle of dual rotor and mixing time on dispersive property were studied by preparing specimens of CNTs/epoxy resin composite under continuous stretching machine. Then, the synergistic effect of continuous stretching flow and ultrasound oscillation on dispersive property was studied with various ultrasonic power and synergistic time. In this study, the morphology of blends was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that initial phase angle of dual rotor and mixing time had great effect on the dispersion of CNTs in epoxy resin. The degree of CNTs dispersion was best when the initial phase angle of dual rotor was 0°, and increasing mixing time could improve the degree of CNTs dispersion. Increasing ultrasonic power and synergistic time were helpful to disperse CNTs in epoxy resin. It demonstrated that the synergistic effect of continuous stretching flow and ultrasound oscillation had obviously effect on the dispersion of CNTs.

Abstract: In this paper, an experimental mixing equipment has been developed for producing low density material with a high volume filling rate of phenolic hollow microsphere. The experiments with the equipment aim to explore the feasibility of this equipment for industrial production and to optimize the process. Experiments have been made to evaluate the influence of the filling ratio and the mixing rotor movement on the mixing effect. The results show that when the volume filling ratio of the material to the mixing barrel is about 40% the mixing effect is the best. But with mixing time increasing, the broken ratio of hollow microsphere will increase too. To solve this problem, some changes on the rotor movement have been made. The results show that the broken ratio increasing rate becomes lower and the density becomes more uniform. These indicate that the broken ratio can be well controlled by a suitable production process.

Abstract: Absrtract. In this paper, the method of ultrasonic vibration in preparation of multi-walled carbon nanotubes(MWCNTs)/epoxy resin composites was studied. Suspension specimens of MWCNTs/epoxy resin solution prepared by different ultrasonic conditions were compared to find out the influences of operating conditions on dispersion properties. In this study, transmission electron microscopes(TEM) were used to characterize the morphology of the blends and suspension stability was used to evaluate the stability of blends. The results showed that ultrasonic power, ultrasonic time and material quantity have great effect on the dispersion of MWCNTs in epoxy resin solution. Increasing ultrasonic power and time can improve dispersion of MWCNTs, and decreasing material quantity within an appropriate range was helpful to disperse MWCNTs into epoxy resin solution. The results of suspension stability were very similar with TEM results, which demonstrate that suspension stability of MWCNTs/epoxy resin blending could be used as an assistant method to characterize the dispersion of MWCNTs in epoxy resin.

Abstract: In this paper, the 3D flow field and dynamic mixing processing in the continuous mixer with new-type rotors have been studied using finite element software package Polyflow. The influences of continuous mixer process conditions on mixing properties were analyzed by numerical simulation. The results show that the dispersion property is mainly affected by the rotational speed of rotors and the viscosity of polymer. Better dispersion property can be gained as and the viscosity increase. However, the distribution property is mainly affected by feed rate, and the distribution efficiency will reduce if feed rate is too fast.

Abstract: In this paper, employing the mixing theory of polymer and the numerical simulation of polymer processing, numerical simulation model for dispersive mixing of solid powders in polymer matrix is studied, and a multi factor accumulative size distribution function is established. Based on this, the dispersive mixing processes of black carbon/natural rubber are studied using three-dimension dynamic numerical simulation, and the influences of operating conditions on the dispersive mixing of black carbon are analyzed. The simulation results show that the final size of solid powder aggregates is depended on the rotational speed of rotors. When the maximum shear stress of polymer flow field is sufficient to overcome the cohesive force of solid powder aggregates, the size of aggregates distribution will be related with mixing time.

Abstract: As one directly method to produce nanofibers, electrospinning has been studied extensively. However, the buckling phenomenon is not understood completely especially to the process of melt electrospinning. The authors carried out a series of experimental study on this phenomenon with high speed video. This is the first article of the research, in which we defined three stages to the whole spinning process according to the time. The specialties of each stage were list out. The falling process was divided into straight-line movement, spiral swinging, and deposits on the collector three sections. The buckling reasons were provided.

Abstract: In this paper, the three-dimensional flow field and dynamic mixing processing in the continuous mixer have been studied using the professional polymer processing finite element analysis software package Polyflow. A quantitative evaluation system which consisted of dispersion mixing and distributive mixing was used to evaluate the mixing properties in simulation. Based on these numerical simulations, the influences of rotors’ phase angle and cross-section on mixing properties were analyzed. The results show that the main contribution of phase angles focus on distributive mixing and the main contribution of rotors’ cross-sections focus on dispersion mixing.

Abstract: The current work is a continuation of Part I. In this part, the simulation results showed that the free tire contour changed measurably after charging and installing it on a steel rim. A distinct stress concentration appeared on the tire shoulder part whenever the tire was charged, touching ground or rolling. When the rotational velocity of the free tire changed, the displacement of the tire crest remains stable while the tire shoulder changes considerably.

Abstract: In order to improve the dispersion homogeneity and stabilization of multi-walled carbon nanotubes (MWNT) in epoxy resin, the effect of different surfactants such as hexadecyl trimethyl ammonium bromide (HTAB), sodium dodecyl sulfate (SDS), oleic acid, Triton X-100 and BYK-9077 on the dispersion of MWNT were investigated. Suspensions of MWNTs/epoxy resin with various surfactants were prepared by ultrasonic agitation. Dispersion homogeneity of MWNT in epoxy resin was evaluated by transmission electron microscopy (TEM), and dispersion stabilization was evaluated by stationary observation. The results show that dispersion properties were not improved by HTAB, while they were improved incoordinately by SDS, oleic acid, Triton X-100 and BYK-9077. Suspensions of MWNTs/epoxy resin with HTAB, SDS, oleic acid and Triton X-100 were all delaminated quickly, it means, dispersion stabilization were not improved by these surfactants. BYK-9077 was the only surfactant which enhanced the dispersion homogeneity and stabilization of MWNTs/epoxy resin significantly. Based on this research, various weight ratios of surfactant BYK-9077 to MWNT were studied. The experimental results show that the dispersion system could reach a balance state when the ratio of surfactant BYK-9077 to MWN was 2.