不同装夹方式下的连杆疲劳寿命

Connecting Rod Fatigue Life under Different Clamping Modes

目的分析大头间隙配合及大头小头均间隙配合这2种不同装夹方式,对连杆疲劳寿命的检测产生的不同的结果。方法采用MTS880±500 kN和MTS322±250 kN疲劳试验系统,采用不同的装夹方式模拟发动机工作状态,并通过"可靠性试验SAFL方法"进行数据处理。结果采用大头间隙配合装夹的连杆失效概率为5.2×10-5,大头小头均间隙配合装夹的连杆失效概率为0.87×10-5;并且2种装夹方式会影响连杆疲劳试验后的断裂位置。结论连杆疲劳试验中,采用大头小头均间隙配合装夹方式得到的连杆失效概率,较大头间隙配合装夹方式更小。进行疲劳试验需谨慎选择装夹方式。

Objective To analyze the different results of connecting rod fatigue life detection under two different clam-ping modes, the big head clearance fit and the big head small head clearance fit. Methods The engine working conditions under different modes of the clamping were simulated using the MTS880±250 kN and MTS322±250 kN fatigue test sys-tems. And the data was processed with the SAFL data analysis method. Results The connecting rod failure probability un-der the big head clearance fit clamping mode was 5. 2×10^-5 ,while the connecting rod failure probability under the big head small head clearance fit clamping mode was 0. 87×10^-5 . These two kinds of clamping manners affected the fracture location of the connecting rod after fatigue test. Conclusion In the connecting rod fatigue test, the connecting rod failure probability obtained by using the big head small head clearance fit clamping was lower than that by using the big head clearance fit clamping. So we must be careful when choosing the clamping manner in the fatigue tests.