Key Engineering Materials Vol. 561

Abstract: In this article, thermal conductivity of EPDM networks has been discussed using molecular dynamics simulations. The simulations are performed on four systems using adaptive intermolecular reactive empirical bond order (AIREBO) potential. The effect of Lennard-Jones (L-J) potential and torsion potential on thermal conductivity is discussed. The contribution of L-J potential to thermal conductivity is negative. However, contribution of torsion potential is positive. The results suggest that the randomly entanglement of molecular chains in EPDM networks is responsible for its low thermal conductivity.

Abstract: In this article, in order to improve the thermal conductivities and mechanical properties of EPDM filled with carbon nanotubes, phenol formaldehyde resin is used to coat to the surface of carbon nanotubes so as to improve the dispersion in rubber matrix and the combination with EPDM. The results show that with the ratio of CNTs and PF increased, the thermal conductivities of carbon nanotubes/EPDM composites show upward trend. Besides, with the increase of filler content, thermal conductivities of composites are improved as well. However, the mechanical properties of composites are declined. Therefore, more effective methods of modification of carbon nanotubes should be attempted, and more experiments should be conducted to improve mechanical properties of filled EPDM and ensure the high thermal conductivities at the same time.

Abstract: The three-dimensional flow fields produced by the modular dual-rotor of rubber continuous plasticator were numerically simulated and analyzed by using ADINA, the FEM simulation software. So the velocity field distribution of each rotor element was shown by the simulations. Through the analysis, the double rotors rotated inward had high efficiency of pumping and plasticization. The rubber compound was subjected to the strong shearing action; squeezing action and stretch effect in the rubber plasticate process. The simulation calculation had great significance for the rotor optimizing design.

Abstract: The energy saving method in tire factory has got more and more attention. In view of the characteristics that the using air capacity is vast and not steady-going in tire factory, the paper analyses and discusses the enactment of the running parameters and the choice of the running mode about the air compressing system, and sets forth the resolving project to raise the running efficiency and achieve the purpose of energy saving.

Abstract: This article is based on cooling water temperature, mixing time and rotor speed of downstream mixer to study effects of different process parameters on rubber mixing in tandem internal mixer. The experimental results show that the cooling water temperature has an important significance to improve the mixing quality, and the best cooling water temperature is about 30°C. Mixing time must be strictly controlled and the best range of mixing time is about 80 ~ 90s. Rotor speed has an significant effect on the physical properties of rubber, and the best rotor speed is about 30r/min. There is an optimal fill factor, and the best fill factor is 0.35.

Abstract: This paper uses the ANSYS software to do the finite element analysis of deflection of short fiber rubber sheeting mill roll. According to the analysis of the mill roll under different horizontal pressure, obtain analysis data of deflection of different mill roll diameters. Then according the technological parameters required to select the most appropriate mill roll diameter.

Abstract: Coated crosstie products and counter mold components are created in 3-D model using Inventor software, preparing for CAE analysis. By using Moldflow software , to determine products gate location, filling, packing, cooling, push-out processing, as well as the injection process conditions optimization of simulation analysis to find possible defects, modify and optimize the design, determine the best processing parameters and conditions. Binding using Ansys11.0 software to analyze rail sleeper mold cavity deformation, structure stress, get distribution of property of von Mises stress and displacement vector sum, in the mold cavity on the contact surface. By changing the cavity wall thickness, and other factors to improve the force which it is subjected, providing references to structure optimization of injection mold design. It has been proven that in collaborative application of these three softwares, the design of the injection mold is a very efficient and easy.

Abstract: A finite element model of the frame was established based on studying structure parameters of the YLJ series tire uniformity testing machine (TUTM). For the purpose of dynamic analysis of the frame of the YLJ series TUTM, make use of model analysis function of ANSYS to work out the first six-mode natural frequencies and vibration modes. Analysis results show that the first three-mode frequencies of the frame are 20.7 Hz, 21.9 Hz and 30.8Hz, which are far greater than working frequency of the spindle, 1 Hz. As is known, the natural frequency of the frame should be forty times more than the rotation of tire when the force variation of the tire is decomposed into tenth harmonic. In this situation, the low mode natural frequencies of the frame cannot meet this requirement, which have great influence on the test accuracy of the TUTM. The research results in this paper will provide helpful theoretical support to improve test accuracy of the YLJ series TUTM．

Abstract: Removal of dissolved oxygen from feed water is a necessary process in power industry. The hollow fiber membrane contactor is more efficient and pollution-free compared with some traditional methods. In this paper, hollow fiber is modeled by random distribution, and Gaussian function N(R, sigma) was used to model the polydisperse out radii of hollow fiber. This paper discussed the influence of different sigma on mass transfer coefficient with fiber packing density ranging from 0.1 to 0.4. It was found that, the effect of different sigma on the logarithmic mean Sherwood number decreased with increasing fiber packing density. When the packing density increased to 0.4, the removal of dissolved oxygen could meet the requirement of power industry, no matter how much value the sigma was. With the sigma increasing, the deviation of max and min Sherwood number from the average value increased gradually, except when the sigma was 0.05. This paper deduces there is a best value of sigma for membrane contactor when the fiber distribution is randomly distributed.

Abstract: Mixing performance is an important consideration in polymer extrusion processing. Besides a variety of mixing elements used in the extrusion industry, barrel also plays an important role to improve the mixing performance of the extrusion. The influence of helical grooved structure in inner wall of traditional single-extruder barrel on mixing process was investigated by using numerical simulation. POLYFLOW was used to calculate the 3D isothermal flow fields and mixing process of PVC-R in a single screw extruder with and without helical grooved barrel. Mixing performance of PVC-R in these two different structures was studied comparably. It was found that it could improve the mixing performance by helical grooved structure in the barrel, but a suitable groove depth of the helically grooved barrel should be calculated in order to avoid the extrusion throughput.