基于Wohler曲线的车轮弯曲疲劳试验机关联性研究

Research on Correlation of Wheel Bending Fatigue Testing Machine Based on Wohler Curve

摘要: 因为两台不同生产厂家的汽车车轮弯曲试验机的控制系统和设备结构不同，即使设备的力传感器和转速传感器都校正一致，那么输出到车轮的弯矩值也会产生差异，从而对试验结果造成影响，这是车轮行业普遍存在的现象。那么为了验证两台不同生产厂家的汽车车轮弯曲试验机之间的差异到底有多大，并且找到设备之间的关联性尤为重要。首先在两台设备上分别测试10件车轮，通过设置相同的停机条件，得到两台设备停机时车轮的循环次数和裂纹位置，从而得出两台设备车轮循环次数的差异大小。然后使用同一批次的新车轮在裂纹容易产生的位置贴应变片，用同一个应变轮分别在两台设备上采集应变数据，从而得到两台设备之间的应变差异大小。最后引入伪损伤理论，基于雨流循环计数的概念，使用nCode软件计算出两台动态弯曲疲劳试验机的累积损伤结果，得到两台设备贴片位置的累积损伤差异大小，两台设备之间累积损伤的差异验证了车轮循环次数差异大小的准确性，并通过Wohler曲线公式推导出两台设备之间的关联转化关系。

Abstract: Because the control systems and equipment structures of two automobile wheel bending testing machines from different manufacturers are different, even if the force sensors and speed sensors of the equipment are calibrated consistently, the bending moment values output to the wheels will be different, thus affecting the test results, which is a common phenomenon in the wheel industry. So in order to verify the difference between two automobile wheel bending testing machines from dif-ferent manufacturers, it is particularly important to find the correlation between the equipment. Firstly, 10 wheels were tested on two equipments, and the cycle times and crack positions of the wheels when the two equipments stopped were obtained by setting the same shutdown conditions, thus the difference of the cycle times between the two equipments was obtained. Then, strain gauges are attached to the crack-prone positions with new wheels of the same batch, and strain data are collected on two devices with the same strain wheel, so as to obtain the strain difference be-tween the two devices. At last, based on the concept of rain flow cycle counting, the cumulative damage results of two dynamic bending fatigue testing machines were calculated by using nCode software, and the cumulative damage difference between the two devices was obtained. The cumu-lative damage difference between the two devices verified the accuracy of the difference in wheel cycle times, and the relationship between the two devices was deduced by Wohler curve formula.