轮胎尺寸对汽车结构疲劳累积损伤影响研究

基于结构耐久试验工况,通过六分力设备与底盘杆系所采集的整车道路载荷谱,应用动力学载荷分解方法获得虚拟随机载荷谱,对车身结构进行应力分析和疲劳累积损伤计算。在底盘关键位置布置传感器,同时在车身结构中CAE疲劳分析所对应的5个高应力区粘贴应变片,先后采用3套不同尺寸参数(包括胎高和胎面宽度)的轮胎以相同的耐久工况(同一个试验场,试验路面及对应的速度相同)来进行实车载荷对比测试。针对车身结构载荷幅值、频域进行分析,并基于雨流循环计数对车身和底盘件进行疲劳累积损伤计算与分析。整车实际测试的结果表明,CAE所预测到的损伤(裂纹)位置及其里程数与路试结果相吻合;在同样使用条件下,轮胎内径越大,车身结构和汽车底盘的寿命越低,已经可进行量化对比。

Influence of Tire Size on Fatigue Accumulation Damage of Vehicle Structures

In this paper,the vehicle road load spectrum data was measured by using the 6-component wheel force transducer and the chassis bar system in the durability proving ground test. Then the virtual random spectra were obtained based on vehicle dynamics and the virtual iteration method. The stress distribution was simulated for the car body structure,and the fatigue damage accumulation was calculated. Then the force sensors were mounted to the chassis and the strain gauges were added at 5 high stress points obtained by CAE. In addition,three sets of tires with different sizes were mounted onto the same test vehicle respectively. The load spectra were acquired when the vehicle ran on the same durability road with the same speed. And the amplitude of the body structure load in frequency domain was analyzed. Furthermore, the cumulative fatigue damage for the body and parts of the chassis were calculated based on rain-flow cycle counting. Finally the results show that the vehicle damage (cracks) location and the corresponding mileage in the road test were consistent with the CAE simulation results.The bigger tire size,the lower fatigue life for the body structure and chassis.