胎圈结构参数对机械弹性车轮接地压力分布的影响

Influences of bead structure parameters on contact pressure distribution of mechanical elastic wheel

为了进一步掌握机械弹性车轮的接地特性,该文着重研究了胎圈结构参数对车轮接地压力分布的影响。建立了车轮胎圈曲梁模型,通过对车轮承载变形的理论分析,确定影响车轮接地特性的结构参数为胎圈断面高宽比、弹性环断面高宽比和弹性环分布位置。针对不同的胎圈结构参数,建立对应的车轮有限元模型并验证了模型有效性。利用有限元分析软件ABAQUS对其作静态接地特性仿真试验,结果表明减小胎圈断面高宽比、弹性环断面高宽比或弹性环分布系数,可不同程度地增大车轮接地长度和接地面积,并使车轮平均接地压力和接地压力偏度值减小。对比不同胎圈结构参数的车轮,其接地长度最大增加7.2%,接地面积最大增加21.6%。该文为优化机械弹性车轮的接地特性提供了参考。

Non-pneumatic safety tires have been introduced with a new type of elastomer, which functions as the air of the pneumatic tire. It appears to have advantages over the pneumatic tire in terms of flat proof and maintenance free. As the pursuing of consumer on car safety, handling stability and comfort continue to enhance, the study of the non-pneumatic tire is also growing. The mechanical elastic wheel is a kind of non-pneumatic tire. A mechanical elastic wheel with a non-pneumatic elastic outer ring which functions as the air of the pneumatic tire was presented to reduce the risk of puncturing, and its loading mode and contact behaviors were different from the pneumatic tire. In this paper, the influences of bead structure parameters on contact pressure distribution of mechanical elastic wheel were investigated to provide certain guidance for optimizing the mechanical contact characteristics of the mechanical elastic wheel. First of all, the Timoshenko circle curved beam model of the bead was established to describe the deformation characteristics of wheel bearing. Through the theoretical analysis of wheel bearing deformation, the main structural parameters affecting the mechanical elastic wheel contact behaviors were found, which contained bead section ratio, elastic ring section ratio and elastic ring distribution coefficient. Secondly, different bead structure parameters were put forward, and the three-dimensional finite element（FE） models of the corresponding mechanical elastic wheel were developed. The model of mechanical elastic wheel consisted of a thin flexible annular outer ring and hinge units that connected the outer ring with a rigid hub. To establish the FE model, various nonlinear factors, such as the geometrical nonlinearity, the material nonlinearity and the contact nonlinearity, were considered comprehensively. In order to prove the validity of the FE model, the load characteristic test of the mechanical elastic was conducted by tire test-bed. Finally, the commercial FE software ABAQUS was used to conduct static load simulation test for the mechanical elastic wheel, the test results were analyzed and the influence of bead structure parameters on the wheel contact behaviors was revealed. In addition, to scientifically evaluate the contact behaviors of the mechanical elastic wheel, evaluation indices of contact behaviors were introduced. The major findings are obtained as follows： 1） there is a positive correlation between bead section ratio and vertical stiffness of the mechanical elastic wheel, so is elastic ring section ratio; there is a negative correlation between elastic ring distribution coefficient and vertical stiffness. 2） the contact pressure distributions of the wheel with different bead structural parameters are similar, the shape of contact mark is approximately rectangle, the pressure of the center contact region is the largest and the pressure reduces gradually from center to edge, and the minimum appears on the regional edge. 3） reducing bead section ratio, elastic ring section ratio or elastic ring distribution coefficient, the wheel contact length and the contact area increase, and the average value and the skewness of contact pressure decrease, which would improve the performance of contact behaviors of the mechanical elastic wheel at different degrees, thereby improve the wheel gripping, driving and braking performance, the average abrasion performance, and so on. Through the study, we found that on the basis of meeting the requirement of vertical stiffness, the bead structure parameters could be appropriately adjusted when optimizing the structure of mechanical elastic wheel, so as to improve the wheel contact performance.