接触压力对微动疲劳强度的影响

The Effect of Contact Pressure on Fretting Fatigue Strength

研究了接触压力对微动疲劳强度的影响,结果表明,微动疲劳极限随接触压力的增加而下降,当下降到一定程度时即保持不变.这是由于起初随着接触压力增大,磨损损伤加剧,导致微动疲劳强度下降.当接触压力增加到一定程度后.由于滑移幅度的减小使得表面损伤减轻,而此时,微动疲劳极限处的最大交变应力很低,裂纹扩展的应力强度因子低于疲劳裂纹扩展的门槛值.因而.微动疲劳极限随着接触压力的增大变化不大.

In this paper,the effect of contact pressure on the fretting fatigue strength is investigated.The results show that the fretting fatigue limits reduce with the increase of contact pressure.When the fretting fatigue limits reduce to certain extent,they keep constant.The reason is that as the contact pressure first increases,the fretting damage becomes more severe,so the fretting fatigue strength decreases.When the contact pres- sure exceeds a certain value,the surface damage is mitigated due to the decrease of slip amplitude,while at this point,the maximum alternative stress is very low at the fatigue limit.So the stress intensity factor is smaller than the threshhold value.Hence,the fret- ting fatigue limits do not change much as the contact pressure increases.