Failure analysis of PSV springs of 17-4PH stainless steel

This paper presents the failure analysis of the blade of a helicopter engine. From the visual examination of the fractured surface, it was possible to observe beach marks, typical of fatigue failure. The crack was initiated from the corrosion pit located on the attack edge of the blade. A non-linear finite element method was utilized to determine the stress state of the blade under rotation (operational conditions). In this analysis an undamaged blade was considered. Computations for the blade, working in the vibration conditions additionally were performed for analysis of phenomena occurring during the blade resonance. In this analysis first three mode of vibration were considered. Attention of this study is devoted to the mechanisms of damage of the compressor blade which works in the condition favorable for the pitting corrosion.