Papers by Keyword: Crack Growth Retardation

Abstract: Drilling holes in the vicinity of the crack tip turns the crack into a notch and reduces the crack tip stress intensity factor. In this paper, a new idea is used in which instead of a single hole, two symmetric and interconnected holes are drilled at the crack tip. The main concept of double stop-hole method is to reduce the stress concentration at the edge of stop-holes in the cracked structural elements. The double stop drill hole method can be used to increase the fatigue life of the cracked components. The fatigue crack growth retardation is examined using an experimental investigation coupled with a stress analysis on the efficiency of proposed double stop-holes. The distance between the hole centers is considered as the main parameter affecting the efficiency of this method. The results show that the fatigue life extension caused by the double stop-hole method is significantly more than the conventional single stop-hole method.

Abstract: The purpose of this study was making evident the overload effect in a spectre with constant amplitude cycles. The crack growth simulation was made on cracked specimen and was studied for four loading cases. Fatigue crack growth rate was calculated applying NASGRO equation and the crack growth retardation analyzed.