高速动车制动盘盘面裂纹扩展寿命评估方法研究

Research of brake disc surface crack propagation and life evaluation for high speed EMUs

制动盘在锻造生产过程中很难做到没有微裂纹或缺陷,同时制动盘在运用过程中各种损伤积累到一定程度也会产生裂纹,但制动盘产生了裂纹并不代表必须立即结束其服役。因此提出裂纹寿命估算的评价方法来估算制动盘的热疲劳寿命非常重要。采用线弹性断裂力学方法,计算不同裂纹长度下应力强度因子,根据Pairs曲线得到制动盘裂纹的扩展寿命,并考虑裂纹间的相互作用,对裂纹的热疲劳寿命进行修正,提出比较合理的寿命评估方法,并通过试验验证表明计算方法的有效性,为制动盘的检修周期提供参考。

It is difficult to produce micro-crack-free or defect-free brake discs in the forging process.At the same time,cracks may also occur when various damages accumulate to a certain extent during the use of brake discs.However,the occurrence of cracks in brake discs does not mean that their service must be immediately terminated.It’s therefore very important to work out an evaluation method for crack life estimation to estimate the thermal fatigue life of brake discs.By the aid of the linear elastic fracture mechanics,the stress intensity factor is calculated for different crack lengths.The crack propagation life of the brake disc is obtained based on the Pairs curve,and the interaction between cracks is considered to modify the thermal fatigue life of the cracks.A reasonable life evaluation method is therefore proposed,and the effectiveness of the calculation method is verified through experiments,providing a reference for the brake disc maintenance cycle.