Research On Simulation Analysis Method Of Tire Inflation Pressure Loss

Appropriate inflation pressure is necessary for the tire to achieve functions.However,the inflation pressure loss would be inevitable caused by the gas diffusion.In order to ensure the running stability of the vehicle,the tire needs to have a certain inflation pressure retention performance.IPLR—inflation pressure loss rate,is used to evaluate the tire inflation pressure retention performance.At present,an IPLR test usually lasts for several months,which greatly reduces the efficiency of relevant research.Therefore,there is meaningful to develop a quickly and economically simulation method to evaluate the tire IPLR.In order to simulate the transient tire inflation pressure loss process,the Ideal Material method is developed based on Fick's law and ideal gas law.The method was verified by rubber permeability test.In order to predict the IPLR accurately,the diffusivity and solubility of nitrogen and oxygen in more than 20 kinds of rubber are tested.In order to evaluate the gas anisotropic diffusivity in the cord-rubber composite in detail,a method for determining the gas orthotropic diffusivity in the cord-rubber composite is developed based on gas permeation test in cord-rubber composite.Passenger Car Radial(PCR 205/55R16)tire and Truck Bus Radial(TBR 12R22.5)are taken as the research object,and build their inflation pressure loss finite element models.These models include the rubber permeability data from test,the anisotropic gas diffusivity in the cord-rubber composite,and can describe the transient tire inflation pressure loss process.The IPLR tests are performed on the selected PCR and TBR,the difference between the experimental outcome and the IPLR test results is within 15%.Based on the finite element model,research the gas diffusion path.There are three main positions are found for air escape from tire: the grooves of tread,sidewall and rim end.The tire immersion tests results are basically consistent with the main air escaped positions found in the simulation.The influence of various structural parameters on IPLR has been explored by modifying the model.According to the simulation results,increasing the innerliner gauge,decreasing the liner ending length can decrease the IPLR significantly.Compare to increasing innerliner gauge,shorten linerending length provides a more cost-efficient solution to reduce IPLR.