| Tire vulcanization was an important step in the production process, directly determining the mechanical properties of the tire, which was the most energy-intensive during the production. The traditional low-profile tire vulcanization process did not take post cure into account, which probably resulted in waste of energy. Finite element simulation of the tire vulcanization could show the whole process, in particular the importance role of post cure in the tire vulcanization. If the simulation results presented that the effect of post cure could not be ignored, then there was need for improvement of traditional process and it provided process optimization space. In this paper, the simulation method was innovative. The subroutine HETVAL was used to load the reaction heat and analysis with reaction heat and analysis without reaction heat were compared. By developing ABAQUS postprocessor, the subroutine UVARM was used to directly get vulcanization degree field.In order to find ways to improve the curing process, in the paper effect of process parameters on the flat tire vulcanization had been studied. Curing parameters included heating temperature, curing time and preheating temperature. Corresponding to these three factors, the three-dimensional model was established by ABAQUS finite element software to carry out three groups of simulation. Results showed that effect of heat source temperature on the maximum temperature was the largest, preheating temperature was the lowest; effect of heat source temperature on the curing degree was the largest, the curing time was lowest. According to the data analysis the optimal process parameters had been raised.Traditional steam curing machine had capsules and steam room, heating tire with superheated steam. Steam heat transfer was inefficient and energy-intensive. Due to steam condensation, temperature of vulcanization bladder upside was lower than temperature of bladder downside, leading to uneven vulcanization. The direct pressure curing process heated tire with electromagnetism, which made tire temperature field homogeneous and precisely controllable. Heat transfer efficiency of direct pressure process was higher by the way of contact heat transfer. Based on ABAQUS software and subroutine HETVAL and UVARM, the actual vulcanization process was simulated to get temperature field and cure degree field of 255/30R22 tire.Then direct pressure electromagnetic heating curing machine was developed. Heating coils was put at the surfaces of upper plate lower plate and heating drum. The coils heat machine fast, but the plates and drum hardly heat evenly. The intensively generated heat made sidewall of tire over cured. In this study the reason of intensive heat generation in the new designed machine was researched with software ANSOFT.In this paper the temperature measuring device for 255/30R22 tire curing process was built. The green tire temperatures at sampling points were measured for both steam curing process and electromagnetic direct pressure process. On the basis of a series of experiment data the finite element simulation was carried on. Then process optimization and structural optimization work was done. The main results were as follows:(1) Thermal physical parameters of each rubber of the green tire were tested.I was responsible for the experiment sample preparation and monitoring test data.(2) Vulcanization temperature testing device for the green tire was built to obtain temperature data for both steam curing process and electromagnetic direct pressure curing process. The advantages and disadvantages of both processes were analyzed based on the measured data; verifying the rationality of the finite element model.(3) Comparison simulations of reaction heat curing and non-curing reaction heat were done to get the respective temperature field. The cure degree field considering reaction heat was obtained with UVARM routine. After analyzing clouds the following conclusions were given:curing reaction heat effect temperature curve peak, but had little effect on the final temperature of the tire. Compared with the measured values, the real curing process was better to better simulated with the reaction heat load. In addition to the tire tread other rubber was over cured. Results showed that the simulation contribution of after vulcanization to cure degree could not be ignored, which provided direction and methods for the curing process optimization.(4) Based on curing time, heat source temperature, preheating temperature, three groups of simulations had been carried out in the paper, the following conclusions could be drew from temperature curves and cure degree curves:According to the influence on the highest temperature from high to low, factors were the heat source temperature, curing time, preheating temperature. According to the influence on vulcanization degree from high to low, factors were the heat source temperature, preheating temperature, curing time. The traditional crafts had optimizable space. By only adjusting the single factor, vulcanization time could be adjusted to the 600 s, heat source temperature could be adjusted to 170 "C, preheating temperature could be adjusted to 130?.(5) In this paper, with 255/30R22 tire as example, the finite element model was established by using the software of ABAQUS, the two groups of simulation were respectively carried out. One group was heated by stream and the other was heated by electromagnetism. Reaction heat and after cure effect were considered in two sets of simulations. Subroutine HETVAL was loaded by curing reaction heat. By comparing the cure degree at different sample points heated by stream and electromagnetism, it could be obtained that cure degree of rubber heated by electromagnetism expect triangle core rubber was increased, about a third, compared with stream heating. Tire was heated rapidly to a high temperature and maintained about a stable value by electromagnetic heating. Electromagnetic heating was more efficient, more controllable and more energy-saving than stream heating.(6) Simulation analysis for the existing coil heating with software ANSOFT was carried on to discover the reason of the uneven heat distribution, and a new coil structure of the drum was designed for the existing curing machine. Simulation results showed that the existing coil structure was simple, but the heat was mainly concentrated in the drum shoulder. The optimized coil was easy to install and heated evenly, meeting the heating needs of the green tire.(7) In this study the reason of intensive heat generation in the previously used heating plate was researched and a new heating structure for upper and lower plates was given. By the software ANSOFT both of the plates were simulated. Results presented that the previously used plate indeed existed heat generation concentration, which was consistent with the actual observation; heat generation area of the previously used plate looked like a circular ring and was near to the upper surface. Although its structure was simple, the spiral coil was not fit for the electromagnetic curing process. The new designed heating plate generated inside and evenly. Electromagnetic heating method was widely used in many industrial fields. Different process had different requirements for temperature control and temperature distribution. Direct pressure electromagnetic heating process required the green tire to be heated and cured uniformly. Therefore the new designed plate whose coils were inserted in an equilateral triangle was chosen. |
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