When fatigue quality enhancers do not enhance fatigue quality

The role of fatigue quality enhancers is to delay or if possible eliminate crack nucleation. The most well known fatigue quality enhancers are cold working, shot peening and controlled interference fit fastening. This paper discusses the theory behind these common fatigue quality enhancers. But more importantly, this paper points count conditions where the fatigue quality enhancers did not delay crack nucleation and in some cases, sped up crack nucleation. The aim of this paper is to emphasize the need to support the analytical benefits of fatigue quality enhancers with test data.