连续低速刹车对航空C/C复合材料摩擦性能的影响

Effect of braking in low-speed continuously on frictional properties of aircraft carbon-carbon composites

在HJDS-Ⅱ型动力模拟试验机上对某型号航空炭刹车副进行连续低速刹车试验,研究摩擦因数与连续刹车次数和刹车副体容温度三者之间的关系,并对摩擦性能进行分析。结果表明：在连续低速刹车条件下,炭刹车副的体容温度随刹车次数增加而缓慢均匀升高。根据航空C/C复合材料摩擦因数随体容温度的变化规律,可将摩擦过程分为4个区域：环境温度摩擦区（温度低于80℃,摩擦因数稳定并小于0.15）、突变摩擦区（温度为80~120℃,摩擦因数突增到0.3）、水解吸的粉尘摩擦区（温度为120~650℃,摩擦因数达到低温峰值0.33后小幅回落,然后缓慢上升）和氧解吸的粉尘摩擦区（温度高于650℃,摩擦因数超过低温峰值）。过多地使用连续低速刹车易导致炭刹车副温度过高和轮胎拖胎,严重威胁飞机安全。

Aircraft carbon brake was tested under the condition of continuously low-speed braking on HJDS-ⅡInertia test bench,the relationship between friction coefficient and continuous braking numbers and body temperature of C/C composites was studied,and its friction behavior was also analyzed.The results show that the body temperature of carbon brake rises slowly and evenly with the increase of braking numbers,the friction process can be divided into four regions relative to body temperature according to the variation of its friction coefficient.Those are the ambient temperature friction zone（whose temperature is lower than 80 ℃,friction factor is stable and less than 0.15）;the mutation friction zone（temperature is located between 80 120 ℃,The friction factor increases suddenly from 0.15 to 0.3）;the dust friction zone of water desorption（temperature is located between 120 650 ℃,the friction coefficient reaches low temperature peak of 0.33 at first,then declines slightly and rises slowly again）;and the dust friction zone of oxygen desorption（temperature is higher than 650 ℃,friction coefficient exceeds the low temperature peak）.Overfull continuously low-speed braking easily leads to braking discs’ body temperature being too high and tire being dragged,which will be serious threat to the safety of airplane.