子午线轮胎胎圈裂纹的有限元分析

Finite Element Analysis on Bead Crack in Radial Tire

轮胎内部的稳定对汽车行驶的安全性起着极其重要的作用,气压过高和过低都会影响车身稳定性,从而引发交通事故。米其林公司发明的子午线轮胎具有操纵稳定性好、滚动阻力小、耐磨性好、高速性能好等卓越的使用性能,使其成为众多企业和研究机构研究和优化的方向。针对子午线轮胎在充气工况下含胎圈裂纹扩展趋势及扩展角度问题,建立了子午线轮胎有限元模型,确定了模型材料、边界条件及载荷情况。运用有限元软件对子午线轮胎充气过程进行动态仿真,得出充气完成时刻的Mises应力分布图。分析结果表明:轮胎在充气完成时刻的最大应力发生在胎圈部;在轮胎胎圈部分易产生裂纹处出现不同初始倾角的等长裂纹,计算出裂纹尖端周围沿不同方向扩展时的J积分值。根据所得数据判断裂纹尖端的开裂方向,并分析出裂纹尖端正方向的J积分和裂纹尖端开裂方向随初始倾角的变化规律:裂纹尖端在一定区间内开裂,且开裂方向及J积分峰值随初始倾角周期性波动。有限元分析结果与实际轮胎胎圈裂纹损坏情况基本一致,加深了对轮胎损伤机理内在本质规律的理解,为工程人员进行轮胎结构优化以及开发新型轮胎起到一定的理论指导作用。

The stability of the inside of tire plays a very important role in the vehicle safety, both high air pressure and low air pressure affect the stability of vehicle body, thus causing traffic accidents. The radial tires of Michelin company have excellent operating stability, small rolling resistance, good wear resistance, good high-speed performance, etc., which makes it the research and optimization direction of many enterprises and research institutions. Aiming at the problem of radial tire bead crack propagation tendency and expanding angle under the condition of inflation, a finite element model of radial tire is established to determine the material, boundary condition and load of the model. The dynamic simulation of radial tire inflation process is carried out by using FE software, and the Mises stress distribution at the inflation completion time is obtained. The analysis result shows that(1) the maximum stress of tire at the completion time of inflation occurs in the bead;(2) in the tire bead part it is easy to produce different initial angled isometric cracks where cracks are prone to occur, and the J integral values when the crack extending around crack tip along different directions are calculated. According to the obtained data, the crack orientation of the crack tip is determined, and the change rules of the J integral of the forward direction of the crack tip and the crack tip orientation with the initial dip angle are analyzed. It shows that the crack tip cracks in a certain interval, the crack direction and the J integral peak fluctuate with the initial dip angle. The FE analysis result is basically the same as the actual tire bead crack damage, and it deepened the understanding of the inherent essential law of tire damage mechanism, which can be used as a theoretical guidance for the engineers to optimize the tire structure and develop new tires.