Crack Arresters Design for Fatigue Strength Improvement of Additively Manufactured Components

Abstract

Additive manufacturing applied to polymeric as well as metallic materials offers a lot of advantages, today not yet fully explored. They can potentially enhance the structural efficiency of the components, which means, for a given loading condition, the section uses as little material as possible. As a matter of fact, the complete freedom in parts shape design could be exploited to increase the fatigue strength of structural components by crack arresters (CAs) design. From classical fracture mechanic theories, it is well known that when the fatigue crack meets a hole, the consequent sudden reduction of the stress concentration ahead of the crack tip promotes the arrest of the crack propagation itself. Using additive manufacturing, it is now possible to design structural components with CAs in the vicinity of crack initiation points like notches. This paper is aimed at exploring, with preliminary experiments supported by numerical analyses, this possibility. It was found that crack arresters effectively enhance the fatigue life of a notched component provided that their shape and position are designed properly.