Papers by Author: Yu Mei Ding

Abstract: The article proposed a kind of new structure for aircraft tire, which includes double firm rings. The aircraft tire of double firm rings was simulated in the instant of landing by finite element analysis, then the simulation result was compared with the one of ordinary aircraft tire. The result indicated that the grounding area and deformation of aircraft tire with double firm rings was less than that of ordinary aircraft tire, which can decrease the rolling resistance and improve high speed performance. In addition, the larger contact pressure located the central region of the contact surface, which can reduce the damage of shoulder rubber and lengthen the life of the aircraft tire.

Abstract: In the process of rotational molding, there are two important parameters, temperatures in the rotational molding machine’s oven and in the mold. It is the crux of the evaluation about the molding efficiency and products’ quality to control the time of the temperatures to reach the top. This article puts forward to two time parameters C1, C2 to show temperatures’ change in machine’s oven and in the mold during the molding processing. Besides, these two time parameters are applied to direct the structure design of rotational molding machines and molds. Meanwhile, the theoretical analysis agrees well with the experimental data from the comparison between them. Hence, the efficacy and practicality of the two parameters are well verified.

Abstract: Three different kinds of carcass A, B and C for aircraft tires were presented in the article, which is based on the different length of rolling up for carcass cord across the bead ring. And then they were simulated by applying finite element analysis method when aircraft tire was landing in an instant. The simulation results indicated that, the carcass structure of rolling up from the side of bead extending to the other bead (A type) has the minimum deformation, which can reduce the outward of bulge for the side wall and effectively resolve the failure problem for rubber in the sidewall of tire , what’s more , it can prolong the life of aircraft tire to a certain degree and provide good braking performance.

Abstract: This article mainly introduced the structure and the principle of gas barrier of the rubber nano-laminated composite materials with alternating layer structure and excellent gas barrier property. Due to the fact that the barrier resin material was dispersed in matrix rubber evenly and parallelly in nanometer, the phase structure lead to the existence of multipath movement and deep penetration in the composite materials, thus the permeability coefficient of composite materials were reduced significantly. So the rubber nano-laminated composite materials owned excellent gas barrier performance.

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: Polymer melt flowing in the multiplying element and matched die was simulated for the flowing uniformity and pressure distribuiton based on ANSYS. The results of simulation revealed that the height difference between outlet and inlet sections of the channels in multiplying element, the length of transition region and forming region of molding die all affected pressure distribution and velocity uniformity at the outlet.

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: This work presents the effect of V cut and square cut rotors in circular tubes for turbulent heat transfer using computational fluid dynamics (CFD) modeling. The computational results are in good agreement with experimental data. The obtained results reveal that the use of square cut rotors leads to higher Nusselt number than use of V cut rotors. The results also show that the heat transfer rate, friction factor and thermal performance factor of rotors with square cut increase with the increase of width (a) and depth (b) of rotors’ cut. Square cut rotors with a=b=3 yields higher mean thermal performance factor than those with other width and depth, a=b=1, 2 and the highest thermal performance factor of square cut rotors at a=b=1, 2, 3 are found to be 2.08, 2.11 and 2.13.

Abstract: Based on the advantages of polymer materials over other materials, rotors which are made of the polymer material, are the functional elements of the rotor-assembled strand, and rotate under certain mass flow rate to obtain heat transfer enhancement and online automatic cleaning. The paper carried out numerical studies on heat transfer and friction loss characteristics of the tube fitted with rotors of different spaces. The comparison of the field synergy angle between plain tube and the tube fitted with rotors was also presented in the paper. The numerical data had good agreement with the experimental data. The numerical studies indicated that the field synergy angle of the rotors inserted tube were significantly smaller than that of the plain tube, which validated that the rotors could significantly enhance heat transfer process and had a better comprehensive performance of heat transfer enhancement though extra friction loss was generated. In addition, both the Nusselt number and friction factor of the tube fitted with rotors increased with the increasing space between rotors; the thermal performance factor of the rotors were all higher than 1, which validated the heat transfer enhancement function of the rotors; meanwhile, the thermal performance factor increased with the space between rotors.